April 27, 2016

Release Notes for Safari Technology Preview 3

WebKit Blog

Safari Technology Preview Release 3 is now available for download. If you already have Safari Technology Preview installed, you can update from the Mac App Store’s Updates tab. Release 3 of Safari Technology Preview covers WebKit revisions 199086–199865.

JavaScript

  • Added support for Symbol.isConcatSpreadable per the ES6 spec (r199397)
  • Made RegExp constructor get the Symbol.match property to decide if an object should be constructed like a RegExp object per the ES6 spec (r199106)
  • Changed String.match and String.search to use RegExp constructor per the ES6 spec (r199144)
  • Corrected how function declarations are hoisted per the ES6 spec (r199179)
  • Improved parsing of ES6 arrow functions (r199352)
  • Added RegExp.prototype[@@split] and made String.prototype.split use it per the ES6 spec (r199731)
  • Added RegExp.prototype[@@search] (r199748)
  • Updated the treatment of invoking methods on RegExp.prototype per the ES6 spec (r199545)
  • Made more test cases pass with ES6 RegExp unicode flag (r199523)
  • Added support for caching accesses to arguments.length for a performance speed-up (r199240)
  • Corrected the behavior of throw() for generators yielding to an inner generator per draft ECMAScript spec (r199652)

CSS

  • Implemented the functional :host() pseudo class (r199291)
  • Improved support for SVG cursor images (r199625)
  • Started using OpenType math fonts by default for MathML (r199773)
  • Fixed measurement of hanging punctuation (r199777)
  • Improved hyphenation when the last line in a paragraph only contains one syllable of a word (r199818)
  • Fixed a layout problem affecting CSS Grid items without a static inline position in RTL languages (r199098)
  • Fixed positioned items with gaps for CSS Grid (r199223)
  • Added support for CSS Grid grid-template-columns repeat(auto-fill, …) and repeat(auto-fit, …) (r199343)
  • Fixed positioned items with content alignment in CSS Grids (r199657)
  • Started using grid-template-areas to determine the explicit grid (r199661)
  • Corrected CSS Grid layout by using the margin box for non-auto minimum sizes (r199728)

Web APIs

  • Added support setting and retrieving Blob values in IndexedDB (r199120, r199230, r199499, r199524, r199708, r199730)
  • Corrected MessageEvent.source result once window has been fully created (r199087)
  • Improved stability when the first child of a shadow root is a comment node (r199097)
  • Made CSS be a proper constructor on the window object with static functions (r199112)
  • Exposed the Crypto constructor on the window object (r199159)
  • Added support for display: contents on <slot> elements (r199151)
  • Fixed FontFace so it will be properly reject the returned promise if Content Security Policy blocks all the URLs (r199611)
  • Made FontFaceSet handle null correctly (r199216)
  • Corrected DOMTokenList.contains() so it does not throw an exception (r199296)
  • Made Selection.deleteFromDocument not delete a character when the selection is a caret per the spec (r199585)
  • Improved the IndexedDB bindings to better match the spec (r199750, r199774)
  • Made AudioBufferSourceNode.buffer nullable (r199751)
  • Improved stability handling a wheel event that closes a frame (r199181)

Web Inspector

  • Made it possible to expand objects in the Instances heap snapshot view to see what it retains (r199379)
  • Improved performance dramatically in the Timelines tab when recording pages with a lot of rapid activity and for long recordings (r199747)
  • Improved JavaScript pretty printing performance by using Esprima and by no longer blocking the main thread (r199168, r199169)
  • Improved the profiler’s sampling rate to get closer to a 1ms sample frequency (r199092)
  • Improved filtering in Open Quickly dialog (r199143, r199226)
  • Made the Open Quickly dialog keep its resource list up to date (r199207)
  • Stopped trying to match color patterns in JavaScript source code to improve performance of large resources (r199095)
  • Changed take snapshot navigation button to a camera glyph (r199177)
  • Corrected source code location links in the JavaScript profile Call Trees view (r199201)
  • Made XHRs and Web Workers full-text searchable (r199263)
  • Improved the appearance of DOM nodes in object previews (r199322)
  • Improved the tab bar rendering when the tabs are small (r199325)
  • Corrected dock controls disappearing from the toolbar after leaving fullscreen (r199395)
  • Started remembering the zoom factor as a persistent setting across sessions (r199396)
  • Corrected sourceMappingURL not being used when sourceURL was also set (r199688)
  • Started localizing sizes and times by using Number.prototype.toLocaleString (r199635)
  • Made sourceMappingURL work more reliably across reloads (r199852)

Rendering

  • Improved the time to display for some pages — allowing a short page header to render immediately before other content populates later (r199155)
  • Fixed page tile layers disappearing when graphics acceleration is unavailable (r199130)
  • Made font-size: 0 render as 0 width when text-rendering: optimizeLegibility is used (r199150)
  • Corrected focus ring drawing at incorrect location on image map with a CSS transform (r199247)
  • Made negative letter-spacing affect the right edge of the content’s visual overflow (r199516)
  • Corrected compositing for WebGL based canvases after they changed size (r199536)
  • Started clearing the rendered icon on <input type=file> when an empty files list is set (r199540)
  • Improved performance of border-collapse: collapse on tables (r199552)
  • Improved rendering of select[multiple] to better match other browsers (r199553)
  • Fixed backdrop filter so it honors visibility: hidden (r199862)

Security

  • Made nested browsing context created for <object> or <embed> respect Content Security Policy’s object-src directive (r199527)
  • Started ignoring Content Security Policy meta tags if it is not a descendent of <head> per the spec (r199163)
  • Started ignoring report-only Content Security Policy directives delivered via meta tag per the spec (r199538)
  • Started ignoring paths in Content Security Policy URL matching after redirects per spec (r199612)
  • Removed support for X-Frame-Options in <meta> per the spec (r199696)

Networking

  • Stopped speculatively revalidating cached redirects (r199521)
  • Stopped cacheing responses with Content-Range headers to avoid serving incorrect results (r199090)
  • Fixed clearing the application cache when removing website data in Privacy preferences (r199204)

Accessibility

  • Changed the application role description to “web application” to avoid confusion with the top-level system application description (r199260)
  • Made presentation role be preferred over child <title> and <desc> elements in SVG content (r199588)

By Timothy Hatcher at April 27, 2016 05:00 PM

April 26, 2016

Updating Our Prefixing Policy

WebKit Blog

When implementing new features for the Web, it’s important for us to be able to get them into the hands of developers early, so they can give new things a try. (Of course, this also helps us identify and fix bugs!) In the past, browsers did this by using vendor-prefixed names for features. This was intended to protect the Web from the churn of spec and implementation changes. Browsers would eventually implement the standard version with no prefix and drop support for the prefixed version.

Over time this strategy has turned out not to work so well. Many websites came to depend on prefixed properties. They often used every prefixed variant of a feature, which makes CSS less maintainable and JavaScript programs trickier to write. Sites frequently used just the prefixed version of a feature, which made it hard for browsers to drop support for the prefixed variant when adding support for the unprefixed, standard version. Ultimately, browsers felt pressured by compatibility concerns to implement each other’s prefixes.

The current consensus among browser implementors is that, on the whole, prefixed properties have hurt more than they’ve helped. So, WebKit’s new policy is to implement experimental features unprefixed, behind a runtime flag. Runtime flags allow us to continue to get experimental features into developers’ hands while avoiding the various problems vendor prefixes had. Runtime flags also make it easier for us to have different default settings between stable builds and preview builds such as Safari Technology Preview.

We’ll be applying our updated policy to new feature work going forward. Whether or not a runtime flag should be on or off on WebKit trunk (and thus in nightly builds) depends on the maturity of the feature, both in terms of its spec stability and implementation maturity.

What does this mean for Web developers?

Initially, developers shouldn’t notice anything different. In the longer term we hope this change will make it easier for you to try out upcoming features. As always, we encourage you to give in-progress features a try. Feedback and bug reports on experimental features are very welcome.

What about currently prefixed features?

We’ll be evaluating existing features on a case-by-case basis. We expect to significantly reduce the number of prefixed properties supported over time but Web compatibility will require us to keep around prefixed versions of some features.

We invite comments and feedback on the new policy from Web developers, educators, and our colleagues working on other browser engines. Feel free to reach out to me on Twitter (@hober), Jon Davis (@jonathandavis), @webkit, or email me directly at hober@apple.com.

By Edward O'Connor at April 26, 2016 02:00 PM

April 16, 2016

OpenType MATH in HarfBuzz

Frédéric Wang

TL;DR:

  • Work is in progress to add OpenType MATH support in HarfBuzz and will be instrumental for many math rendering engines relying on that library, including browsers.

  • For stretchy operators, an efficient way to determine the required number of glyphs and their overlaps has been implemented and is described here.

In the context of Igalia browser team effort to implement MathML support using TeX rules and OpenType features, I have started implementation of OpenType MATH support in HarfBuzz. This table from the OpenType standard is made of three subtables:

  • The MathConstants table, which contains layout constants. For example, the thickness of the fraction bar of <semantics>ab<annotation encoding="application/x-tex">\frac{a}{b}</annotation></semantics>.

  • The MathGlyphInfo table, which contains glyph properties. For instance, the italic correction indicating how slanted an integral is e.g. to properly place the subscript in <semantics>D<annotation encoding="application/x-tex">\displaystyle\displaystyle\int_{D}</annotation></semantics>.

  • The MathVariants table, which provides larger size variants for a base glyph or data to build a glyph assembly. For example, either a larger parenthesis or a assembly of U+239B, U+239C, U+239D to write something like:

      <semantics>(abcdefgh<annotation encoding="application/x-tex">\left(\frac{\frac{\frac{a}{b}}{\frac{c}{d}}}{\frac{\frac{e}{f}}{\frac{g}{h}}}\right.</annotation></semantics>  

Code to parse this table was added to Gecko and WebKit two years ago. The existing code to build glyph assembly in these Web engines was adapted to use the MathVariants data instead of only private tables. However, as we will see below the MathVariants data to build glyph assembly is more general, with arbitrary number of glyphs or with additional constraints on glyph overlaps. Also there are various fallback mechanisms for old fonts and other bugs that I think we could get rid of when we move to OpenType MATH fonts only.

In order to add MathML support in Blink, it is very easy to import the OpenType MATH parsing code from WebKit. However, after discussions with some Google developers, it seems that the best option is to directly add support for this table in HarfBuzz. Since this library is used by Gecko, by WebKit (at least the GTK port) and by many other applications such as Servo, XeTeX or LibreOffice it make senses to share the implementation to improve math rendering everywhere.

The idea for HarfBuzz is to add an API to

  1. 1.

    Expose data from the MathConstants and MathGlyphInfo.

  2. 2.

    Shape stretchy operators to some target size with the help of the MathVariants.

It is then up to a higher-level math rendering engine (e.g. TeX or MathML rendering engines) to beautifully display mathematical formulas using this API. The design choice for exposing MathConstants and MathGlyphInfo is almost obvious from the reading of the MATH table specification. The choice for the shaping API is a bit more complex and discussions is still in progress. For example because we want to accept stretching after glyph-level mirroring (e.g. to draw RTL clockwise integrals) we should accept any glyph and not just an input Unicode strings as it is the case for other HarfBuzz shaping functions. This shaping also depends on a stretching direction (horizontal/vertical) or on a target size (and Gecko even currently has various ways to approximate that target size). Finally, we should also have a way to expose italic correction for a glyph assembly or to approximate preferred width for Web rendering engines.

As I mentioned at the beginning, the data and algorithm to build glyph assembly is the most complex part of the OpenType MATH and deserves a special interest. The idea is that you have a list of <semantics>n1<annotation encoding="application/x-tex">n\geq 1</annotation></semantics> glyphs available to build the assembly. For each <semantics>0in-1<annotation encoding="application/x-tex">0\leq i\leq n-1</annotation></semantics>, the glyph <semantics>gi<annotation encoding="application/x-tex">g_{i}</annotation></semantics> has advance <semantics>ai<annotation encoding="application/x-tex">a_{i}</annotation></semantics> in the stretch direction. Each <semantics>gi<annotation encoding="application/x-tex">g_{i}</annotation></semantics> has straight connector part at its start (of length <semantics>si<annotation encoding="application/x-tex">s_{i}</annotation></semantics>) and at its end (of length <semantics>ei<annotation encoding="application/x-tex">e_{i}</annotation></semantics>) so that we can align the glyphs on the stretch axis and glue them together. Also, some of the glyphs are “extenders” which means that they can be repeated 0, 1 or more times to make the assembly as large as possible. Finally, the end/start connectors of consecutive glyphs must overlap by at least a fixed value <semantics>omin<annotation encoding="application/x-tex">o_{\mathrm{min}}</annotation></semantics> to avoid gaps at some resolutions but of course without exceeding the length of the corresponding connectors. This gives some flexibility to adjust the size of the assembly and get closer to the target size <semantics>t<annotation encoding="application/x-tex">t</annotation></semantics>.

<foreignObject color="#0000FF" width="16.19" height="100%">

<semantics>gi<annotation encoding="application/x-tex">g_{i}</annotation></semantics>

</foreignObject><foreignObject color="#0000FF" width="16.19" height="100%">

<semantics>si<annotation encoding="application/x-tex">s_{i}</annotation></semantics>

</foreignObject><foreignObject color="#0000FF" width="16.19" height="100%">

<semantics>ei<annotation encoding="application/x-tex">e_{i}</annotation></semantics>

</foreignObject><foreignObject color="#0000FF" width="16.19" height="100%">

<semantics>ai<annotation encoding="application/x-tex">a_{i}</annotation></semantics>

</foreignObject><foreignObject color="#FF0000" width="27.81" height="100%">

<semantics>gi+1<annotation encoding="application/x-tex">g_{i+1}</annotation></semantics>

</foreignObject><foreignObject color="#FF0000" width="27.81" height="100%">

<semantics>si+1<annotation encoding="application/x-tex">s_{i+1}</annotation></semantics>

</foreignObject><foreignObject color="#FF0000" width="27.81" height="100%">

<semantics>ei+1<annotation encoding="application/x-tex">e_{i+1}</annotation></semantics>

</foreignObject><foreignObject color="#FF0000" width="27.81" height="100%">

<semantics>ai+1<annotation encoding="application/x-tex">a_{i+1}</annotation></semantics>

</foreignObject><foreignObject color="#000000" width="39.43" height="100%">

<semantics>oi,i+1<annotation encoding="application/x-tex">o_{i,i+1}</annotation></semantics>

</foreignObject> Figure 0.1: Two adjacent glyphs in an assembly

To ensure that the width/height is distributed equally and the symmetry of the shape is preserved, the MATH table specification suggests the following iterative algorithm to determine the number of extenders and the connector overlaps to reach a minimal target size <semantics>t<annotation encoding="application/x-tex">t</annotation></semantics>:

  1. 1.

    Assemble all parts by overlapping connectors by maximum amount, and removing all extenders. This gives the smallest possible result.

  2. 2.

    Determine how much extra width/height can be distributed into all connections between neighboring parts. If that is enough to achieve the size goal, extend each connection equally by changing overlaps of connectors to finish the job.

  3. 3.

    If all connections have been extended to minimum overlap and further growth is needed, add one of each extender, and repeat the process from the first step.

We note that at each step, each extender is repeated the same number of times <semantics>r0<annotation encoding="application/x-tex">r\geq 0</annotation></semantics>. So if <semantics>IExt<annotation encoding="application/x-tex">I_{\mathrm{Ext}}</annotation></semantics> (respectively <semantics>INonExt<annotation encoding="application/x-tex">I_{\mathrm{NonExt}}</annotation></semantics>) is the set of indices <semantics>0in-1<annotation encoding="application/x-tex">0\leq i\leq n-1</annotation></semantics> such that <semantics>gi<annotation encoding="application/x-tex">g_{i}</annotation></semantics> is an extender (respectively is not an extender) we have <semantics>ri=r<annotation encoding="application/x-tex">r_{i}=r</annotation></semantics> (respectively <semantics>ri=1<annotation encoding="application/x-tex">r_{i}=1</annotation></semantics>). The size we can reach at step <semantics>r<annotation encoding="application/x-tex">r</annotation></semantics> is at most the one obtained with the minimal connector overlap <semantics>omin<annotation encoding="application/x-tex">o_{\mathrm{min}}</annotation></semantics> that is

<semantics>i=0N-1(j=1riai-omin)+omin=(iINonExtai-omin)+(iIExtr(ai-omin))+omin<annotation encoding="application/x-tex">\sum_{i=0}^{N-1}\left(\sum_{j=1}^{r_{i}}{a_{i}-o_{\mathrm{min}}}\right)+o_{% \mathrm{min}}=\left(\sum_{i\in I_{\mathrm{NonExt}}}{a_{i}-o_{\mathrm{min}}}% \right)+\left(\sum_{i\in I_{\mathrm{Ext}}}r{(a_{i}-o_{\mathrm{min}})}\right)+o% _{\mathrm{min}}</annotation></semantics>

We let <semantics>NExt=|IExt|<annotation encoding="application/x-tex">N_{\mathrm{Ext}}={|I_{\mathrm{Ext}}|}</annotation></semantics> and <semantics>NNonExt=|INonExt|<annotation encoding="application/x-tex">N_{\mathrm{NonExt}}={|I_{\mathrm{NonExt}}|}</annotation></semantics> be the number of extenders and non-extenders. We also let <semantics>SExt=iIExtai<annotation encoding="application/x-tex">S_{\mathrm{Ext}}=\sum_{i\in I_{\mathrm{Ext}}}a_{i}</annotation></semantics> and <semantics>SNonExt=iINonExtai<annotation encoding="application/x-tex">S_{\mathrm{NonExt}}=\sum_{i\in I_{\mathrm{NonExt}}}a_{i}</annotation></semantics> be the sum of advances for extenders and non-extenders. If we want the advance of the glyph assembly to reach the minimal size <semantics>t<annotation encoding="application/x-tex">t</annotation></semantics> then

  <semantics>SNonExt-omin(NNonExt-1)+r(SExt-ominNExt)t<annotation encoding="application/x-tex">{S_{\mathrm{NonExt}}-o_{\mathrm{min}}\left(N_{\mathrm{NonExt}}-1\right)}+{r% \left(S_{\mathrm{Ext}}-o_{\mathrm{min}}N_{\mathrm{Ext}}\right)}\geq t</annotation></semantics>  

We can assume <semantics>SExt-ominNExt>0<annotation encoding="application/x-tex">S_{\mathrm{Ext}}-o_{\mathrm{min}}N_{\mathrm{Ext}}>0</annotation></semantics> or otherwise we would have the extreme case where the overlap takes at least the full advance of each extender. Then we obtain

  <semantics>rrmin=max(0,t-SNonExt+omin(NNonExt-1)SExt-ominNExt)<annotation encoding="application/x-tex">r\geq r_{\mathrm{min}}=\max\left(0,\left\lceil\frac{t-{S_{\mathrm{NonExt}}+o_{% \mathrm{min}}\left(N_{\mathrm{NonExt}}-1\right)}}{S_{\mathrm{Ext}}-o_{\mathrm{% min}}N_{\mathrm{Ext}}}\right\rceil\right)</annotation></semantics>  

This provides a first simplification of the algorithm sketched in the MATH table specification: Directly start iteration at step <semantics>rmin<annotation encoding="application/x-tex">r_{\mathrm{min}}</annotation></semantics>. Note that at each step we start at possibly different maximum overlaps and decrease all of them by a same value. It is not clear what to do when one of the overlap reaches <semantics>omin<annotation encoding="application/x-tex">o_{\mathrm{min}}</annotation></semantics> while others can still be decreased. However, the sketched algorithm says all the connectors should reach minimum overlap before the next increment of <semantics>r<annotation encoding="application/x-tex">r</annotation></semantics>, which means the target size will indeed be reached at step <semantics>rmin<annotation encoding="application/x-tex">r_{\mathrm{min}}</annotation></semantics>.

One possible interpretation is to stop overlap decreasing for the adjacent connectors that reached minimum overlap and to continue uniform decreasing for the others until all the connectors reach minimum overlap. In that case we may lose equal distribution or symmetry. In practice, this should probably not matter much. So we propose instead the dual option which should behave more or less the same in most cases: Start with all overlaps set to <semantics>omin<annotation encoding="application/x-tex">o_{\mathrm{min}}</annotation></semantics> and increase them evenly to reach a same value <semantics>o<annotation encoding="application/x-tex">o</annotation></semantics>. By the same reasoning as above we want the inequality

  <semantics>SNonExt-o(NNonExt-1)+rmin(SExt-oNExt)t<annotation encoding="application/x-tex">{S_{\mathrm{NonExt}}-o\left(N_{\mathrm{NonExt}}-1\right)}+{r_{\mathrm{min}}% \left(S_{\mathrm{Ext}}-oN_{\mathrm{Ext}}\right)}\geq t</annotation></semantics>  

which can be rewritten

  <semantics>SNonExt+rminSExt-o(NNonExt+rminNExt-1)t<annotation encoding="application/x-tex">S_{\mathrm{NonExt}}+r_{\mathrm{min}}S_{\mathrm{Ext}}-{o\left(N_{\mathrm{NonExt% }}+{r_{\mathrm{min}}N_{\mathrm{Ext}}}-1\right)}\geq t</annotation></semantics>  

We note that <semantics>N=NNonExt+rminNExt<annotation encoding="application/x-tex">N=N_{\mathrm{NonExt}}+{r_{\mathrm{min}}N_{\mathrm{Ext}}}</annotation></semantics> is just the exact number of glyphs used in the assembly. If there is only a single glyph, then the overlap value is irrelevant so we can assume <semantics>NNonExt+rNExt-1=N-11<annotation encoding="application/x-tex">N_{\mathrm{NonExt}}+{rN_{\mathrm{Ext}}}-1=N-1\geq 1</annotation></semantics>. This provides the greatest theorical value for the overlap <semantics>o<annotation encoding="application/x-tex">o</annotation></semantics>:

  <semantics>ominoomaxtheorical=SNonExt+rminSExt-tNNonExt+rminNExt-1<annotation encoding="application/x-tex">o_{\mathrm{min}}\leq o\leq o_{\mathrm{max}}^{\mathrm{theorical}}=\frac{S_{% \mathrm{NonExt}}+r_{\mathrm{min}}S_{\mathrm{Ext}}-t}{N_{\mathrm{NonExt}}+{r_{% \mathrm{min}}N_{\mathrm{Ext}}}-1}</annotation></semantics>  

Of course, we also have to take into account the limit imposed by the start and end connector lengths. So <semantics>omax<annotation encoding="application/x-tex">o_{\mathrm{max}}</annotation></semantics> must also be at most <semantics>min(ei,si+1)<annotation encoding="application/x-tex">\min{(e_{i},s_{i+1})}</annotation></semantics> for <semantics>0in-2<annotation encoding="application/x-tex">0\leq i\leq n-2</annotation></semantics>. But if <semantics>rmin2<annotation encoding="application/x-tex">r_{\mathrm{min}}\geq 2</annotation></semantics> then extender copies are connected and so <semantics>omax<annotation encoding="application/x-tex">o_{\mathrm{max}}</annotation></semantics> must also be at most <semantics>min(ei,si)<annotation encoding="application/x-tex">\min{(e_{i},s_{i})}</annotation></semantics> for <semantics>iIExt<annotation encoding="application/x-tex">i\in I_{\mathrm{Ext}}</annotation></semantics>. To summarize, <semantics>omax<annotation encoding="application/x-tex">o_{\mathrm{max}}</annotation></semantics> is the minimum of <semantics>omaxtheorical<annotation encoding="application/x-tex">o_{\mathrm{max}}^{\mathrm{theorical}}</annotation></semantics>, of <semantics>ei<annotation encoding="application/x-tex">e_{i}</annotation></semantics> for <semantics>0in-2<annotation encoding="application/x-tex">0\leq i\leq n-2</annotation></semantics>, of <semantics>si<annotation encoding="application/x-tex">s_{i}</annotation></semantics> <semantics>1in-1<annotation encoding="application/x-tex">1\leq i\leq n-1</annotation></semantics> and possibly of <semantics>e0<annotation encoding="application/x-tex">e_{0}</annotation></semantics> (if <semantics>0IExt<annotation encoding="application/x-tex">0\in I_{\mathrm{Ext}}</annotation></semantics>) and of of <semantics>sn-1<annotation encoding="application/x-tex">s_{n-1}</annotation></semantics> (if <semantics>n-1IExt<annotation encoding="application/x-tex">{n-1}\in I_{\mathrm{Ext}}</annotation></semantics>).

With the algorithm described above <semantics>NExt<annotation encoding="application/x-tex">N_{\mathrm{Ext}}</annotation></semantics>, <semantics>NNonExt<annotation encoding="application/x-tex">N_{\mathrm{NonExt}}</annotation></semantics>, <semantics>SExt<annotation encoding="application/x-tex">S_{\mathrm{Ext}}</annotation></semantics>, <semantics>SNonExt<annotation encoding="application/x-tex">S_{\mathrm{NonExt}}</annotation></semantics> and <semantics>rmin<annotation encoding="application/x-tex">r_{\mathrm{min}}</annotation></semantics> and <semantics>omax<annotation encoding="application/x-tex">o_{\mathrm{max}}</annotation></semantics> can all be obtained using simple loops on the glyphs <semantics>gi<annotation encoding="application/x-tex">g_{i}</annotation></semantics> and so the complexity is <semantics>O(n)<annotation encoding="application/x-tex">O(n)</annotation></semantics>. In practice <semantics>n<annotation encoding="application/x-tex">n</annotation></semantics> is small: For existing fonts, assemblies are made of at most three non-extenders and two extenders that is <semantics>n5<annotation encoding="application/x-tex">n\leq 5</annotation></semantics> (incidentally, Gecko and WebKit do not currently support larger values of <semantics>n<annotation encoding="application/x-tex">n</annotation></semantics>). This means that all the operations described above can be considered to have constant complexity. This is much better than a naive implementation of the iterative algorithm sketched in the OpenType MATH table specification which seems to require at worst

  <semantics>r=0rmin-1NNonExt+rNExt=NNonExtrmin+rmin(rmin-1)2NExt=O(n×rmin2)<annotation encoding="application/x-tex">\sum_{r=0}^{r_{\mathrm{min}}-1}{N_{\mathrm{NonExt}}+rN_{\mathrm{Ext}}}=N_{% \mathrm{NonExt}}r_{\mathrm{min}}+\frac{r_{\mathrm{min}}\left(r_{\mathrm{min}}-% 1\right)}{2}N_{\mathrm{Ext}}={O(n\times r_{\mathrm{min}}^{2})}</annotation></semantics>  

and at least <semantics>Ω(rmin)<annotation encoding="application/x-tex">\Omega(r_{\mathrm{min}})</annotation></semantics>.

One of issue is that the number of extender repetitions <semantics>rmin<annotation encoding="application/x-tex">r_{\mathrm{min}}</annotation></semantics> and the number of glyphs in the assembly <semantics>N<annotation encoding="application/x-tex">N</annotation></semantics> can become arbitrary large since the target size <semantics>t<annotation encoding="application/x-tex">t</annotation></semantics> can take large values e.g. if one writes \underbrace{\hspace{65535em}} in LaTeX. The improvement proposed here does not solve that issue since setting the coordinates of each glyph in the assembly and painting them require <semantics>Θ(N)<annotation encoding="application/x-tex">\Theta(N)</annotation></semantics> operations as well as (in the case of HarfBuzz) a glyph buffer of size <semantics>N<annotation encoding="application/x-tex">N</annotation></semantics>. However, such large stretchy operators do not happen in real-life mathematical formulas. Hence to avoid possible hangs in Web engines a solution is to impose a maximum limit <semantics>Nmax<annotation encoding="application/x-tex">N_{\mathrm{max}}</annotation></semantics> for the number of glyph in the assembly so that the complexity is limited by the size of the DOM tree. Currently, the proposal for HarfBuzz is <semantics>Nmax=128<annotation encoding="application/x-tex">N_{\mathrm{max}}=128</annotation></semantics>. This means that if each assembly glyph is 1em large you won’t be able to draw stretchy operators of size more than 128em, which sounds a quite reasonable bound. With the above proposal, <semantics>rmin<annotation encoding="application/x-tex">r_{\mathrm{min}}</annotation></semantics> and so <semantics>N<annotation encoding="application/x-tex">N</annotation></semantics> can be determined very quickly and the cases <semantics>NNmax<annotation encoding="application/x-tex">N\geq N_{\mathrm{max}}</annotation></semantics> rejected, so that we avoid losing time with such edge cases…

Finally, because in our proposal we use the same overlap <semantics>o<annotation encoding="application/x-tex">o</annotation></semantics> everywhere an alternative for HarfBuzz would be to set the output buffer size to <semantics>n<annotation encoding="application/x-tex">n</annotation></semantics> (i.e. ignore <semantics>r-1<annotation encoding="application/x-tex">r-1</annotation></semantics> copies of each extender and only keep the first one). This will leave gaps that the client can fix by repeating extenders as long as <semantics>o<annotation encoding="application/x-tex">o</annotation></semantics> is also provided. Then HarfBuzz math shaping can be done with a complexity in time and space of just <semantics>O(n)<annotation encoding="application/x-tex">O(n)</annotation></semantics> and it will be up to the client to optimize or limit the painting of extenders for large values of <semantics>N<annotation encoding="application/x-tex">N</annotation></semantics>

By fredw at April 16, 2016 09:23 PM

April 13, 2016

Release Notes for Safari Technology Preview 2

WebKit Blog

Safari Technology Preview Release 2 is now available for download. If you already have Safari Technology Preview installed, you can update from the Mac App Store’s Updates tab. Release 2 of Safari Technology Preview covers WebKit revisions 198530–199085.

Browser Differences

  • Changed the CFBundleSignature to allow Apple Events, like those sent from AppleScript, to correctly distinguish between Safari and Safari Technology Preview

JavaScript

  • Added ES6 support for Symbol.isConcatSpreadable (r198808)
  • Disallowed var assignments in for-in loops according to ES6 specs (r198928)
  • Improved stability for ES6 classes when invoking a method of the parent class before calling super() in a constructor (r198714)
  • Allowed undefined or null for Symbol.search and Symbol.match (r198581)
  • Enabled Array.prototype native functions’ species constructors to work with proxies (r198589)
  • Implemented the proposal for String.prototype.padStart() and String.prototype.padEnd() (r198674)
  • Implemented ES6 spec for String.prototype.match and RegExp.prototype[@@match] (r198554)
  • Included a workaround for web compatibility on ES6 TypeErrors when accessing RegExp.prototype flag properties (r198698)
  • Corrected quantified unicode regular expressions (r198866)
  • Ensured greedy unicode regular expressions properly backtrack past non-BMP characters (r198624)

CSS

  • Implemented the allow-end value of the hanging-punctuation CSS property (r198683)
  • Improved web compatibility by resetting CSS spacing rules on <math> elements (r198952)
  • Added the new color-gamut CSS media query (r199024)
  • Updated screen queries to check the capabilities of the current screen instead of the deepest available screen (r198595)

Web APIs

  • Restricted WebSockets header parsing according to RFC6455 and RFC7230 (r198561)
  • Improved performance of certain draw calls in WebGL with a non-power-of-two texture optimization (r198588)
  • Disabled the Fetch API until the implementation is ready to be enabled by default (r199081)
  • Enhanced Shadow DOM support to compute styles for the style attribute of <slot> elements (r198990)
  • Softened pushState and replaceState frequency restrictions (r198687)

Web Inspector

  • Timelines tab performance and bug fixes (r198550, r198563, r198601, r198602, r198603, r198618, r198620, r198745, r199077, r199085)
  • Disabled debugger statements and breakpoints while profiling a page to ensure maximum performance accuracy (r198648)
  • Added the ability to configure timeline instruments to use for recordings (r198537)
  • Added a paint count indicator in the top left corner of non-opaque layers (r198599)
  • Added font-variant-numeric to CSS autocompletions (r198750)
  • Added the console.takeHeapSnapshot method for capturing heap snapshots (r198786)
  • Changed details sidebar shortcuts to Command-Option-0 and Command-Shift-0 (r199082)
  • Double-quotes and backslashes in strings are now displayed correctly in the console (r198585)
  • Improved the consistency of CSP directive violation messages reported in the console (r198591)

Accessibility

  • Corrected new lines in content editable elements to notify accessibility (r199030)
  • Updated the handling of SVG elements with a presentational role to be the same as other host language elements (r198870)
  • Limited the numbered list announcement for a list item number to the first line of text in the list item (r198806)
  • Changed the accessibility role descriptions for JavaScript alerts to “web dialog” and “web alert dialog” to make them more understandable to screen reader users (r198543)

Rendering

  • Updated backdrop filter to repaint when changed in JavaScript (r198963)
  • Corrected drawing SVG stroke patterns for objects with empty bounding box elements (r198574)

Media

  • Improved stability when an audio source is changed while being processed (r198654)
  • Fixed audio track listings (r198703)

Networking

  • Improved the reliability of speculative disk cache validation requests with the HTTP Referer header (r198741)

Bug Fixes

  • Fixed autoscrolling in a drag selection when a window is against the screen edge, including while in full screen mode (r198692)

Sharing Your Feedback

You can file bugs or feature requests at the WebKit bug tracker, or you can submit feedback or bugs to Apple on Apple’s bug reporting website. For other questions or feedback, feel free to reach us on Twitter at @webkit or Jonathan Davis at @jonathandavis.

By Jon Davis at April 13, 2016 05:10 PM

March 31, 2016

Michael Catanzaro: Positive progress on WebKitGTK+ security updates

Igalia WebKit

I previously reported that, although WebKitGTK+ releases regular upstream security updates, most Linux distributions are not taking the updates. At the time, only Arch Linux and Fedora were reliably releasing our security updates. So I’m quite pleased that openSUSE recently released a WebKitGTK+ security update, and then Mageia did too. Gentoo currently has an update in the works. It remains to be seen if these distros regularly follow up on updates (expect a follow-up post on this in a few months), but, optimistically, you now have several independent distros to choose from to get an updated version WebKitGTK+, plus any distros that regularly receive updates directly from these distros.

Unfortunately, not all is well yet. It’s still not safe to use WebKitGTK+ on the latest releases of Debian or Ubuntu, or on derivatives like Linux Mint, elementary OS, or Raspbian. (Raspbian is notable because it uses an ancient, insecure version of Epiphany as its default web browser, and Raspberry Pis are kind of popular.)

And of course, no distribution has been able to get rid of old, insecure WebKitGTK+ 2.4 compatibility packages, so many applications on distributions that do provide security updates for modern WebKitGTK+ will still be insecure. (Don’t be fooled by the recent WebKitGTK+ 2.4.10 update; it contains only a few security fixes that were easy to backport, and was spurred by the need to add GTK+ 3.20 compatibility. It is still not safe to use.) Nor have distributions managed to remove QtWebKit, which is also old and insecure. You still need to check individual applications to see if they are running safe versions of WebKit.

But at least there are now several distros providing WebKitGTK+ security updates. That’s good.

Special thanks to Apple and to my colleagues at Igalia for their work on the security advisories that motivate these updates.

By Michael Catanzaro at March 31, 2016 03:00 AM

Michael Catanzaro: Epiphany 3.20

Igalia WebKit

So, what’s new in Epiphany 3.20?

First off: overlay scrollbars. Because web sites have the ability to style their scrollbars (which you’ve probably noticed on Google sites), WebKit embedders cannot use a normal GtkScrolledWindow to display content; instead, WebKit has to paint the scrollbars itself. Hence, when overlay scrollbars appeared in GTK+ 3.16, WebKit applications were left out. Carlos García Campos spent some time to work on this, and the result speaks for itself (if you fullscreen this video to see it properly):

Overlay scrollbars did not actually require any changes in Epiphany itself — all applications using an up-to-date version of WebKit will immediately benefit — but I mention it here as it’s one of the most noticeable changes. Read about other WebKit improvements, like the new Faster Than Light FTL/B3 JavaScript compilation tier, on Carlos’s blog.

Next up, there is a new downloads manager, also by Carlos García Campos. This replaces the old downloads bar that used to appear at the bottom of the screen:

Screenshot of the new downloads manager in Epiphany 3.20.

I flipped the switch in Epiphany to enable WebGL:

If you watched that video in fullscreen, you might have noticed that page is marked as insecure, even though it doesn’t use HTTPS. Like most browsers, we used to have several confusing security states. Pages with mixed content received a security warning that all users ignored, but pages with no security at all received no such warning. That’s pretty dumb, which is why Firefox and Chrome have been talking about changing this for a year or so now. I went ahead and implemented it. We now have exactly two security states: secure and insecure. If your page loads any content not over HTTPS, it will be marked as insecure. The vast majority of pages will be displayed as insecure, but it’s no less than such sites deserve. I’m not concerned at all about “warning fatigue,” because users are not generally expected to take any action on seeing these warnings. In the future, we will take this further, and use the insecure indicator for sites that use SHA-1 certificates.

Moving on. By popular request, I exposed the previously-hidden setting to disable session restore in the preferences dialog, as “Remember previous tabs on startup:”

Screenshot of the preferences dialog, with the new

Meanwhile, Carlos worked in both WebKit and Epiphany to greatly improve session restoration. Previously, Epiphany would save the URLs of the pages loaded in each tab, and when started it would load each URL in a new tab, but you wouldn’t have any history for those tabs, for example, and the state of the tab would otherwise be lost. Carlos worked on serializing the WebKit session state and exposing it in the WebKitGTK+ API, allowing us to restore full back/forward history for each tab, plus details like your scroll position on each tab. Thanks to Carlos, we also now make use of this functionality when reopening closed tabs, so your reopened tab will have a full back/forward list of history, and also when opening new tabs, so the new tab will inherit the history of the tab it was opened from (a feature that we had in the past, but lost when we switched to WebKit2).

Interestingly, we found the session restoration was at first too good: it would restore the page really exactly as you last viewed it, without refreshing the content at all. This means that if, for example, you were viewing a page in Bugzilla, then when starting the browser, you would miss any new comments from the last time you loaded the page until you refresh the page manually. This is actually the current behavior in Safari; it’s desirable on iOS to make the browser launch instantly, but questionable for desktop Safari. Carlos decided to always refresh the page content when restoring the session for WebKitGTK+.

Last, and perhaps least, there’s a new empty state displayed for new users, developed by Lorenzo Tilve and polished up by me, so that we don’t greet new users with a completely empty overview (where your most-visited sites are normally displayed):

Empty State

That, plus a bundle of the usual bugfixes, significant code cleanups, and internal architectual improvements (e.g. I converted the communication between the UI process and the web process extension to use private D-Bus connections instead of the session bus). The best things have not changed: it still starts up about 5-20 times faster than Firefox in my unscientific testing; I expect you’ll find similar results.

Enjoy!

By Michael Catanzaro at March 31, 2016 01:54 AM

March 30, 2016

Introducing Safari Technology Preview

WebKit Blog

safari

Starting today, there’s a new, convenient way to see what features and improvements are coming to Safari and other applications that use WebKit. Safari Technology Preview is a version of Safari for OS X, distributed by Apple, that includes a cutting-edge, in-development version of the WebKit browser engine. It’s a great way to test upcoming WebKit features and give feedback to the people building them when it’s most useful — early in development.

Safari Technology Preview is a standalone application that can be used side-by-side with Safari or other web browsers, making it easy to compare behaviors between them. Besides having the latest web features and bug fixes from WebKit, Safari Technology Preview includes the latest improvements to Web Inspector, which you can use to develop and debug your websites. Updates for Safari Technology Preview will be available every two weeks through the Updates pane of the Mac App Store.

How to Get It

You can download Safari Technology Preview from Apple’s Developer website. No account is required to download. You only need to install it once; afterward, updates will be delivered through the App Store.

Features You Can Try Today

Here are just a few areas of recent developments in WebKit that you can try in Safari Technology Preview today.

ECMAScript 6

Safari Technology Preview supports ECMAScript 6, the latest iteration of the JavaScript programming language. ES6 has many new features, including classes; lexical scoping using let, const, and class; iterators and generators; arrow functions; default parameters values; and many new built-in APIs.

B3 JavaScript JIT compiler

B3 is a new low-latency, high-throughput compiler designed from the ground up to support JavaScript and other dynamic languages. B3 delivers great performance benefits, especially on systems with fewer CPU cores.

Improved IndexedDB implementation

WebKit’s revamped IndexedDB implementation is more stable, more standards compliant, and still undergoing rapid improvement.

Shadow DOM

The latest version of Shadow DOM has been heavily revised based on input from web content authors and browser developers. WebKit is the first browser engine to implement this new version of the Shadow DOM spec.

Programmatic cut and copy to the clipboard

It’s now possible to programmatically copy and cut text in response to a user gesture with document.execCommand('copy') and document.execCommand('cut'). Having this ability may eliminate some websites’ last need for the Flash plug-in.

Content Security Policy Level 2

You can define a policy for your web application to mitigate content injection vulnerabilities, such as cross-site scripting (XSS). Level 2 expands on Level 1 with support for <script> and <style> hashes, nonces, and new policy directives to control which websites can embed your web content.

What about the WebKit Nightly?

You may already be familiar with the WebKit Nightly, which serves a purpose similar to that of Safari Technology Preview. For most people, we think Safari Technology Preview is a more convenient and stable way to live on recent WebKit changes. Unlike the nightlies, Safari Technology Preview supports the full set of iCloud-based Safari features, including iCloud History and iCloud Tabs. And we’ll use the time between Safari Technology Preview releases to curate and test updates to a point where we think developers will find it practical to use as their primary browser.

Sharing Your Feedback

We want to hear your feedback about WebKit features before Safari ships them. Your requests and experiences help the WebKit project figure out what’s most important, and the stories of your successes or struggles with features help us refine our implementations. Hearing from the community earlier will give us more perspectives to consider, with more time to act on what we’ve learned.

You can file bugs or feature requests at the WebKit bug tracker, or you can submit feedback or bugs to Apple on Apple’s bug reporting website. For other questions or feedback, feel free to reach me on Twitter at @rmondello or Jonathan Davis at @jonathandavis.

By Ricky Mondello at March 30, 2016 05:00 PM

March 28, 2016

New Web Features in Safari

WebKit Blog

Last week, a new version of Safari shipped with the release of iOS 9.3 and OS X El Capitan 10.11.4. Safari on iOS 9.3 and Safari 9.1 on OS X are significant releases that incorporate a lot of exciting web features from WebKit. These are web features that were considered ready to go, and we simply couldn’t wait to share them with users and developers alike.

On top of new web features, this release improves the way people experience the web with more responsiveness on iOS, new gestures on OS X, and safer JavaScript dialogs. Developers will appreciate the extra polish, performance and new tools available in Web Inspector.

Here is a brief review of what makes this release so significant.

Web Features

Picture Element

The <picture> element is a container that is used to group different <source> versions of the same image. It offers a fallback approach so the browser can choose the right image depending on device capabilities, like pixel density and screen size. This comes in handy for using new image formats with built-in graceful degradation to well-supported image formats. The ability to specify media queries in the media attribute on the <source> elements brings art direction of images to responsive web design.

For more on the <picture> element, take a look at the HTML 5.1 spec.

CSS Variables

CSS variables, known formally as CSS Custom Properties, let developers reduce code duplication, code complexity and make maintenance of CSS much easier. Recently we talked about how Web Inspector took advantage of CSS variables, to reduce code duplication and shed many CSS rules.

You can read more about CSS Variables in WebKit.

Font Features

CSS font features allow you to use special text styles and effects available in fonts like ligatures and small caps. These aren’t faux representations manufactured by the browser, but the intended styles designed by the font author.

For more information, read the CSS Font Features blog post.

Will Change Property

The CSS will-change property lets you tell the browser ahead of time about changes that are likely to happen on an element. The hint gives browsers a heads-up so that they can make engine optimizations to deliver smooth performance.

Read more about will-change in the CSS Will Change Module Level 1 spec.

Gesture Events for OS X

Already available in WebKit for iOS, gesture events are supported on OS X with Safari 9.1. Gesture events are used to detect pinching and rotation on trackpads.

See the GestureEvent Class Reference for more details.

Browsing Improvements

Fast-Tap on iOS

WebKit for iOS has a 350 millisecond delay to allow detecting double-tapping to zoom content that appears too small on mobile devices. With the release of Safari 9.1, WebKit on iOS removes the delay for web content that is designed for the mobile viewport size.

Read about More Responsive Tapping on iOS for details on how to ensure web pages can get this fast-tap behavior.

JavaScript Dialogs

To protect users from bad actors using JavaScript dialogs in unscrupulous ways, the dialogs in Safari 9.1 were redesigned to look and work more like web content. The new behavior means that dialogs no longer prevent a user from navigating away or closing the page. Instead users can more clearly understand the dialogs come from the web page they are viewing and easily dismiss them.

For more details, see the Displaying Dialogs section from What’s New in Safari.

Web Inspector Improvements

Web developers will enjoy several new noteworthy enhancements to debugging and styling with Web Inspector. Faster performance in timelines means debugging complex pages and web apps is easier than ever. The new Watch Expressions section in the Scope Chain sidebar helps a developer to see the data flowing through the JavaScript environment.

In the Elements tab, pseudo-elements such as ::before and ::after are accessible from the DOM tree to make it straightforward to inspect and style them.

Web Inspector also added a Visual Styles sidebar that adds visual tools for modifying webpage styles without requiring memorization of all of the properties and elements of CSS. It makes styling a web page more accessible to designers and developers alike, allowing them to get involved in exploring different styles.

Learn more about how it works in Editing CSS with the Visual Styles Sidebar.

Feedback

That is a lot of enhancements and refinements for a dot-release. Along with OS X El Capitan, Safari 9.1 is also available on OS X Yosemite and OS X Mavericks — bringing all of these improvements to even more users. We’d love to hear about your favorite new feature. Please send your tweets to @webkit or @jonathandavis and let us know!

By Jon Davis at March 28, 2016 02:00 PM

March 23, 2016

CSS Variables in WebKit

WebKit Blog

CSS variables, properly known as CSS Custom Properties, were added to WebKit in the fall of 2015. WebKit has always been intrigued by the idea of putting variables in CSS, ever since 2008 when Dave Hyatt added our first experimental implementation. Since then there were two more re-writes of CSS Custom Properties, which helped shape the standard that browser vendors are settling on today.

CSS variables allow exactly what developers expect, assigning a value to a custom CSS symbol that can be re-used in the stylesheets of a web page. CSS quickly becomes complicated and often requires a lot of repetitive code, so the benefits of variables are obvious. Variables make it possible to reduce the amount of duplicate code and simplify the maintenance of complex CSS systems.

Developers have enjoyed variable-like features in their CSS for years using pre-processors as part of a web development tool chain. Unlike pre-processors though, native CSS variables bring dynamic variables to the mostly static syntax of CSS. CSS variables are, in fact, custom CSS properties that have DOM context. This is an important characteristic that allows CSS Custom Properties to do things you can’t do with variables in pre-processors. These are live properties that can mutate depending on the cascade of rules. Understanding this nuanced difference unlocks the full potential that CSS Custom Properties provides.

Custom Property Syntax

At first glance the syntax may seem a little strange compared to variable syntax in other languages. It is designed to fit within the existing CSS grammar using a shorthand prefix. To define a custom property, create a CSS element rule and within it add a custom property name with a double-dash prefix:

#foo {
   --default-color: #08c;
}

Generally, you’ll define the default values for custom properties using the :root pseudo-selector so that they are available everywhere:

:root {
   --default-color: #08c;
}

To use the variable property, use the var() function passing the custom property name and optionally a fallback value in cases where the custom property may not be available:

#foo h1 {
    color: var(--default-color, black);
}

Since the var() function produces a value, it can be used in place of any value, such as inside of other CSS functions like calc() or linear-gradient().

.gradient {
    width: 66%;
    height: 240px;
    background: linear-gradient(120deg, rgb(100, 0, var(--less-blue, 255)), rgb(100, 255, var(--more-blue, 0)));
}

.gradient:hover {
    --less-blue: 100;
    --more-blue: 255;
}
Hover over the gradients to apply the custom properties

In the above figure, the custom properties are applied to only one gradient at a time following the normal rules of :hover behavior.

CSS custom properties can also be accessed in JavaScript:

element.style.getPropertyValue('--less-blue');

It’s worth noting that the above JavaScript provides the inherited custom property value for element, not necessarily the value set in a :root pseudo-selector rule. To get a custom property value set on the root element, get the styles applied to document.documentElement:

var rootStyles = getComputedStyle(document.documentElement);
var defaultColor = rootStyles.getPropertyValue('--default-color');

Since these are runtime properties, values can be updated dynamically:

element.style.setProperty('--less-blue', '75');
document.documentElement.style.setProperty('--default-color', '#c80');

Simplifying Web Inspector

For a real world example, look no further than Web Inspector in WebKit where using CSS Custom Properties made it possible to simplify styling, trim some complex CSS rules, and make future maintenance easier. That’s a lot of wins that wouldn’t have been possible to the same degree using CSS pre-processor variables.

Being a web app, the interface of Web Inspector is driven by web technologies, but it’s designed to look and work like an app native to the OS. To maintain the user experience when Web Inspector is in a window, the native window behaviors need to be emulated. For example, when the window changes state from active to inactive the look of the window controls and frame elements need to simulate what a native inactive window would do — diminish the window’s visual impact by reducing contrast.

Active and inactive OS X windows

To achieve this effect, the CSS of Web Inspector keys off of a window-inactive class with rules that override the normal appearance. The override rules change colors to reduce the contrast. Before CSS Custom Properties, there was no single-rule approach to override the colors on all of the properties for all of the elements that need adjusted. The approach consisted of a rule for an element that sets a normal active-state color along with an override rule when a window-inactive class is set on the document body to subtly change the color.

.sidebar.left {
    border-right: 1px solid hsl(0, 0%, 70%);
}

.sidebar.right {
    border-left: 1px solid hsl(0, 0%, 70%);
}

body.window-inactive .sidebar.left {
    border-right-color: hsl(0, 0%, 85%);
}

body.window-inactive .sidebar.right {
    border-left-color: hsl(0, 0%, 85%);
}

What CSS Custom Properties allows instead is one override to rule them all. The default state has an initial custom property definition, then changes the custom property value for the new window state directly:

:root {
    --border-color: hsl(0, 0%, 70%);
}

body.window-inactive { 
    --border-color: hsl(0, 0%, 85%); 
}

This allows inheritance to do all of the work so that element-specific state overrides can be dropped in favor of simply referencing the variable custom property.

.sidebar.left {
    border-right: 1px solid var(--border-color);
}

.sidebar.right {
    border-left: 1px solid var(--border-color);
}

The 4-line change to declare CSS variables in Web Inspector replaced 32 duplicated color values with var(--border-color) and eliminated 23 rules at the same time!

Takeaways

CSS Custom Properties unlock better techniques for architecting stylesheets that can dramatically reduce CSS code used, and make management of large CSS systems far easier. Controlling thematic color changes is just a starting point. Imagine the possibilities of cascading dynamic variables for managing fonts, spacing, backgrounds, element positions, or naming custom transition timing curves.

Feedback

You can try out CSS Custom Properties in the WebKit Nightly Build or in Safari 9.1 on iOS 9.3, and OS X El Capitan 10.11.4, Yosemite, and Mavericks. Let us know how you’re using CSS Custom Properties and send feedback on Twitter (@webkit, @jonathandavis) or by filing a bug.

By Jon Davis at March 23, 2016 02:00 PM

March 22, 2016

Carlos García Campos: WebKitGTK+ 2.12

Igalia WebKit

We did it again, the Igalia WebKit team is pleased to announce a new stable release of WebKitGTK+, with a bunch of bugs fixed, some new API bits and many other improvements. I’m going to talk here about some of the most important changes, but as usual you have more information in the NEWS file.

FTL

FTL JIT is a JavaScriptCore optimizing compiler that was developed using LLVM to do low-level optimizations. It’s been used by the Mac port since 2014 but we hadn’t been able to use it because it required some patches for LLVM to work on x86-64 that were not included in any official LLVM release, and there were also some crashes that only happened in Linux. At the beginning of this release cycle we already had LLVM 3.7 with all the required patches and the crashes had been fixed as well, so we finally enabled FTL for the GTK+ port. But in the middle of the release cycle Apple surprised us announcing that they had the new FTL B3 backend ready. B3 replaces LLVM and it’s entirely developed inside WebKit, so it doesn’t require any external dependency. JavaScriptCore developers quickly managed to make B3 work on Linux based ports and we decided to switch to B3 as soon as possible to avoid making a new release with LLVM to remove it in the next one. I’m not going to enter into the technical details of FTL and B3, because they are very well documented and it’s probably too boring for most of the people, the key point is that it improves the overall JavaScript performance in terms of speed.

Persistent GLib main loop sources

Another performance improvement introduced in WebKitGTK+ 2.12 has to do with main loop sources. WebKitGTK+ makes an extensive use the GLib main loop, it has its own RunLoop abstraction on top of GLib main loop that is used by all secondary processes and most of the secondary threads as well, scheduling main loop sources to send tasks between threads. JavaScript timers, animations, multimedia, the garbage collector, and many other features are based on scheduling main loop sources. In most of the cases we are actually scheduling the same callback all the time, but creating and destroying the GSource each time. We realized that creating and destroying main loop sources caused an overhead with an important impact in the performance. In WebKitGTK+ 2.12 all main loop sources were replaced by persistent sources, which are normal GSources that are never destroyed (unless they are not going to be scheduled anymore). We simply use the GSource ready time to make them active/inactive when we want to schedule/stop them.

Overlay scrollbars

GNOME designers have requested us to implement overlay scrollbars since they were introduced in GTK+, because WebKitGTK+ based applications didn’t look consistent with all other GTK+ applications. Since WebKit2, the web view is no longer a GtkScrollable, but it’s scrollable by itself using native scrollbars appearance or the one defined in the CSS. This means we have our own scrollbars implementation that we try to render as close as possible to the native ones, and that’s why it took us so long to find the time to implement overlay scrollbars. But WebKitGTK+ 2.12 finally implements them and are, of course, enabled by default. There’s no API to disable them, but we honor the GTK_OVERLAY_SCROLLING environment variable, so they can be disabled at runtime.

But the appearance was not the only thing that made our scrollbars inconsistent with the rest of the GTK+ applications, we also had a different behavior regarding the actions performed for mouse buttons, and some other bugs that are all fixed in 2.12.

The NetworkProcess is now mandatory

The network process was introduced in WebKitGTK+ since version 2.4 to be able to use multiple web processes. We had two different paths for loading resources depending on the process model being used. When using the shared secondary process model, resources were loaded by the web process directly, while when using the multiple web process model, the web processes sent the requests to the network process for being loaded. The maintenance of this two different paths was not easy, with some bugs happening only when using one model or the other, and also the network process gained features like the disk cache that were not available in the web process. In WebKitGTK+ 2.12 the non network process path has been removed, and the shared single process model has become the multiple web process model with a limit of 1. In practice it means that a single web process is still used, but the network happens in the network process.

NPAPI plugins in Wayland

I read it in many bug reports and mailing lists that NPAPI plugins will not be supported in wayland, so things like http://extensions.gnome.org will not work. That’s not entirely true. NPAPI plugins can be windowed or windowless. Windowed plugins are those that use their own native window for rendering and handling events, implemented in X11 based systems using XEmbed protocol. Since Wayland doesn’t support XEmbed and doesn’t provide an alternative either, it’s true that windowed plugins will not be supported in Wayland. Windowless plugins don’t require any native window, they use the browser window for rendering and events are handled by the browser as well, using X11 drawable and X events in X11 based systems. So, it’s also true that windowless plugins having a UI will not be supported by Wayland either. However, not all windowless plugins have a UI, and there’s nothing X11 specific in the rest of the NPAPI plugins API, so there’s no reason why those can’t work in Wayland. And that’s exactly the case of http://extensions.gnome.org, for example. In WebKitGTK+ 2.12 the X11 implementation of NPAPI plugins has been factored out, leaving the rest of the API implementation common and available to any window system used. That made it possible to support windowless NPAPI plugins with no UI in Wayland, and any other non X11 system, of course.

New API

And as usual we have completed our API with some new additions:

 

By carlos garcia campos at March 22, 2016 10:36 AM

March 13, 2016

Michael Catanzaro: Do you trust this application?

Igalia WebKit

Much of the software you use is riddled with security vulnerabilities. Anyone who reads Matthew Garrett knows that most proprietary software is a lost cause. Some Linux advocates claim that free software is more secure than proprietary software, but it’s an open secret that tons of popular desktop Linux applications have many known, unfixed vulnerabilities. I rarely see anybody discuss this, as if it’s taboo, but it’s been obvious to me for a long time.

Usually vulnerabilities go unreported simply because nobody cares to look. Here’s an easy game: pick any application that makes HTTP connections — anything stuck on an old version of WebKit is a good place to start — and look for the following basic vulnerabilities:

  • Failure to use TLS when required (GNOME Music, GNOME Weather; note these are the only apps I mention here that do not use WebKit). This means the application has no security.
  • Failure to perform TLS certificate verification (Shotwell and Pantheon Photos). This means the application has no security against active attackers.
  • Failure to perform TLS certificate verification on subresources (Midori and XombreroLiferea). As sites usually send JavaScript in subresources, this means active attackers can get total control of the page by changing the script, without being detected (update: provided JavaScript is enabled). (Regrettably, Epiphany prior to 3.14.0 was also affected by this issue.)
  • Failure to perform TLS certificate verification before sending HTTP headers (private Midori bugBanshee). This leaks secure cookies, usually allowing attackers full access to your user account on a website. It also leaks the page you’re visiting, which HTTPS is supposed to keep private. (Update: Regrettably, Epiphany prior to 3.14.0 was affected by this issue. Also, the WebKit 2 API in WebKitGTK+ prior to 2.6.6, CVE-2015-2330.)

Except where noted, the latest release of all of the applications listed above are still vulnerable at the time of this writing, even though almost all of these bugs were reported long ago. With the exception of Shotwell, nobody has fixed any of these issues. Perhaps nobody working on the project cares to fix it, or perhaps nobody working on the project has the time or expertise to fix it, or perhaps nobody is working on the project anymore at all. This is all common in free software.

In the case of Shotwell, the issue has been fixed in git, but it might never be released because nobody works on Shotwell anymore. I informed distributors of the Shotwell vulnerability three months ago via the GNOME distributor list, our official mechanism for communicating with distributions, and advised them to update to a git snapshot. Most distributions ignored it. This is completely typical; to my knowledge, the stable releases of all Linux distributions except Fedora are still vulnerable.

If you want to play the above game, it should be very easy for you to add to my list by checking only popular desktop software. A good place to start would be to check if Liferea or Xombrero (supposedly a security-focused browser) perform TLS certificate verification before sending HTTP headers, or if Banshee performs verification on subresources, on the principle that vulnerable applications probably have other related vulnerabilities. (I did not bother to check.)

On a related note, many applications use insecure dependencies. Tons of popular GTK+ applications are stuck on an old, deprecated version of WebKitGTK+, for example. Many popular KDE applications use QtWebKit, which is old and deprecated. These deprecated versions of WebKit suffer from well over 100 remote code execution vulnerabilities fixed upstream that will probably never be backported. (100 is a lowball estimate; I would be unsurprised if the real number for QtWebKit was much, much higher.)

I do not claim that proprietary software is generally more secure than free software, because that is absolutely not true. Proprietary software vendors, including big name corporations that you might think would know better, are still churning out consumer products based on QtWebKit, for example. (This is unethical, but most proprietary software vendors do not care about security.) Not that it matters too much, as proprietary software vendors rarely provide comprehensive security updates anyway. (If your Android phone still gets updates, guess what: they’re superficial.) A few prominent proprietary software vendors really do care about security and do good work to keep their users safe, but they are rare exceptions, not the rule.

It’s a shame we’re not able to do better with free software.

By Michael Catanzaro at March 13, 2016 01:39 AM

March 12, 2016

Michael Catanzaro: Do you trust this website?

Igalia WebKit

TLS certificate validation errors are much less common on today’s Internet than they used to be, but you can still expect to run into them from time to time. Thanks to a decade of poor user interface decisions by web browsers (only very recently fixed in major browsers), users do not understand TLS and think it’s OK to bypass certificate warnings if they trust the site in question.

This is completely backwards. You should only bypass the warning if you do not trust the site.

The TLS certificate does not exist to state that the site is somehow trustworthy. It exists only to state that the site is the site you think it is: to ensure there is no man in the middle (MITM) attacker. If you are visiting https://www.example.com and get a certificate validation error, that means that even though your browser is displaying the URL https://www.example.com, there’s zero reason to believe you’re really visiting https://www.example.com rather than an attack site. Your browser can tell the difference, and it’s warning you. (More often, the site is just broken, or “misconfigured” if you want to be generous, but you and your browser have no way to know that.)

If you do not trust the site in question (e.g. you do not have any user account on the site), then there is not actually any harm in bypassing the warning. You don’t trust the site, so you do not care if a MITM is changing the page, recording your passwords, sending fake data to the site in your name, or whatever else.

But if you do trust the site, this error is cause to freak out and not continue, because it gives you have strong reason to believe there is a MITM attacker. Once you click continue, you should assume the MITM has total control over your interaction with the trusted website.

I will pick on Midori for an example of how bad design can confuse users:

The button label reads The button label reads “Trust this website,” but it should read “I do not trust this website.”

As you can see from the label, Midori has this very wrong. Users are misled into continuing if they trust the website: the very situation in which it is unsafe to continue.

Firefox and Chrome handle this much better nowadays, but not perfectly. Firefox says “Your connection is not secure” while Chrome says “Your connection is not private.” It would be better to say: “This doesn’t look like the real www.example.com.”

By Michael Catanzaro at March 12, 2016 10:55 PM

February 26, 2016

Xabier Rodríguez Calvar: Über latest Media Source Extensions improvements in WebKit with GStreamer

Igalia WebKit

In this post I am going to talk about the implementation of the Media Source Extensions (known as MSE) in the WebKit ports that use GStreamer. These ports are WebKitGTK+, WebKitEFL and WebKitForWayland, though only the latter has the latest work-in-progress implementation. Of course we hope to upstream WebKitForWayland soon and with it, this backend for MSE and the one for EME.

My colleague Enrique at Igalia wrote a post about this about a week ago. I recommend you read it before continuing with mine to understand the general picture and the some of the issues that I managed to fix on that implementation. Come on, go and read it, I’ll wait.

One of the challenges here is something a bit unnatural in the GStreamer world. We have to process the stream information and then make some metadata available to the JavaScript app before playing instead of just pushing everything to a playing pipeline and being happy. For this we created the AppendPipeline, which processes the data and extracts that information and keeps it under control for the playback later.

The idea of the our AppendPipeline is to put a data stream into it and get it processed at the other side. It has an appsrc, a demuxer (qtdemux currently

) and an appsink to pick up the processed data. Something tricky of the spec is that when you append data into the SourceBuffer, that operation has to block it and prevent with errors any other append operation while the current is ongoing, and when it finishes, signal it. Our main issue with this is that the the appends can contain any amount of data from headers and buffers to only headers or just partial headers. Basically, the information can be partial.

First I’ll present again Enrique’s AppendPipeline internal state diagram:

First let me explain the easiest case, which is headers and buffers being appended. As soon as the process is triggered, we move from Not started to Ongoing, then as the headers are processed we get the pads at the demuxer and begin to receive buffers, which makes us move to Sampling. Then we have to detect that the operation has ended and move to Last sample and then again to Not started. If we have received only headers we will not move to Sampling cause we will not receive any buffers but we still have to detect this situation and be able to move to Data starve and then again to Not started.

Our first approach was using two different timeouts, one to detect that we should move from Ongoing to Data starve if we did not receive any buffer and another to move from Sampling to Last sample if we stopped receiving buffers. This solution worked but it was a bit racy and we tried to find a less error prone solution.

We tried then to use custom downstream events injected from the source and at the moment they were received at the sink we could move from Sampling to Last sample or if only headers were injected, the pads were created and we could move from Ongoing to Data starve. It took some time and several iterations to fine tune this but we managed to solve almost all cases but one, which was receiving only partial headers and no buffers.

If the demuxer received partial headers and no buffers it stalled and we were not receiving any pads or any event at the output so we could not tell when the append operation had ended. Tim-Philipp gave me the idea of using the need-data signal on the source that would be fired when the demuxer ran out of useful data. I realized then that the events were not needed anymore and that we could handle all with that signal.

The need-signal is fired sometimes when the pipeline is linked and also when the the demuxer finishes processing data, regardless the stream contains partial headers, complete headers or headers and buffers. It works perfectly once we are able to disregard that first signal we receive sometimes. To solve that we just ensure that at least one buffer left the appsrc with a pad probe so if we receive the signal before any buffer was detected at the probe, it shall be disregarded to consider that the append has finished. Otherwise, if we have seen already a buffer at the probe we can consider already than any need-data signal means that the processing has ended and we can tell the JavaScript app that the append process has ended.

Both need-data signal and probe information come in GStreamer internal threads so we could use mutexes to overcome any race conditions. We thought though that deferring the operations to the main thread through the pipeline bus was a better idea that would create less issues with race conditions or deadlocks.

To finish I prefer to give some good news about performance. We use mainly the YouTube conformance tests to ensure our implementation works and I can proudly say that these changes reduced the time of execution in half!

That’s all folks!

By calvaris at February 26, 2016 12:30 PM

December 20, 2015

MathML at the Web Engines Hackfest 2015

Frédéric Wang

Hackfest

Two weeks ago, I travelled to Spain to participate to the second Web Engines Hackfest which was sponsored by Igalia and Collabora. Such an event has been organized by Igalia since 2009 and used to be focused on WebkitGTK+. It is great to see that it has now been extended to any Web engines & platforms and that a large percentage of non-igalian developers has been involved this year. If you did not get the opportunity to attend this event or if you are curious about what happened there, take a look at the wiki page or flickr album.

Last day of the hackfest
Photo from @webengineshackfest licensed under Creative Commons Attribution-ShareAlike

I really like this kind of hacking-oriented and participant-driven event where developers can meet face to face, organize themselves in small collaboration groups to efficiently make progress on a task or give passionate talk about what they have recently been working on. The only small bemol I have is that it is still mainly focused on WebKit/Blink developments. Probably, the lack of Mozilla/Microsoft participants is probably due to Mozilla Coincidental Work Weeks happening at the same period and to the proprietary nature of EdgeHTML (although this is changing?). However, I am confident that Igalia will try and address this issue and I am looking forward to coming back next year!

MathML developments

This year, Igalia developer Alejandro G. Castro wanted to work with me on WebKit's MathML layout code and more specifically on his MathML refactoring branch. Indeed, as many people (including Google developers) who have tried to work on WebKit's code in the past, he arrived to the conclusion that the WebKit's MathML layout code has many design issues that make it a burden for the rest of the layout team and too complex to allow future improvements. I was quite excited about the work he has done with Javier Fernández to try and move to a simple box model closer to what exists in Gecko and thus I actually extended my stay to work one whole week with them. We already submitted our proposal to the webkit-dev mailing list and received positive feedback, so we will now start merging what is ready. At the end of the week, we were quite satisfied about the new approach and confident it will facilitate future maintenance and developements :-)

Main room
Photo from @webengineshackfest licensed under Creative Commons Attribution-ShareAlike

While reading a recent thread on the Math WG mailing list, I realized that many MathML people have only vague understanding of why Google (or to be more accurate, the 3 or 4 engineers who really spent some time reviewing and testing the WebKit code) considered the implementation to be unsafe and not ready for release. Even worse, Michael Kholhase pointed out that for someone totally ignorant of the technical implementation details, the communication made some years ago around the "flexbox-based approach" gave the impression that it was "the right way" (indeed, it somewhat did improve the initial implementation) and the rationale to change that approach was not obvious. So let's just try and give a quick overview of the main problems, even if I doubt someone can have good understanding of the situation without diving into the C++ code:

  1. WebKit's code to stretch operator was not efficient at all and was limited to some basic fences buildable via Unicode characters.
  2. WebKit's MathML code violated many layout invariants, making the code unreliable.
  3. WebKit's MathML code relied heavily on the C++ renderer classes for flexboxes and has to manage too many anonymous renderers.

The main security concerns were addressed a long time ago by Martin Robinson and me. Glyph assembly for stretchy operators are now drawn using low-level font painting primitive instead of creating one renderer object for each piece and the preferred width for them no longer depends on vertical metrics (although we still need some work to obtain Gecko's good operator spacing). Also, during my crowdfunding project, I implemented partial support for the OpenType MATH table in WebKit and more specifically the MathVariant subtable, which allows to directly use construction of stretchy operators specified by the font designer and not only the few Unicode constructions.

However, the MathML layout code still modifies the renderer tree to force the presence of anonymous renderers and still applies specific CSS rules to them. It is also spending too much time trying to adapt the parent flexbox renderer class which has at the same time too much features for what is needed for MathML (essentially automatic box alignment) and not enough to get exact placement and measuring needed for high-quality rendering (the TeXBook rules are more complex, taking into account various parameters for box shifts, drops, gaps etc).

During the hackfest, we started to rewrite a clean implementation of some MathML renderer classes similar to Gecko's one and based on the MathML in HTML5 implementation note. The code now becomes very simple and understandable. It can be summarized into four main functions. For instance, to draw a fraction we need:

  • computePreferredLogicalWidths which sets the preferred width of the fraction during the first layout pass, by considering the widest between numerator and denominator.
  • layoutBlock and firstLineBaseline which calculate the final width/height/ascent of the fraction element and position the numerator and denominator.
  • paint which draws the fraction bar.

Perhaps, the best example to illustrate how the complexity has been reduced is the case of the renderer of mmultiscripts/msub/msup/msubsup elements (attaching an arbitrary number of subscripts and superscripts before or after a base). In the current WebKit implementation, we have to create three anonymous wrappers (a first one for the base, a second one for prescripts and a third one for postscripts) and an anonymous wrapper for each subscript/superscript pair, add alignment styles for these wrappers and spend a lot of time maintaining the integrity of the renderer tree when dynamic changes happen. With the new code, we just need to do arithmetic calculations to position the base and script boxes. This is somewhat more complex than the fraction example above but still, it remains arithmetic calculations and we can not reduce any further if we wish quality comparable to TeXBook / MATH rules. We actually take into account many parameters from the OpenType MATH table to get much better placement of scripts. We were able to fix bug 130325 in about twenty minutes instead of fighting with a CSS "negative margin" hack on anonymous renderers.

MathML dicussions

The first day of the hackfest we also had an interesting "breakout session" to define the tasks to work on during the hackfest. Alejandro briefly presented the status of his refactoring branch and his plan for the hackfest. As said in the previous section, we have been quite successful in following this plan: Although it is not fully complete yet, we expect to merge the current changes soon. Dominik Röttsches who works on Blink's font and layout modules was present at the MathML session and it was a good opportunity to discuss the future of MathML in Chrome. I gave him some references regarding the OpenType MATH table, math fonts and the MathML in HTML5 implementation note. Dominik said he will forward the references to his colleagues working on layout so that we can have deeper technical dicussion about MathML in Blink in the long term. Also, I mentioned noto-fonts issue 330, which will be important for math rendering in Android and actually does not depend on the MathML issue, so that's certainly something we could focus on in the short term.

Álex and Fred during the MathML breakout session
Photo from @webengineshackfest licensed under Creative Commons Attribution-ShareAlike

Alejandro also proposed to me to prepare a talk about MathML in Web Engines and exciting stuff happening with the MathML Association. I thus gave a brief overview of MathML and presented some demos of native support in Gecko. I also explained how we are trying to start a constructive approach to solve miscommunication between users, spec authors and implementers ; and gather technical and financial resources to obtain a proper solution. In a slightly more technical part, I presented Microsoft's OpenType MATH table and how it can be used for math rendering (and MathML in particular). Finally, I proposed my personal roadmap for MathML in Web engines. Although I do not believe I am a really great speaker, I received positive feedback from attendees. One of the thing I realized is that I do not know anything about the status and plan in EdgeHTML and so overlooked to mention it in my presentation. Its proprietary nature makes hard for external people to contribute to a MathML implementation and the fact that Microsoft is moving away from ActiveX de facto excludes third-party plugin for good and fast math rendering in the future. After I went back to Paris, I thus wrote to Microsoft employee Christian Heilmann (previously working for Mozilla), mentioning at least the MathML in HTML5 Implementation Note and its test suite as a starting point. MathML is currently on the first page of the most voted feature requested for Microsoft Edge and given the new direction taken with Microsoft Edge, I hope we could start a discussion on MathML in EdgeHTML...

Conclusion

This was a great hackfest and I'd like to thank again all the participants and sponsors for making it possible! As Alejandro wrote to me, "I think we have started a very interesting work regarding MathML and web engines in the future.". The short term plan is now to land the WebKit MathML refactoring started during the hackfest and to finish the work. I hope people now understand the importance of fonts with an OpenType MATH table for good mathematical rendering and we will continue to encourage browser vendors and font designers to make such fonts wide spread.

The new approach for WebKit MathML support gives good reason to be optmimistic in the long term and we hope we will be able to get high-quality rendering. The fact that the new approach addresses all the issues formulated by Google and that we started a dialogue on math rendering, gives several options for MathML in Blink. It remains to get Microsoft involved in implementing its own OpenType table in EdgeHTML. Overall, I believe that we can now have a very constructive discussion with the individuals/companies who really want native math support, with the Math WG members willing to have their specification implemented in browsers and with the browser vendors who want a math implementation which is good, clean and compatible with the rest of their code base. Hopefully, the MathML Association will be instrumental in achieving that. If everybody get involved, 2016 will definitely be an exciting year for native MathML in Web engines!

By fredw at December 20, 2015 05:15 PM

December 15, 2014

Web Engines Hackfest 2014

Gustavo Noronha

For the 6th year in a row, Igalia has organized a hackfest focused on web engines. The 5 years before this one were actually focused on the GTK+ port of WebKit, but the number of web engines that matter to us as Free Software developers and consultancies has grown, and so has the scope of the hackfest.

It was a very productive and exciting event. It has already been covered by Manuel RegoPhilippe Normand, Sebastian Dröge and Andy Wingo! I am sure more blog posts will pop up. We had Martin Robinson telling us about the new Servo engine that Mozilla has been developing as a proof of concept for both Rust as a language for building big, complex products and for doing layout in parallel. Andy gave us a very good summary of where JS engines are in terms of performance and features. We had talks about CSS grid layouts, TyGL – a GL-powered implementation of the 2D painting backend in WebKit, the new Wayland port, announced by Zan Dobersek, and a lot more.

With help from my colleague ChangSeok OH, I presented a description of how a team at Collabora led by Marco Barisione made the combination of WebKitGTK+ and GNOME’s web browser a pretty good experience for the Raspberry Pi. It took a not so small amount of both pragmatic limitations and hacks to get to a multi-tab browser that can play youtube videos and be quite responsive, but we were very happy with how well WebKitGTK+ worked as a base for that.

One of my main goals for the hackfest was to help drive features that were lingering in the bug tracker for WebKitGTK+. I picked up a patch that had gone through a number of iterations and rewrites: the HTML5 notifications support, and with help from Carlos Garcia, managed to finish it and land it at the last day of the hackfest! It provides new signals that can be used to authorize notifications, show and close them.

To make notifications work in the best case scenario, the only thing that the API user needs to do is handle the permission request, since we provide a default implementation for the show and close signals that uses libnotify if it is available when building WebKitGTK+. Originally our intention was to use GNotification for the default implementation of those signals in WebKitGTK+, but it turned out to be a pain to use for our purposes.

GNotification is tied to GApplication. This allows for some interesting features, like notifications being persistent and able to reactivate the application, but those make no sense in our current use case, although that may change once service workers become a thing. It can also be a bit problematic given we are a library and thus have no GApplication of our own. That was easily overcome by using the default GApplication of the process for notifications, though.

The show stopper for us using GNotification was the way GNOME Shell currently deals with notifications sent using this mechanism. It will look for a .desktop file named after the application ID used to initialize the GApplication instance and reject the notification if it cannot find that. Besides making this a pain to test – our test browser would need a .desktop file to be installed, that would not work for our main API user! The application ID used for all Web instances is org.gnome.Epiphany at the moment, and that is not the same as any of the desktop files used either by the main browser or by the web apps created with it.

For the future we will probably move Epiphany towards this new era, and all users of the WebKitGTK+ API as well, but the strictness of GNOME Shell would hurt the usefulness of our default implementation right now, so we decided to stick to libnotify for the time being.

Other than that, I managed to review a bunch of patches during the hackfest, and took part in many interesting discussions regarding the next steps for GNOME Web and the GTK+ and Wayland ports of WebKit, such as the potential introduction of a threaded compositor, which is pretty exciting. We also tried to have Bastien Nocera as a guest participant for one of our sessions, but it turns out that requires more than a notebook on top of a bench hooked up to   a TV to work well. We could think of something next time ;D.

I’d like to thank Igalia for organizing and sponsoring the event, Collabora for sponsoring and sending ChangSeok and myself over to Spain from far away Brazil and South Korea, and Adobe for also sponsoring the event! Hope to see you all next year!

Web Engines Hackfest 2014 sponsors: Adobe, Collabora and Igalia

Web Engines Hackfest 2014 sponsors: Adobe, Collabora and Igalia

By kov at December 15, 2014 11:20 PM

December 08, 2014

How to build TyGL

University of Szeged

This is a follow-up blog post of our announcement of TyGL - the 2D-accelerated GPU rendering port of WebKit.

We have been received lots of feedback about TyGL and we would like to thank you for all questions, suggestions and comments. As we promised lets get into some technical details.

read more

By szilard.ledan at December 08, 2014 12:47 PM

November 12, 2014

Announcing the TyGL-WebKit port to accelerate 2D web rendering with GPU

University of Szeged

We are proud to announce the TyGL port (link: http://github.com/szeged/TyGL) on the top of EFL-WebKit. TyGL (pronounced as tigel) is part of WebKit and provides 2D-accelerated GPU rendering on embedded systems. The engine is purely GPU based. It has been developed on and tested against ARM-Mali GPU, but it is designed to work on any GPU conforming to OpenGL ES 2.0 or higher.

The GPU involvement on future graphics is inevitable considering the pixel growth rate of displays, but harnessing the GPU power requires a different approach than CPU-based optimizations.

read more

By zoltan.herczeg at November 12, 2014 02:18 PM

October 22, 2014

Fuzzinator reloaded

University of Szeged

It's been a while since I last (and actually first) posted about Fuzzinator. Now I think that I have enough new experiences worth sharing.

More than a year ago, when I started fuzzing, I was mostly focusing on mutation-based fuzzer technologies since they were easy to build and pretty effective. Having a nice error-prone test suite (e.g. LayoutTests) was the warrant for fresh new bugs. At least for a while.

read more

By renata.hodovan at October 22, 2014 10:38 PM

September 25, 2014

Measuring ASM.JS performance

University of Szeged

What is ASM.JS?

Now that mobile computers and cloud services become part of our lives, more and more developers see the potential of the web and online applications. ASM.JS, a strict subset of JavaScript, is a technology that provides a way to achieve near native speed in browsers, without the need of any plugin or extension. It is also possible to cross-compile C/C++ programs to it and running them directly in your browser.

In this post we will compare the JavaScript and ASM.JS performance in different browsers, trying out various kinds of web applications and benchmarks.

read more

By matyas.mustoha at September 25, 2014 10:40 AM

August 28, 2014

CSS Shapes now available in Chrome 37 release

Adobe Web Platform

Support for CSS Shapes is now available in the latest Google Chrome 37 release.

chromelogo

What can I do with CSS Shapes?

CSS Shapes lets you think out of the box! It gives you the ability to wrap content outside any shape. Shapes can be defined by geometric shapes, images, and even gradients. Using Shapes as part of your website design takes a visitor’s visual and reading experience to the next level. If you want to start with some tutorials, please go visit Sarah Soueidan’s article about Shapes.

Demo

The following shapes use case is from the Good Looking Shapes Gallery blog post.

Without CSS Shapes
the_11_guesses_no_shapes
With CSS Shapes
the_11_guesses_shapes

In the first picture, we don’t use CSS Shapes. The text wraps around the rectangular image container, which leads to a lot of empty space between the text and the visible part of the image.

In the second picture, we use CSS Shapes. You can see the wrapping behavior around the image. In this case the white parts of the image are transparent, thus the browser can automatically wrap the content around the visible part, which leads to this nice and clean, visually more appealing wrapping behavior.

How do I get CSS Shapes?

Just update your Chrome browser to the latest version from the Chrome/About Google Chrome menu, or download the latest stable version from https://www.google.com/chrome/browser/.

I’d like to thank the collaboration of WebKit and Blink engineers, and everyone else in the community who has contributed to this feature. The fact that Shapes is shipping in two production browsers — Chrome 37 now and Safari 8 later this year — is the upshot of the open source collaboration between the people who believe in a better, more expressive web. Although Shapes will be available in these browsers, you’ll need another solution for the other browsers. The CSS Shapes Polyfill is one method of achieving consistent behavior across browsers.

Where should I start?

For more info about CSS Shapes, please check out the following links:

Let us know your thoughts or if you have nice demos, here or on Twitter: @AdobeWeb and @ZoltanWebKit.

By Zoltan Horvath at August 28, 2014 05:12 PM

May 13, 2014

Good-Looking Shapes Gallery

Adobe Web Platform

As a modern consumer of media, you rarely crack open a magazine or a pamphlet or anything that would be characterized as “printed”. Let me suggest that you take a walk on the wild side. The next time you are in a doctor’s office, or a supermarket checkout lane, or a library, thumb though a magazine. Most of the layouts you’ll find inside can also be found on the web, but not all of them. Layouts where content hugs the boundaries of illustrations are common in print and rare on the web. One of the reasons non-rectangular contour-hugging layouts are uncommon on the web is that they are difficult to produce.

They are not difficult to produce anymore.

The CSS Shapes specification is now in the final stages of standardization. This feature enables flowing content around geometric shapes (like circles and polygons), as well as around shapes defined by an image’s alpha channel. Shapes make it easy to produce the kinds of layouts you can find in print today, with all the added flexibility and power that modern online media affords. You can use CSS Shapes right now with the latest builds of WebKit and Blink based browsers, like Safari and Chrome.

Development of CSS Shapes has been underway for about two years, and we’ve been regularly heralding its progress here. Many of those reports have focused on the evolution of the spec and implementations, and they’ve included examples that emphasized basics over beauty. This article is an attempt to tilt the balance back towards good-looking. Listed below are simple shapes demos that we think look pretty good. Everyone on Adobe’s CSS Shapes engineering team contributed at least one.

There’s a live CodePen.io version of each demo in the gallery. Click on the demo screenshot or one of the handy links to take a look. You’ll want to view the demos with a browser that supports Shapes and you’ll need to enable CSS Shapes in that browser. For example you can use a nightly build of the Safari browser or you can enable shapes in Chrome or Chrome Canary like this:

  1. Copy and paste chrome://flags/#enable-experimental-web-platform-features into the address bar, then press enter.
  2. Click the ‘Enable’ link within that section.
  3. Click the ‘Relaunch Now’ button at the bottom of the browser window.

A few of the demos use the new Shapes Polyfill and will work in most browsers.

And now, without further ado, please have a look through our good-looking shapes gallery.


Ozma of Oz

ozma-demo-screenshot

This demo reproduces the layout style that opens many of the chapters of the L. Frank Baum books, including Ozma of Oz.  The first page is often dominated by an illustration on the left or right. The chapter’s text conforms to the illustration, but not too tightly. The books were published over 100 years ago and they still look good print.  With CSS Shapes they can still look good on the web.

Top Cap

topcap-demo-screenshot

The conventional “drop-cap” opens a paragraph by enlarging and highlighting the first letter, word or phrase. The drop-cap’s goal is to draw your attention to where you can start reading. This demo delivers the same effect by crowning the entire opening paragraph with a “top cap” that funnels your attention into the article. In both cases, what’s going on is a segue from a graphic element to the text.

Violator

monsters-demo-screenshot

A violator is small element that “violates” rectangular text layout by encroaching on a corner or a small part of an edge. This layout idiom is common in short-form magazines and product packaging. That “new and improved” banner which blazes through the corner of thousands of consumer products (whether or not they are new or improved) – it’s a violator.

Column Interest

columns-demo-screenshot

When a print magazine feels the need to incorporate some column layout melodrama, they often reach for this idiom. The shape spans a pair of columns, which creates visual interest in the middle of the page. Without it you’d be faced with a wall of attention sapping text and more than likely turn the page.

Caption

Screenshot of the wine jug caption demo.

The old-school approach for including a caption with an image is to put the caption text alongside or below the image. Putting a caption on top of an image requires a little more finesse, since you have to ensure that the text doesn’t obscure anything important and that the text is rendered in a way that preserves readability.  The result can be relatively attractive.

This photograph was taken by Zoltan Horvath who has pointed out that I’ve combined a quote about tea with a picture of a ceremonial wine jug.  I apologize for briefly breaching that beverage boundary. It’s just a demo.

Paging

Screenshot of the paging demo.

With a layout like this, one could simple let the content wrap and around the shape on the right and then expand into the usual rectangle.  In this demo the content is served up a paragraph at a time, in response to the left and right arrow keys.

Note also: yes in fact the mate gourd is perched on exactly the same windowsill as the previous demo. Zoltan and Pope Francis are among the many fans of yerba mate tea.

Ersatz shape-inside

Screenshot of the ersatz shape-inside demo.

Originally the CSS Shapes spec included shape-inside as well as shape-outside. Sadly, shape-inside was promoted to “Level 2″ of the spec and isn’t available in the current implementations. Fortunately for shape insiders everywhere, it’s still sometimes possible to mimic shape-inside with an adjacent pair of carefully designed shape-outside floats. This demo is a nice example of that, where the text appears inside a bowl of oatmeal.

Animation

animation-demo-screeenshot

This is an animated demo, so to appreciate it you’ll really need to take a look at the live version. It is an example of using an animated shape to draw the user’s attention to a particular message.  Of course one must use this approach with restraint, since an animated loop on a web page doesn’t just gently tug at the user’s attention. It drags at their attention like a tractor beam.

Performance

performance-demo-screenshot

Advertisements are intended to grab the user’s attention and a second or two of animation will do that. In this demo a series of transition motions have been strung together into a tiny performance that will temporarily get the reader’s attention. The highlight of the performance is – of course – the text snapping into the robot’s contour for the finale. Try and imagine a soundtrack that punctuates the action with some whirring and clanking noises, it’s even better that way.

By hmuller at May 13, 2014 05:38 PM

April 24, 2014

Adobe Web Platform Goes to the 2014 WebKit Contributors’ Meeting

Adobe Web Platform

Last week, Apple hosted the 2014 WebKit Contributors’ Meeting at their campus in Cupertino. As usual it was an unconference-style event, with session scheduling happening on the morning of the first day. While much of the session content was very specific to WebKit implementation, there were topics covered that are interesting to the wider web community. This post is a roundup of some of these topics from the sessions that Adobe Web Platform Team members attended.

CSS Custom Properties for Cascading Variables

Alan Stearns suggested a session on planning a new implementation of CSS Custom Properties for Cascading Variables. While implementations of this spec have been attempted in WebKit in the past, they never got past the experimental stage. Despite this, there is still much interest in implementing this feature. In addition, the current version of the spec has addressed many of the issues that WebKit contributors had previously expressed. We talked about a possible issue with using variables in custom property values, which Alan is investigating. More detail is available in the notes from the Custom Properties session.

CSS Regions

Andrei Bucur presented the current state of the CSS Regions implementation in WebKit. The presentation was well received and well attended. Notably, this was one of the few sessions with enough interest that it had a time slot all to itself.

While CSS Regions shipped last year in iOS 7 and Safari 6.1 and 7, the implementation in WebKit hasn’t been standing still. Andrei mentioned the following short list of changes in WebKit since the last Safari release:

  • correct painting of fragments and overflow
  • scrollable regions
  • accelerated content inside regions
  • position: fixed elements
  • the regionoversetchange event
  • better selection
  • better WebInspector integration
  • and more…

Andrei’s slides outlining the state of CSS Regions also contain a roadmap for the feature’s future in WebKit as well as a nice demo of the fix to fragment and overflow handling. If you are following the progress of CSS Regions in WebKit, the slides are definitely worth a look. (As of this writing, the Regions demo in the slides only works in Safari and WebKit Nightly.)

CSS Shapes

Zoltan Horvath, Bear Travis, and I covered the current state of CSS Shapes in WebKit. We are almost done implementing the functionality in Level 1 of the CSS Shapes Specification (which is itself a Candidate Recommendation, the last step before becoming an official W3C standard). The discussion in this session was very positive. We received good feedback on use cases for shape-outside and even talked a bit about the possibilities for when shape-inside is revisited as part of CSS Shapes Level 2. While I don’t have any slides or demos to share at the moment, we will soon be publishing a blog post to bring everyone up to date on the latest in CSS Shapes. So watch this space for more!

Subpixel Layout

This session was mostly about implementation. However, Zalan Bujtas drew an interesting distinction between subpixel layout and subpixel painting. Subpixel layout allows for better space utilization when laying out elements on the page, as boxes can be sized and positioned more precisely using fractional units. Subpixel painting allows for better utilization of high DPI displays by actually drawing elements on the screen using fractional CSS pixels (For example: on a 2x “Retina” display, half of a CSS pixel is one device pixel). Subpixel painting allows for much cleaner lines and smoother animations on high DPI displays when combined with subpixel layout. While subpixel layout is currently implemented in WebKit, subpixel painting is currently a work in progress.

Web Inspector

The Web Inspector is full of shiny new features. The front-end continues to shift to a new design, while the back-end gets cleaned up to remove cruft. The architecture for custom visual property editors is in place and will hopefully enable quick and intuitive editing of gradients, transforms, and animations in the future. Other goodies include new breakpoint actions (like value logging), a redesigned timeline, and IndexedDB debugging support. The Web Inspector still has room for new features, and you can always check out the #webkit-inspector channel on freenode IRC for the latest and greatest.

Web Components

The Web Components set of features continues to gather interest from the browser community. Web Components is made up of four different features: HTML Components, HTML Imports, Shadow DOM, and HTML Templates. The general gist of the talk was that the Web Components concepts are desirable, but there are concerns that the features’ complexity may make implementation difficult. The main concerns seemed to center around performance and encapsulation with Shadow DOM, and will hopefully be addressed with a prototype implementation of the feature (in the works). You can also take a look at the slides from the Web Components session.

CSS Grid Layout

The WebKit implementation of the CSS Grid Layout specification is relatively advanced. After learning in this session that the only way to test out Grid Layout in WebKit was to make a custom build with it enabled, session attendees concluded that it should be turned on by default in the WebKit Nightlies. So in the near future, experimenting with Grid Layout in WebKit should be as easy as installing a nightly build.

More?

As I mentioned earlier, this was just a high-level overview of a few of the topics at this year’s WebKit Contributors’ Meeting. Notes and slides for some of the topics not mentioned here are available on the 2014 WebKit Meeting page in the wiki. The WebKit project is always welcoming new contributors, so if you happen to see a topic on that wiki page that interests you, feel free to get in touch with the community and see how you can get involved.

Acknowledgements

This post would not have been possible without the notes and editing assistance of my colleagues on the Adobe Web Platform Team that attended the meeting along with me: Alan Stearns, Andrei Bucur, Bear Travis, and Zoltan Horvath.

By Bem Jones-Bey at April 24, 2014 05:23 PM

March 18, 2014

QtWebKit is no more, what now?

Gustavo Noronha

Driven by the technical choices of some of our early clients, QtWebKit was one of the first web engines Collabora worked on, building the initial support for NPAPI plugins and more. Since then we had kept in touch with the project from time to time when helping clients with specific issues, hardware or software integration, and particularly GStreamer-related work.

With Google forking Blink off WebKit, a decision had to be made by all vendors of browsers and platform APIs based on WebKit on whether to stay or follow Google instead. After quite a bit of consideration and prototyping, the Qt team decided to take the second option and build the QtWebEngine library to replace QtWebKit.

The main advantage of WebKit over Blink for engine vendors is the ability to implement custom platform support. That meant QtWebKit was able to use Qt graphics and networking APIs and other Qt technologies for all of the platform-integration needs. It also enjoyed the great flexibility of using GStreamer to implement HTML5 media. GStreamer brings hardware-acceleration capabilities, support for several media formats and the ability to expand that support without having to change the engine itself.

People who are using QtWebKit because of its being Gstreamer-powered will probably be better served by switching to one of the remaining GStreamer-based ports, such as WebKitGTK+. Those who don’t care about the underlying technologies but really need or want to use Qt APIs will be better served by porting to the new QtWebEngine.

It’s important to note though that QtWebEngine drops support for Android and iOS as well as several features that allowed tight integration with the Qt platform, such as DOM manipulation through the QWebElement APIs, making QObject instances available to web applications, and the ability to set the QNetworkAccessManager used for downloading resources, which allowed for fine-grained control of the requests and sharing of cookies and cache.

It might also make sense to go Chromium/Blink, either by using the Chrome Content API, or switching to one its siblings (QtWebEngine included) if the goal is to make a browser which needs no integration with existing toolkits or environments. You will be limited to the formats supported by Chrome and the hardware platforms targeted by Google. Blink does not allow multiple implementations of the platform support layer, so you are stuck with what upstream decides to ship, or with a fork to maintain.

It is a good alternative when Android itself is the main target. That is the technology used to build its main browser. The main advantage here is you get to follow Chrome’s fast-paced development and great support for the targeted hardware out of the box. If you need to support custom hardware or to be flexible on the kinds of media you would like to support, then WebKit still makes more sense in the long run, since that support can be maintained upstream.

At Collabora we’ve dealt with several WebKit ports over the years, and still actively maintain the custom WebKit Clutter port out of tree for clients. We have also done quite a bit of work on Chromium-powered projects. Some of the decisions you have to make are not easy and we believe we can help. Not sure what to do next? If you have that on your plate, get in touch!

By kov at March 18, 2014 07:44 PM

February 25, 2014

Improving your site’s visual details: CSS3 text-align-last

Adobe Web Platform

In this post, I want to give a status report regarding the text-align-last CSS3 property. If you are interested in taking control of the small visual details of your site with CSS, I encourage you to keep reading.

The problem

First, let’s talk about why we need this property. You’ve probably already seen many text blocks on pages that don’t quite seem visually correct, because the last line isn’t justified with the previous lines. Check out the example paragraph below:

Example of the CSS3 text-align-last property

In the first column, the last line isn’t justified. This is the expected behavior, when you apply the ‘text-align: justify’ CSS property on a container. On the other hand, in the second column, the content is entirely justified, including the last line.

The solution

This magic is the ‘text-align-last’ CSS3 property, which is set to justify on the second container. The text-align-last property is part of the CSS Text Module Level 3 specification, which is currently a working draft. The text-align-last property describes how the last line of a block or a line right before a forced line break is aligned when ‘text-align’ is ‘justify’, which means you gain full control over the alignment of the last line of a block. The property allows several more options, which you can read about on WebPlatform.org docs, or the CSS Text Module Level 3 W3C Specification.

A possible use case (Added April – 2014)

After looking at the previous example (which was rather focusing on the functionality of the property), let’s move on to a more realistic use case. The feature is perfect to make our multi-line captions look better. Check out the centered, and the justified image caption examples below.

centertext_align__simple_justify

And now, compare them with a justified, multi-line caption, where the last line has been centered by text-align-last: center.
text_align_last_center

I think the proper alignment of the last line gives a better overlook to the caption.

Browser Support

I recently added rendering support for the property in WebKit (Safari) based on the latest specification. Dongwoo Joshua Im from Samsung added rendering support in Blink (Chrome). If you like to try it out in WebKit, you’ll need to make a custom developer build and use the CSS3 text support build flag (--css3-text).

The property is already included in Blink’s developer nightlies by default, so after launching your latest Chrome Canary, you only need to enable ‘Enable experimental Web Platform features’ under chrome://flags, and enjoy the full control over your last lines.

Developer note

Please keep in mind that both the W3C specification and the implementations are under experimental status. I’ll keep blogging about the feature and let you know if anything changes, including when the feature ships for production use!

By Zoltan Horvath at February 25, 2014 04:58 PM

January 05, 2014

Funding MathML Developments in Gecko and WebKit (part 2)

Frédéric Wang

As I mentioned three months ago, I wanted to start a crowdfunding campaign so that I can have more time to devote to MathML developments in browsers and (at least for Mozilla) continue to mentor volunteer contributors. Rather than doing several crowdfunding campaigns for small features, I finally decided to do a single crowdfunding campaign with Ulule so that I only have to worry only once about the funding. This also sounded more convenient for me to rely on some French/EU website regarding legal issues, taxes etc. Also, just like Kickstarter it's possible with Ulule to offer some "rewards" to backers according to the level of contributions, so that gives a better way to motivate them.

As everybody following MathML activities noticed, big companies/organizations do not want to significantly invest in funding MathML developments at the moment. So the rationale for a crowdfunding campaign is to rely on the support of the current community and on the help of smaller companies/organizations that have business interest in it. Each one can give a small contribution and these contributions sum up in enough money to fund the project. Of course this model is probably not viable for a long term perspective, but at least this allows to start something instead of complaining without acting ; and to show bigger actors that there is a demand for these developments. As indicated on the Ulule Website, this is a way to start some relationship and to build a community around a common project. My hope is that it could lead to a long term funding of MathML developments and better partnership between the various actors.

Because one of the main demand for MathML (besides accessibility) is in EPUB, I've included in the project goals a collection of documents that demonstrate advanced Web features with native MathML. That way I can offer more concrete rewards to people and federate them around the project. Indeed, many of the work needed to improve the MathML rendering requires some preliminary "code refactoring" which is not really exciting or immediately visible to users...

Hence I launched the crowdfunding campaign the 19th of November and we reached 1/3 of the minimal funding goal in only three days! This was mainly thanks to the support of individuals from the MathML community. In mid december we reached the minimal funding goal after a significant contribution from the KWARC Group (Jacobs University Bremen, Germany) with which I have been in communication since the launch of the campaign. Currently, we are at 125% and this means that, minus the Ulule commision and my social/fiscal obligations, I will be able to work on the project during about 3 months.

I'd like to thank again all the companies, organizations and people who have supported the project so far! The crowdfunding campaign continues until the end of January so I hope more people will get involved. If you want better MathML in Web rendering engines and ebooks then please support this project, even a symbolic contribution. If you want to do a more significant contribution as a company/organization then note that Ulule is only providing a service to organize the crowdfunding campaign but otherwise the funding is legally treated the same as required by my self-employed status; feel free to contact me for any questions on the project or funding and discuss the long term perspective.

Finally, note that I've used my savings and I plan to continue like that until the official project launch in February. Below is a summary of what have been done during the five weeks before the holiday season. This is based on my weekly updates for supporters where you can also find references to the Bugzilla entries. Thanks to the Apple & Mozilla developers who spent time to review my patches!

Collection of documents

The goal is to show how to use existing tools (LaTeXML, itex2MML, tex4ht etc) to build EPUB books for science and education using Web standards. The idea is to cover various domains (maths, physics, chemistry, education, engineering...) as well as Web features. Given that many scientific circles are too much biased by "math on paper / PDF" and closed research practices, it may look innovative to use the Open Web but to be honest the MathML language and its integration with other Web formats is well established for a long time. Hence in theory it should "just work" once you have native MathML support, without any circonvolutions or hacks. Here are a couple of features that are tested in the sample EPUB books that I wrote:

  • Rendering of MathML equations (of course!). Since the screen size and resolution vary for e-readers, automatic line breaking / reflowing of the page is "naturally" tested and is an important distinction with respect to paper / PDF documents.
  • CSS styling of the page and equations. This includes using (Web) fonts, which are very important for mathematical publishing.
  • Using SVG schemas and how they can be mixed with MathML equations.
  • Using non-ASCII (Arabic) characters and RTL/LTR rendering of both the text and equations.
  • Interactive document using Javascript and <maction>, <input>, <button> etc. For those who are curious, I've created some videos for an algebra course and a lab practical.
  • Using the <video> element to include short sequences of an experiment in a physics course.
  • Using the <canvas> element to draw graphs of functions or of physical measurements.
  • Using WebGL to draw interactive 3D schemas. At the moment, I've only adapted a chemistry course and used ChemDoodle to load Crystallographic Information Files (CIF) and provide 3D-representation of crystal structures. But of course, there is not any problem to put MathML equations in WebGL to create other kinds of scientific 3D schemas.

WebKit

I've finished some work started as a MathJax developer, including the maction support requested by the KWARC Group. I then tried to focus on the main goals: rendering of token elements and more specifically operators (spacing and stretching).

  • I improved LTR/RTL handling of equations (full RTL support is not implemented yet and not part of the project goal).
  • I improved the maction elements and implemented the toggle actiontype.
  • I refactored the code of some "mrow-like" elements to make them all behave like an <mrow> element. For example while WebKit stretched (some) operators in <mrow> elements it could not stretch them in <mstyle>, <merror> etc Similarly, this will be needed to implement correct spacing around operators in <mrow> and other "mrow-like" elements.
  • I analyzed more carefully the vertical stretching of operators. I see at least two serious bugs to fix: baseline alignment and stretch size. I've uploaded an experimental patch to improve that.
  • Preliminary work on the MathML Operator Dictionary. This dictionary contains various properties of operators like spacing and stretchiness and is fundamental for later work on operators.
  • I have started to refactor the code for mi, mo and mfenced elements. This is also necessary for many serious bugs like the operator dictionary and the style of mi elements.
  • I have written a patch to restore support for foreign objects in annotation-xml elements and to implement the same selection algorithm as Gecko.

Gecko

I've continued to clean up the MathML code and to mentor volunteer contributors. The main goal is the support for the Open Type MATH table, at least for operator stretching.

  • Xuan Hu's work on the <mpadded> element landed in trunk. This element is used to modify the spacing of equations, for example by some TeX-to-MathML generators.
  • On Linux, I fixed a bug with preferred widths of MathML token elements. Concretely, when equations are used inside table cells or similar containers there is a bug that makes equations overflow the containers. Unfortunately, this bug is still present on Mac and Windows...
  • James Kitchener implemented the mathvariant attribute (e.g used by some tools to write symbols like double-struck, fraktur etc). This also fixed remaining issues with preferred widths of MathML token elements. Khaled Hosny started to update his Amiri and XITS fonts to add the glyphs for Arabic mathvariants.
  • I finished Quentin Headen's code refactoring of mtable. This allowed to fix some bugs like bad alignment with columnalign. This is also a preparation for future support for rowspacing and columnspacing.
  • After the two previous points, it was finally possible to remove the private "_moz-" attributes. These were visible in the DOM or when manipulating MathML via Javascript (e.g. in editors, tree inspector, the html5lib etc)
  • Khaled Hosny fixed a regression with script alignments. He started to work on improvements regarding italic correction when positioning scripts. Also, James Kitchener made some progress on script size correction via the Open Type "ssty" feature.
  • I've refactored the stretchy operator code and prepared some patches to read the OpenType MATH table. You can try experimental support for new math fonts with e.g. Bill Gianopoulos' builds and the MathML Torture Tests.

Blink/Trident

MathML developments in Chrome or Internet Explorer is not part of the project goal, even if obviously MathML improvements to WebKit could hopefully be imported to Blink in the future. Users keep asking for MathML in IE and I hope that a solution will be found to save MathPlayer's work. In the meantime, I've sent a proposal to Google and Microsoft to implement fallback content (alttext and semantics annotation) so that authors can use it. This is just a couple of CSS rules that could be integrated in the user agent style sheet. Let's see which of the two companies is the most reactive...

By fredw at January 05, 2014 07:45 PM

December 11, 2013

WebKitGTK+ hackfest 5.0 (2013)!

Gustavo Noronha

For the fifth year in a row the fearless WebKitGTK+ hackers have gathered in A Coruña to bring GNOME and the web closer. Igalia has organized and hosted it as usual, welcoming a record 30 people to its office. The GNOME foundation has sponsored my trip allowing me to fly the cool 18 seats propeller airplane from Lisbon to A Coruña, which is a nice adventure, and have pulpo a feira for dinner, which I simply love! That in addition to enjoying the company of so many great hackers.

Web with wider tabs and the new prefs dialog

Web with wider tabs and the new prefs dialog

The goals for the hackfest have been ambitious, as usual, but we made good headway on them. Web the browser (AKA Epiphany) has seen a ton of little improvements, with Carlos splitting the shell search provider to a separate binary, which allowed us to remove some hacks from the session management code from the browser. It also makes testing changes to Web more convenient again. Jon McCan has been pounding at Web’s UI making it more sleek, with tabs that expand to make better use of available horizontal space in the tab bar, new dialogs for preferences, cookies and password handling. I have made my tiny contribution by making it not keep tabs that were created just for what turned out to be a download around. For this last day of hackfest I plan to also fix an issue with text encoding detection and help track down a hang that happens upon page load.

Martin Robinson and Dan Winship hack

Martin Robinson and Dan Winship hack

Martin Robinson and myself have as usual dived into the more disgusting and wide-reaching maintainership tasks that we have lots of trouble pushing forward on our day-to-day lives. Porting our build system to CMake has been one of these long-term goals, not because we love CMake (we don’t) or because we hate autotools (we do), but because it should make people’s lives easier when adding new files to the build, and should also make our build less hacky and quicker – it is sad to see how slow our build can be when compared to something like Chromium, and we think a big part of the problem lies on how complex and dumb autotools and make can be. We have picked up a few of our old branches, brought them up-to-date and landed, which now lets us build the main WebKit2GTK+ library through cmake in trunk. This is an important first step, but there’s plenty to do.

Hackers take advantage of the icecream network for faster builds

Hackers take advantage of the icecream network for faster builds

Under the hood, Dan Winship has been pushing HTTP2 support for libsoup forward, with a dead-tree version of the spec by his side. He is refactoring libsoup internals to accomodate the new code paths. Still on the HTTP front, I have been updating soup’s MIME type sniffing support to match the newest living specification, which includes specification for several new types and a new security feature introduced by Internet Explorer and later adopted by other browsers. The huge task of preparing the ground for a one process per tab (or other kinds of process separation, this will still be topic for discussion for a while) has been pushed forward by several hackers, with Carlos Garcia and Andy Wingo leading the charge.

Jon and Guillaume battling code

Jon and Guillaume battling code

Other than that I have been putting in some more work on improving the integration of the new Web Inspector with WebKitGTK+. Carlos has reviewed the patch to allow attaching the inspector to the right side of the window, but we have decided to split it in two, one providing the functionality and one the API that will allow browsers to customize how that is done. There’s a lot of work to be done here, I plan to land at least this first patch durign the hackfest. I have also fought one more battle in the never-ending User-Agent sniffing war, in which we cannot win, it looks like.

Hackers chillin' at A Coruña

Hackers chillin’ at A Coruña

I am very happy to be here for the fifth year in a row, and I hope we will be meeting here for many more years to come! Thanks a lot to Igalia for sponsoring and hosting the hackfest, and to the GNOME foundation for making it possible for me to attend! See you in 2014!


By kov at December 11, 2013 09:47 AM

October 15, 2013

Funding MathML Developments in Gecko and WebKit

Frédéric Wang

update 2013-10-15: since I got feedback, I have to say that my funding plan is independent of my work at MathJax ; I'm not a MathJax employee but I have an independent contractor status. Actually, I already used my business to fund an intern for Gecko MathML developments during Summer 2011 :-)

Retrospect

Since last April, I have been allowed by the MathJax Consortium to dedicate a small amount of my time to do MathML development in browsers, until possibly more serious involvement later. At the same time, we mentioned this plan to Google developers but unfortunately they just decided to drop the WebKit MathML code from Blink, making external contributions hard and unwelcome...

Hence I have focused mainly on Gecko and WebKit: You can find the MathML bugs that have been closed during that period on bugzilla.mozilla.org and bugs.webkit.org. For Gecko, this has allowed me to finish some of the work I started as a volunteer before I was involved full-time in MathJax as well as to continue to mentor MathML contributors. Regarding WebKit, I added a few new basic features like MathML lengths, <mspace> or <mmultiscripts> while I was getting familiar with the MathML code and WebKit organization/community. I also started to work on <semantics> and <maction>. More importantly, I worked with Martin Robinson to address the design concerns of Google developers and a patch to fix these issues finally landed early this week.

However, my progress has been slow so as I mentioned in my previous blog post, I am planning to find a way to fund MathML developments...

Why funding MathML?

Note: I am assuming that the readers of this blog know why MathML is important and are aware of the benefits it can bring to the Web community. If not, please check Peter Krautzberger's Interview by Fidus Writer or the MozSummit MathML slides for a quick introduction. Here my point is to explain why we need more than volunteer-driven development for MathML.

First the obvious thing: Volunteer time is limited so if we really want to see serious progress in MathML support we need to give a boost to MathML developments. e-book publishers/readers, researchers/educators who are stuck outside the Web in a LaTeX-to-PDF world, developers/users of accessibility tools or the MathML community in general want good math support in browsers now and not to wait again for 15 more years until all layout engines catch up with Gecko or that the old Gecko bugs are fixed.

MathML

There are classical misunderstandings from people thinking that non-native MathML solutions and other polyfills are the future or that math on the Web could be implemented via PNG/SVG images or Web Components. Just open a math book and you will see that e.g. inline equations must be correctly aligned with the text or participate in line wrapping. Moreover we are considering math on the Web not math on paper, so we want it to be compatible with HTML, SVG, CSS, Javascript, Unicode, Bidi etc and also something that is fast and responsive. Technically, this means that a clean solution must be in the core rendering engine, spread over several parts of the code and must have strong interaction with the various components like the HTML5 parser, the layout tree, the graphic and font libraries, the DOM module, the style tree and so forth. I do not see any volunteer-driven Blink/Gecko/WebKit feature off the top of my head that has this characteristic and actually even SVG or any other kind of language for graphics have less interaction with HTML than MathML has.

The consequence of this is that it is extremely difficult for volunteers to get involved in native MathML and to do quick progress because they have to understand how the various components of the Blink/Gecko/WebKit code work and be sure to do things correctly. Good mathematical rendering is already something hard by itself, so that is even more complicated when you are not writing an isolated rendering engine for math on which you can have full control. Also, working at the Blink/Gecko/WebKit level requires technical skills above the average so finding volunteers who can work with the high-minded engineers of the big browser companies is not something easy. For instance, among the enthusiastic people coming to me and willing to help MathML in Gecko, many got stuck when e.g. they tried to build the Firefox source or do something more advanced and I never heard back from them. In the other direction, Blink/Gecko/WebKit paid developers are generally not familiar with MathML and do not have time to learn more about it and thus can not always provide a relevant review of the code, or they may break something while trying to modify code they do not entirely understand. Moreover, both the volunteers and paid staff have only a small amount of time to do MathML stuff while the other parts of the engine evolve very quickly, so it's sometimes hard to keep everything in sync. Finally, the core layout engines have strong security requirements that are difficult to satisfy in a volunteer-driven situation...

Beyond volunteer-driven MathML developments

At that point, there are several options. First the lazy one: Give up with native math rendering, only focus on features that have impact on the widest Web audience (i.e. those that would allow browser vendors to get more market share and thus increase their profit), thank the math people for creating the Web and kindly ask them to use whatever hacks they can imagine to display equations on the Web. Of course as a Mozillian, I think people must decide the Web they want and thus exclude this option.

Next there is the ingenuous option: Expect that browser companies will understand the importance of math-on-the-Web and start investing seriously in MathML support. However, Netscape and Microsoft rejected the <MATH> tag from the 1995 HTML 3.0 draft and the browser companies have kept repeating they would only rely on volunteer contributions to move MathML forward, despite the repeated requests from MathML folks and other scientific communities. So that option is excluded too, at least in the short to medium term.

So it remains the ambitious option: Math people and other interested parties must get together and try to fund native MathML developments. Despite the effort of my manager at MathJax to convince partners and raise funds, my situation has not changed much since April and it is not clear when/if the MathJax Consortium can take the lead in native MathML developments. Given my expertise in Gecko, WebKit and MathML, I feel the duty to do something. Hence I wish to reorganize my work time: Decrease my involvement in MathJax core in order to increase my involvement in Gecko/WebKit developments. But I need the help of the community for that purpose. If you run a business with interest for math-on-the-Web and are willing to fund my work, then feel free to contact me directly by mail for further discussion. In the short term, I want to experiment with Crowd Funding as discussed in the next section. If this is successful we can think of a better organization for MathML developments in the long term.

Crowd Funding

Wikipedia defines Crowd funding as "the collective effort of individuals who network and pool their money, usually via the Internet, to support efforts initiated by other people or organizations". There are several Crowd Funding platforms with similar rule/interface. I am considering Catincan which is specialized in Open Source Crowd Funding, can be used by any backer/developer around the world, can rely on Bugzilla to track the bug status and seems to have good process to collect the fund from backers and to pay developers. You can easily login to the Catincan Website if you have a GitHub, Facebook or Google account (apparently Persona is not supported yet...). Finally, it seems to have a communication interface between backers and developers, so that everybody can follow the development on the funded features.

One distinctive feature of catincan is that only well-established Open Source projects can be funded and only developers from these projects can propose and work on the new features ; so that backers can trust that the features will be implemented. Of course, I have been working on Gecko, WebKit and MathML projects so I hope people believe I sincerely want to improve MathML support in browsers and that I have the skills to do so ;-)

As said in my previous blog post, it is not clear at all (at least to me) whether Crowd Funding can be a reliable method, but it is worth trying. There are many individuals and small businesses showing interest in MathML, without the technical knowledge or appropriate staff to improve MathML in browsers. So if each one fund a small amount of money, perhaps we can get something.

One constraint is that each feature has 60 days to reach the funding goal. I do not have any idea about how many people are willing to contribute to MathML and how much money they can give. The statistical sample of projects currently funded is too small to extract relevant information. However, I essentially see two options: Either propose small features and split the big ones in small steps, so that each catincat submission will need less work/money and improvements will be progressive with regular feedback to backers ; or propose larger features so they look more attractive and exciting to people and will require less frequent submissions to catincat. At the beginning, I plan to start with the former and if the crowd funding is successful perhaps try the latter.

Status in Open Source Layout Engines

Note: Obviously, Open Source Crowd Funding does not apply to Internet Explorer, which is the one main rendering engine not mentioned below. Although Microsoft has done a great job on MathML for Microsoft Word, they did not give any public statement about MathML in Internet Explorer and all the bug reports for MathML have been resolved "by design" so far. If you are interested in MathML rendering and accessibility in Internet Explorer, please check Design Science blog for the latest updates and tools.

Blink

Note: I am actually focusing on the history of Chromium here but of course there are other Blink-based browsers. Note that programs like QtWebEngine (formerly WebKit-based) or Opera (formerly Presto-based) lost the opportunity to get MathML support when they switched to Blink.

Alex Milowski and François Sausset's first MathML implementation did not pass Google's security review. Dave Barton fixed many issues in that implementation and as far as I know, there were not any known security vulnerabilities when Dave submitted his last version. MathML was enabled in Chrome 24 but Chrome developers had some concerns about the design of the MathML implementation in WebKit, which indeed violated some assumptions of WebKit layout code. So MathML was disabled in Chrome 25 and as said in the introduction, the source code was entirely removed when they forked.

Currently, the Chromium Dashboard indicates that MathML is shipped in Firefox/Safari, has positive feedback from developers and is an established standard ; but the Chromium status remains "No active development". If I understand correctly, Google's official position is that they do not plan to invest in MathML development but will accept external contributions and may re-enable MathML when it is ready (for some sense of "ready" to be defined). Given the MathML story in Chrome, it seems really unlikely that any volunteer will magically show up and be willing to submit a MathML patch. Incidentally, note the interesting work of the ChromeVox team regarding MathML accessibility: Their recent video provides a good overview of what they achieve (where Volker Sorge politely regrets that "MathML is not implemented in all browsers").

Although Google's design concerns have now been addressed in WebKit, one most serious remark from one Google engineer is that the WebKit MathML implementation is of too low quality to be shipped so they just prefer to have no MathML at all. As a consequence, the best short term strategy seems to be improving WebKit MathML support and, once it is good enough, to submit a patch to Google. The immediate corollary is that if you wish to see MathML in Chrome or other Blink-based browsers you should help WebKit MathML development. See the next section for more details.

Chromatic chromatic

Actually, I tried to import MathML into Blink one day this summer. However, there were divergences between the WebKit and Blink code bases that made that a bit difficult. I do not plan to try again anytime soon, but if someone is interested, I have published my script and patch on GitHub. Note there may be even more divergences now and the patch is certainly bit-rotten. I also thought about creating/maintaining a "Chromatic" browser (Chrome + mathematics) that would be a temporary fork to let Blink users benefit from native MathML until it is integrated back in Blink. But at the moment, that would probably be too much effort for one person and I would prefer to focus on WebKit/Gecko developments for now.

WebKit

The situation in WebKit is much better. As said before, Google's concerns are now addressed and MathML will be enabled again in all WebKit releases soon. Martin Robinson is interested in helping the MathML developments in WebKit and his knowledge of fonts will be important to improve operator stretching, which is one of the biggest issue right now. One new volunteer contributor, Gurpreet Kaur, also started to do some work on WebKit like support for the *scriptshifts attributes or for the <menclose> element. Last but not least, a couple of Apple/WebKit developers reviewed and accepted patches and even helped to fix a few bugs, which made possible to move development forward.

WebKineTic

When he was still working on WebKit, Dave Barton opened bug 99623 to track the top priorities. When the bugs below and their related dependencies are fixed, I think the rendering in WebKit will be good enough to be usable for advanced math notations and WebKit will pass the MathML Acid 1 test.

  • Bug 44208: For example, in expression like sin(x), the "x" should be in italic but not the "sin". This is actually slightly more complicated: It says when the default mathvariant value must be normal/italic. mathvariant is more like the text-transform CSS property in the sense that it remaps some characters to the corresponding mathematical characters (italic, bold, fraktur, double-struck...) for example A (mathvariant=fraktur A) should render exactly the same as 𝔄 (U+1D504). By the way, there is the related bug 24230 on Windows, that prevents to use plane 1 characters. The best solution will probably be to implement mathvariant correctly. See also Gecko's ongoing work by James Kitchener below.
  • Bug 99618: Implement <mmultiscripts>, that allows expressions like C614 or Rij;j=12S;i. As said in the introduction, this is fixed in WebKit Nightly.
  • Bug 99614: Support for stretchy operators like in (z1+z2¯3)4. Currently, WebKit can only stretch operators vertically using a few Unicode constructions like ⎛ (U+239B) + ⎜ (U+239C) + ⎝ (U+239D) for the left parenthesis. Essentially only similar delimiters like brackets, braces etc are supported. For small sizes like ( or for large operators like n2 it is necessary to use non-unicode glyphs in various math fonts, but this is not possible in WebKit MathML yet. All of this will require a fair amount of work: implementing horizontal stretching, font-specific stuff, largeop/symmetric properties etc
  • Bug 99620: Implement the operator dictionary. Currently, WebKit treats all the operators the same way, so for example it will use the same 0.2em spacing before and after parenthesis, equal sign or invisible operators in e.g. f(x)=x2. Instead it should use the information provided by the MathML operator dictionary. This dictionary also specifies whether operators are stretchy, symmetric or largeop and thus is related to the previous point.
  • Bug 119038: Use the code for vertical stretchy operators to draw the radical symbols in roots like 23. Currently, WebKit uses graphic primitives which do not give a really good rendering.
  • Bug 115610: Implement <mspace> which is used by many MathML generators to do some spacing in mathematical formulas. As said in the introduction, this is fixed in WebKit Nightly.

In order to pass the Mozilla MathML torture tests, at least displaystyle and scriptlevel must be implemented too, probably as internal CSS properties. This should also allow to pass Joe Java's MathML test, although that one relies on the infamous <mfenced> that duplicates the stretchy operator features and is implemented inconsistently in rendering engines. I think passing the MathML Acid 2 test will require slightly more effort, but I expect this goal to be achievable if I have more time to work on WebKit:

  • Bug 115610: Implement <mspace>. Fixed!
  • Bug 120164: Implement negative spacing for <mspace> (I have an experimental patch).
  • Bug 85730: Implement <mpadded>, which is also used by MathML generators to do some tweaking of formulas. I have only done some experiments, that would be a generalization of <mspace>
  • Bug 85733: Implement the href attribute ; well I guess the name is explicit enough to understand what it is used for! I only have some experimental patch here too. That would be mimicing what is done in SVG or HTML.
  • Bug 120059 and bug 100626: Implement <maction> (at least partially) and <semantics>, which have been asked by long-time MathML users Jacques Distler and Michael Kohlhase. I have patches ready for that and this could be fixed relatively soon, I just need to find time to finish the work.

In general passing the MathML Acid 2 test is not too hard, you merely only need to implement those few MathML elements whose exact rendering is clearly defined by the MathML specification. Passing the MathML Acid 3 test is not expected in the medium term. However, the score will naturally increase while we improve WebKit MathML implementation. The priority is to implement what is currently known to be important to users. To give examples of bugs not previously mentioned: Implementing menclose or fixing various DOM issues like bugs 57695, 57696 or 107392.

More advanced features like those mentioned in the next section for Gecko are probably worth considering later (Open type MATH, linebreaking, mlabeledtr...). It is worth noting that Apple has already done some work on accessibility (with MathML being readable by VoiceOver in iOS7), authoring and EPUB (MathML is enabled in WebKit-based ebook readers and ibooks-author has an integrated LaTeX-to-MathML converter).

Gecko

Mathzilla

In general I think I have a good relationship with the Mozilla community and most people have respect for the work that has been done by volunteers for almost 15 years now. The situation has greatly improved since I joined the project, at that time some people claimed the Mozilla MathML project was dead after Roger Sidge's departure. One important point is that Karl Tomlinson has worked on repairing the MathML support when Roger Sidge left the project. Hence there is at least one Mozilla employee with good knowledge of MathML who can review the volunteer patches. Another key ingredient is the work that has recently been made by Mozilla to increase engagement of the volunteer community like good documentation on MDN, the #Introduction channel, Josh Matthews' mentored bugs and of course programs like GSOC. However, as said above, it is one thing to attract enthusiastic contributors and another thing to get long-term contributors who can work independently on more advanced features. So let's go back to my latest Roadmap for the Mozilla MathML Project and see what has been accomplished for one year:

  • Font support: Dmitry Shachnev created a Debian package for the MathJax fonts and Mike Hommey added MathJax and Asana fonts in the list of suggested packages for Iceweasel. The STIX fonts have also been updated in Fedora and are installed by default on Mac OS X Lion (10.7). For Linux distributions, it would be helpful to implement Auto Installation Support. The bug to add mathematical fonts to Android has been assigned in June but no more progress has happened so far. Henri Sinoven opened a bug for FirefoxOS but there has not been any progress there either. I had some patches to restore the "missing MathML fonts" warning (using an information bar) but it was refused by Firefox reviewers. However, the code to detect missing MathML font could still be used for the similar bug 648548, which also seems inactive since January. There are still some issues on the MathJax side that prevent to integrate Web fonts for the native MathML output mode. So at the moment the solution is still to inform visitors about MathML fonts or to add MathML Web fonts to your Web site. Khaled Hosny (font and LaTeX expert) recently updated my patches to prepare the support for Open Type fonts and he offered to help on that feature. After James Kitchener's work on mathvariant, we realized that we will probably need to provide Arabic mathematical fonts too.
  • Spacing: Xuan Hu continued to work on <mpadded> improvements and I think his patch is close to be accepted. Quentin Headen has done some progress on <mtable> before focusing on his InstantBird GSOC project. He is still far from being able to work on mtable@rowspacing/columnspacing but a work around for that has been added to MathJax. I fixed the negative space regression which was missing to pass the MathML Acid 2 test and is used in MathJax. Again, Khaled Hosny is willing to help to use the spacing of the Open Type MATH, but that will still be a lot of work.
  • <mlabeledtr>: A work around for native MathML has been added in MathJax.
  • Linebreaking: No progress except that I have worked on fixing a bug with intrinsic width computation. The unrelated printing issues mentioned in the blog post have been fixed, though.
  • Operator Stretching: No progress. I tried to analyze the regression more carefully, but nothing is ready yet.
  • Tabular elements: As said above, Quentin Headen has worked a bit on cleaning up <mtable> but not much improvements on that feature so far.
  • Token elements: My patch for <ms> landed and I have done significant progress on the bad measurement of intrinsic width for token elements (however, the fix only seems to work on Linux right now). James Kitchener has taken over my work on improving our mathvariant support and doing related refactoring of the code. I am confident that he will be able to have something ready soon. The primes in exponents should render correctly with MathJax fonts but for other math fonts we will have to do some glyph substitutions.
  • Dynamic MathML: No progress here but there are not so many bugs regarding Javascript+MathML, so that should not be too serious.
  • Documentation: It is now possible to use MathML in code sample or directly in the source code. The MathML project pages have been entirely migrated to MDN. Also, Florian Scholz has recently been hired by Mozilla as a documentation writer (congrats!) and will in particular continue the work he started as a volunteer to document MathML on MDN.

I apologize to volunteers who worked on bugs that are not mentioned above or who are doing documentation or testing that do not appear here. For a complete list of activity since September 2012, Bugzilla is your friend. There are two ways to consider the progress above. If you see the glass half full, then you see that several people have continued the work on various MathML issues, they have made some progress and we now pass the MathML Acid 2 test. If you see the glass half empty, then you see that most issues have not been addressed yet and in particular those that are blocking the native MathML to be enabled in MathJax: bug 687807, bug 415413, the math font issues discussed in the first point, and perhaps linebreaking too. That is why I believe we should go beyond volunteer-driven MathML developments.

Most of the bugs mentioned above are tested by the MathML Acid 3 tests and we will win a few points when they are fixed. Again, passing MathML Acid 3 test is not a goal by itself so let's consider what are the big remaining areas it contains:

  • Improving Tabular Elements and Operator Stretching, which are obviously important and used a lot in e.g. MathJax.
  • Linebreaking, which as I said is likely to become fundamental with small screens and ebooks.
  • Elementary Mathematics (you know addition, subtraction, multiplication, and division that kids learn), which I suspect will be important for educational tools and ebooks.
  • Alignment: This is the one part of MathML that I am not entirely sure is relevant to work on in the short term. I understand it is useful for advanced layout but most MathML tools currently just rely on tables to do that job and as far as I know the only important engine that implements that is MathPlayer.

Finally there are other features outside the MathML rendering engines that I also find important but for which I have less expertise:

  • Transferring MathML that is implementing copy/cut/drag and paste. Currently, we can do that by treating MathML as normal HTML5 code or by using the "show MathML source" feature and copying the source code. However, it would be best to implement a standard way to communicate with other MathML applications like Microsoft Word, Mathematica, Mapple, Windows' Handwriting panel etc I wrote some work-in-progress patches last year.
  • Authoring MathML: Essentially implementing things like deletion, insertion etc maybe simple MathML token creation ; in Gecko's core editor, which is used by BlueGriffon, KompoZer, SeaMonkey, Thunderbird or even MDN. Other things like integrating Javascript parsers (e.g. ASCIIMath) or equation panels with buttons like are probably better done at the higher JS/HTML/XUL level. Daniel Glazman already wrote math input panels for BlueGriffon and Thunderbird.
  • MathML Accessibility: This is one important application of MathML for which there is strong demand and where Mozilla is behind the competitors. James Teh started some experimental work on his NVDA tool before the summit.
  • EPUB reader for FirefoxOS (and other mobile platforms): During the "Co-creating Action Plans" session, the Mozilla Taipei people were thinking about missing features for FirefoxOS and this idea about EPUB reader was my modest contribution. There are a few EPUB readers relying on Gecko and it would be good to check if they work in FirefoxOS and if they could be integrated by default, just like Apple has iBooks. BTW, there is a version of BlueGriffon that can edit EPUB books.

Conclusion

I hope I have convinced some of the readers about the need to fund MathMLin browsers. There is a lot of MathML work to do on Gecko and WebKit but both projects have volunteers and core engineers who are willing to help. There are also several individuals / companies relying on MathML support in rendering engines for their projects and could support the MathML developments in some way. I am willing to put more of my time on Gecko and WebKit developments, but I need financial help for that purpose. I'm proposing catincan Crowd Funding in the short term so that anyone can contribute at the appropriate level, but other alternatives to fund the MathML development can be found like asking Peter Krautzberger about native MathML funding in MathJax, discussing with Igalia about funding Martin Robinson to work more on WebKit MathML or contacting me directly to establish some kind of part-time consulting agreement.

Please leave a comment on this blog or send me a private mail, if you agree that funding MathML in browsers is important, if you like the crowd funding idea and plan to contribute ; or if you have any opinions about alternative funding options. Also, please tell me what seem to be the priority for you and your projects among what I have mentioned above (layout engines, features etc) or among others that I may have forgotten. Of course, any other constructive comment to help MathML support in browsers is welcome. I plan to submit features on catincan soon, once I have more feedback on what people are interested in. Thank you!

By fredw at October 15, 2013 09:05 PM

October 07, 2013

Post-Summit Thoughts on the MathML Project

Frédéric Wang

I'm back from a great Mozilla Summit 2013 and I'd just like to write a quick blog post about the MathML booths at the Innovation Fairs. I did not have the opportunity to talk with the MathML people who ran the booth at Santa Clara yet. However, everything went pretty well at Brussels, modulo of course some demos failing when done in live... If you are interested, the slides and other resources are available on my GitHub page.

Many Mozillians did not know about MathML or that it had been available in Gecko since the early days of the Mozilla project. Many people who use math (or just knowing someone who does) were curious about that feature and excited about the MathML potentials. I appreciated to get this positive feedback from Mozillians willing to use math on the Web and related media, instead of the scorn or hatred I sometimes see by misinformed people. I expect to provide more updates on LaTeXML, MediaWiki Math and MathJax when their next versions are released. The Gecko MathML support improves slowly but there has been interesting work by James Kitchener recently that I'd like to mention too.

MathZilla on blackboard

Let's do an estimation à la Fermi: only a few volunteers have been contributing regularly and simultaneously to MathML in Gecko while most Mozilla-funded Gecko projects have certainly development teams that are 3 times as large. Let's be optimistic and assume that these volunteers have been able to dedicate a mean of 1 work day per week, compared to 5 for full-time staff. Given that the Mozilla MathML project will celebrate its 15 years next May, that means that the volunteer work transposed in terms of paid-staff time is only 15 35 = 1 year. To be honest, I'm disregarding here the great work made by the Mozilla NZ team around 2007 to repair MathML after the Cairo migration. But still, what we have achieved in quality and completeness with such limited resources and time is really impressive.

As someone told me at the MathML booth, it's really frustating that something that is so important for the small portion of math-educated people is ignored because it is useless for the vast majority of people. This is not entirely true, since even elementary mathematics taught at school like the one of this blog post are not easily expressed with standard HTML and even less in a way accessible to people with visual disabilities. However, it summarizes well the feeling MathML folks had when they tried to convince Google to accept the volunteer work on MathML, despite its low quality.

As explained at the Summit Sessions, Mozilla's mission is different and the goal is to give people the right to control the Web they want. The MathML project is perhaps one of the oldest and successful volunteer-driven Mozilla project that is still active and demonstrates concretely the idea of the Mozilla's mission with e.g. the work of Roger Sidge who started to write the MathML implementation when Netscape opened its source code or the one of Florian Scholz who made MDN one of the most complete Web resource for MathML.

Mozilla Corporation has kept saying they don't want to invest in MathML developments and the focus right now is clearly on other features like FirefoxOS. Even projects that have a larger audience than the MathML support like the mail client or the editor are not in the priorities so someone else definitely need to step in for MathML. I've tried various methods, with more or less success, to boost the MathML developments like mentoring a GSoC project, funding a summer internship or relying on mentored bugs. I'm now considering crowd funding to help the MathML developments in Gecko (and WebKit). I don't want to do another Fermi estimation now but at first that looks like a very unreliable method. The only revenue generated by the MathML project so far are the 2 100 π 100 = 2 3.14 = 6.28 dollars to the Mozilla Fundation via contributions to my MathML-fonts add-on, so it's hard to get an idea of how much people would contribute to the Gecko implementaton. However, that makes sense since the only people who showed interest in native MathML support so far are individuals or small businesses (e.g. working on EPUB or accessibility) and I think it's worth trying it anyway. That's definitely something I'll consider after MathJax 2.3 is released...

By fredw at October 07, 2013 04:18 PM

August 27, 2013

HTML Alchemy – Combining CSS Shapes with CSS Regions

Adobe Web Platform

Note: Support for shape-inside is only available until the following nightly builds: WebKit r166290 (2014-03-26); Chromium 260092 (2014-03-28).


I have been working on rendering for almost a year now. Since I landed the initial implementation of Shapes on Regions in both Blink and WebKit, I’m incredibly excited to talk a little bit about these features and how you can combine them together.

Mad_scientist

Don’t know what CSS Regions and Shapes are? Start here!

The first ingredient in my HTML alchemy kitchen is CSS Regions. With CSS Regions, you can flow content into multiple styled containers, which gives you enormous creative power to make magazine style layouts. The second ingredient is CSS Shapes, which gives you the ability to wrap content inside or outside any shape. In this post I’ll talk about the “shape-inside” CSS property, which allows us to wrap content inside an arbitrary shape.

Let’s grab a bowl and mix these two features together, CSS Regions and CSS Shapes to produce some really interesting layouts!

In the latest Chrome Canary and Safari WebKit Nightly, after enabling the required experimental features, you can flow content continuously through multiple kinds of shapes. This rocks! You can step out from the rectangular text flow world and break up text into multiple, non-rectangular shapes.

Demo

If you already have the latest Chrome Canary/Safari WebKit Nightly, you can just go ahead and try a simple example on codepen.io. If you are too lazy, or if you want to extend your mouse button life by saving a few button clicks, you can continue reading.


iBuyd3

In the picture above we see that the “Lorem ipsum” story flows through 4 different, colorful regions. There is a circle shape on each of the first two fixed size regions. Check out the code below to see how we apply the shape to the region. It’s pretty straightforward, right?
#region1, #region2 {
    -webkit-flow-from: flow;
    background-color: yellow;
    width: 200px;
    height: 200px;
    -webkit-shape-inside: circle(50%, 50%, 50%);
}
The content flows into the third (percentage sized) region, which represents a heart (drawn by me, all rights reserved). I defined the heart’s coordinates in percentages, so the heart will stretch as you resize the window.
#region3 {
    -webkit-flow-from: flow;
    width: 50%;
    height: 400px;
    background-color: #EE99bb;
    -webkit-shape-inside: polygon(11.17% 10.25%,2.50% 30.56%,3.92% 55.34%,12.33% 68.87%,26.67% 82.62%,49.33% 101.25%,73.50% 76.82%,85.17% 65.63%,91.63% 55.51%,97.10% 31.32%,85.79% 10.21%,72.47% 5.35%,55.53% 14.12%,48.58% 27.88%,41.79% 13.72%,27.50% 5.57%);
}

The content that doesn’t fit in the first three regions flows into the fourth region. The fourth region (see the retro-blue background color) has its CSS width and height set to auto, so it grows to fit the remaining content.

Real world examples

After trying the demo and checking out the links above, I’m sure you’ll see the opportunities for using shape-inside with regions in your next design. If you have some thoughts on this topic, don’t hesitate to comment. Please keep in mind that these features are under development, and you might run into bugs. If you do, you should report them on WebKit’s Bugzilla for Safari or Chromium’s issue tracker for Chrome. Thanks for reading!

By Zoltan Horvath at August 27, 2013 04:00 PM

August 06, 2013

WebGL, at last!

Brent Fulgham

It's been a long time since I've written an update -- but my lack of blog posting is not an indication of a lack of progress in WebKit or the WinCairo port. Since I left my former employer (who *still* hasn't gotten around to updating the build machine I set up there), we've:

  • Migrated from Visual Studio 2005 to Visual Studio 2010 (and soon, VS2012)
  • Enabled New-run-webkit-tests
  • Updated the WinCairo Support Libraries to support 64-bit builds
  • Integrated a ton of cURL improvements and extensions thanks to the TideSDK guys 
  • and ...
... thanks to the hard work of Alex Christensen, brought up WebGL on the WinCairo port.  This is a little exciting for me, because it marks the first time (I can recall) where the WinCairo port actually gained a feature that was not already part of the core Apple Windows port.



The changes needed to see these circa-1992 graphics in all their three-dimensional glory are already landed in the WebKit tree.  You just need to:

  1. Enable the libEGL, libGLESv2, translator_common, translator_glsl, and translator_hlsl for the WinCairo build (they are currently turned off).
  2. Make the following change to WTF/wtf/FeatureDefines.h: 

Brent Fulgham@WIN7-VM ~/WebKit/Source/WTF/wtf
$ svn diff
Index: FeatureDefines.h
===================================================================
--- FeatureDefines.h    (revision 153733)
+++ FeatureDefines.h    (working copy)
@@ -245,6 +245,13 @@
 #define ENABLE_VIEW_MODE_CSS_MEDIA 0
 #endif

+#define ENABLE_WEBGL 1
+#define WTF_USE_3D_GRAPHICS 1
+#define WTF_USE_OPENGL 1
+#define WTF_USE_OPENGL_ES_2 1
+#define WTF_USE_EGL 1
+#define WTF_USE_GRAPHICS_SURFACE 1
+
 #endif /* PLATFORM(WIN_CAIRO) */

 /* --------- EFL port (Unix) --------- */

Performance is a little ragged, but we hope to improve that in the near future.

We have plenty of more plans for the future, including full 64-bit support (soon), and hopefully some improvements to the WinLauncher application to make it a little more useful.

As always, if you would like to help out,

By Brent Fulgham (noreply@blogger.com) at August 06, 2013 05:53 AM

May 15, 2013

CSS Level 3 Text Decoration on WebKit and Blink – status

Bruno de Oliveira Abinader

It’s been a while since I wrote the last post about progress on implementing CSS Level 3 Text Decoration features in WebKit. I’ve been involved with other projects but now I can finally resume the work in cooperation with my colleague from basysKom, Lamarque Souza. So far we have implemented:

  • text-decoration-line (link)
  • text-decoration-style (link)
  • text-decoration-color (link)
  • text-underline-position (link)

These properties are currently available under -webkit- prefix on WebKit, and guarded by a feature flag - CSS3_TEXT – which is enabled by default on both EFL and GTK ports. On Blink, plans are to get these properties unprefixed and under a runtime flag, which can be activated by enabling the “Experimental WebKit Features” (updated to “Experimental Web Platform Features” in latest builds) flag – see chrome://flags inside Google Chrome/Chromium). There are still some Skia-related issues to fix on Blink to enable proper dashed and dotted text decoration styles to be displayed. In the near future, we shall also have the text-decoration shorthand as specified on CSS Level 3 specification.

See below a summary of things I plan to finish in the near future:

  • [webkit] Property text-decoration-line now accepts blink as valid value
  • [blink] Fix implementation of dashed and dotted styles on Skia
  • [blink] Fix an issue where previous Skia stroke styles were used when rendering paint decorations
  • [blink] Implement CSS3_TEXT as a runtime flag
  • [blink] Property text-decoration-line now accepts blink as valid value
  • [blink] Implement support for text-decoration shorthand
  • [webkit] Implement support for text-decoration shorthand

Note: Please do not confuse text-decoration‘s blink value with Blink project :)

Stay tuned for further updates!

By Bruno Abinader at May 15, 2013 04:52 PM

May 03, 2013

Firefox Nightly passes the Acid2 test

Frédéric Wang

Some updates on the MathML Acid Tests... First the patch for bug 717546 landed in Nightly and thus Gecko is now the first layout engine to pass the MathML Acid2 test. Here is a screenshot that should look familiar:

MathML Acid2, Nightly

As you know, Google developers forked Webkit and decided to remove from Blink all the code (including MathML) on which they don't plan to work in the short term. As a comparison, here is how the MathML Acid2 test looks like in Chrome Canary:

MathML Acid 2 Test, Canary

Next, someone reported that Firefox Mac got more errors in the MathML Acid3 test. I was already aware of some shortcomings anyway and thus took the opportunity to rewrite the tests with a better error tolerance. The changes also fixed some measurement issues with auto resizing on mobile platforms or when the zoom level is not set to the default. I also made the tests for stretchy operators more reliable and as a consequence, Gecko lost two points: the new score is 60/100. I still need to review and describe the tests and hope I won't find more mistakes.

Finally, I also added a MathML Acid1 test. It does not really look like the "classical" Acid1 test and is not "automated", in the sense that a reader must carefully (and in a subjective way) check the basic requirements. But at least it provides a small test in the spirit of CSS Acid 1: all 100%-conformant HTML 5 agents should be able to render these very elementary MathML expressions. Note that the formulas in the MathML Acid1 test are supposed to express mathematical properties of boxes from the CSS Acid1 test.

By fredw at May 03, 2013 12:43 PM

March 27, 2013

Freeing the Floats of the Future From the Tyranny of the Rectangle

Adobe Web Platform

With modern web layout you can have your content laid out in whatever shape you want as long as it’s a rectangle. Designers in other media have long been able to have text and other content lay out inside and around arbitrarily complex shapes. The CSS Exclusions, CSS Shapes Level 1, and CSS Shapes Level 2 specifications aim to bring this capability to the web.

While these features aren’t widely available yet, implementation is progressing and it’s already possible to try out some of the features yourself. Internet Explorer 10 has an implementation of the exclusions processing model, so you can try out exclusions in IE 10 today.

At Adobe we have been focusing on implementing the shapes specification. We began with an implementation of shape-inside and now have a working implementation of the shape-outside property on floats. We have been building our implementation in WebKit, so the easiest way to try it out yourself is to download a copy of Chrome Canary. Once you have Canary, enable Experimental Web Platform Features and go wild!

What is shape-outside?

“Now hold up there,” you may be thinking, “I don’t even know what a shape-outside is and you want me to read this crazy incomprehensible specification thing to know what it is!?!”

Well you’ll be happy to know that it really isn’t that complex, especially in the case of floats. When an element is floated, inline content avoids the floated element. Content flows around the margin box of the element as defined by the CSS box model. The shape-outside CSS property allows you to tell the browser to use a specified shape instead of the margin box when wrapping content around the floating element.

CSS Exclusions

The current implementation allows for rectangles, rounded rectangles, circles, ellipses, and polygons. While this gives a lot of flexibility, eventually you will be able to use a SVG path or the alpha channel of an image to make it easier to create complex shapes.

How do I use it?

First, you need to get a copy of Chrome Canary and then enable Experimental Web Platform features. Once you have that, load up this post in Chrome Canary so that you can click on the images below to see a live example of the code. Even better, the examples are on Codepen, so you can and should play with them yourself and see what interesting things you can come up with.

Note that in this post and the examples I use the unprefixed shape-outside property.
If you want to test these examples outside of my Codepen then you will need to use the prefixed -webkit-shape-outside property or use (which is a built in option in Codepen).

We’ll start with a HTML document with some content and a float. Currently shape-outside only works on floating elements, so those are the ones to concentrate on. For example: (click on the image to see the code)

HTML without shape-outside

You can now add the shape-outside property to the style for your floats.

.float {
  shape-outside: circle(50%, 50%, 50%);
}

A circle is much more interesting than a standard rectangle, don’t you think? This circle is centered in the middle of the float and has a radius that is half the width of the float. The effect on the layout is something like this:

shape-outside circle

While percentages were used for this circle, you can use any CSS unit you like to specify the shape. All of the relative units are relative to the dimensions of element where the shape-outside is specified.

Supported shapes

Circles are cool and all, but I promised you other shapes, and I will deliver. There are four types of shapes that are supported by the current shape-outside implementation: rectangle, circle, ellipse, and polygon.

rectangle

You have the ability to specify a shape-outside that is a fairly standard rectangle:

shape-outside: rectangle(x, y, width, height);

The x and y parameters specify the coordinates of the top-left corner of the rectangle. This coordinate is in relation to the top-left corner of the floating element’s content box. Because of the way this interacts with the rules of float positioning, setting these to anything other than 0 causes an effect that is similar to relatively positioning the float’s content. (Explaining this is beyond the scope of this post.)

The width and height parameters should be self-explanatory: they are the width and height of the resulting rectangle.

Where things get interesting is with the six-argument form of rectangle:

shape-outside: rectangle(x, y, width, height, rx, ry);

The first four arguments are the same as explained above, but the last two specify corner radii in the horizontal (rx) and vertical (ry) directions. This not only allows the creation of rounded rectangles, you can create circles and ellipses as well. (Just like with [border-radius][border-radius].)

Here’s an example of a rectangle, a rounded rectangle, a circle, and an ellipse using just rectangle syntax:

shape-outside rectangle

If you’re reading this in Chrome Canary with exclusions turned on, play around with this demo and see what other things you can do with the rectangles.

circle

I already showed you a simple circle demo and you’ll be happy to know that’s pretty much all there is to know about circles:

shape-outside: circle(cx, cy, radius);

The cx and cy parameters specify the coordinates of the center of the circle. In most situations you’ll want to put them at the center of your box. Just like with rectangles moving this around can be useful, but it behaves similarly to relatively positioning the float’s content with respect to the shape.

The radius parameter is the radius of the resulting circle.

In case you’d like to see it again, here’s what a circle looks like:

shape-outside circle

While it is possible to create circles with rounded rectangles as described above, having a dedicated circle shape is much more convenient.

ellipse

Sometimes, you need to squish your circles and that’s where the ellipse comes in handy.

shape-outside: ellipse(cx, cy, rx, ry);

Just like a circle, an ellipse has cx and cy to specify the coordinates of its center and you will likely want to have them at the center of your float. And just like all the previous shapes, changing these around will cause the float’s content to position relative to your shape.

The rx and ry parameters will look familiar from the rounded rectangle case and they are exactly what you would expect: the horizontal and vertical radii of the ellipse.

Ellipses can be used to create circles (rx = ry) and rounded rectangles can be used to create ellipses, but it’s best to use the shape that directly suits your purpose. It’s much easier to read and maintain that way.

Here’s an example of using an ellipse shape:

shape-outside ellipse

polygon

Now here’s where things get really interesting. The polygon `shape-outside` allows you to specify an arbitrary polygonal shape for your float:

shape-outside: polygon(x1 y1, x2 y2, ... , xn yn);

The parameters of the polygon are the x and y coordinates of each vertex of the shape. You can have as many vertices as you would like.

Here’s an example of a simple polygon:

shape-outside triangle

Feel free to play with this and see what happens if you create more interesting shapes!

Putting content in the float

The previous examples all had divs without any content just to make it easier to read and understand the code, but a big motivation for shape-outside is to wrap around other content. Interesting layouts often involve wrapping text around images as this final example shows:

shape-outside with images

As usual, you should take a look and play with the code for this example of text wrapping around floated images. This is just the beginning of the possibilities, as you can put a shape outside on any floating element with any content you want inside.

Next steps

We are still hard at work on fixing bugs in the current implementation and implementing the rest of the features in the CSS Shapes Level 1 specification. We welcome your feedback on what is already implemented and also on the spec itself. If you are interested in becoming part of the process, you can raise issues with the current WebKit implementation by filing bugs in the WebKit bugzilla. If you have issues with the spec, those are best raised on the www-style mailing list. And of course, you can leave your feedback as comments on this post.

I hope that you enjoy experimenting with shape-outside and the other features we are currently working on.

By Bem Jones-Bey at March 27, 2013 05:10 PM

August 01, 2012

WebKit CSS3 text-decoration properties (preview)

Bruno de Oliveira Abinader

WebKit currently supports CSS Text Level 2.1 version of text-decoration property (link). This version treats only about the decoration line types (underline, overline, line-through and blink – the latter is not supported on WebKit).

The draft version of CSS Text Level 3 upgrades text-decoration (link) property as a shorthand to 3 newly added properties, named text-decoration-line (link), text-decoration-style (link) and text-decoration-color (link), and also adds text-decoration-skip (link) property.

Among other WebKit stuff I’ve been doing lately, this feature implementation is one of the most cool ones I’m enjoying implementing. I’ve grabbed the task of implementing all of these CSS3 text-decoration* properties on WebKit, and results are great so far!

As you can see below, these are the new text decoration styles (solid, double, dotted, dashed and wavy – the latter still requires platform support) available:

Text decoration style layout test results on Qt platform

And also specific text decoration colors can be set:

Text decoration color layout test results on Qt platform

These features (with exception to text-decoration-skip property) are already implemented on Firefox, thus it gets easier to compare results with different web engines. It is important to notice since CSS3 specification is still in development, all these properties have a -webkit- prefix (ie. -webkit-text-decoration), so text-decoration still maintains CSS2.1 specification requirements. The patches are being reviewed and will soon land upstream, let’s hope it will be soon!

By Bruno Abinader at August 01, 2012 09:58 PM

April 11, 2012

A guide for Qt5/WebKit2 development setup for Nokia N9 on Ubuntu Linux

Bruno de Oliveira Abinader

As part of my daily activities at basysKom on QtWebKit maintenance and development for Nokia devices, it is interesting to keep a track on latest developments circa QtWebKit. There is currently a promising project of a Qt5/WebKit2-based browser called Snowshoe mainly developed by my fellow friends from INdT which is completely open-source. This browser requires latest Qt5 and QtWebKit binaries and thus requires us to have a functional build system environment. There is a guide available on WebKit’s wiki (link) which is very helpful but lacks some information about compilation issues found when following the setup steps. So I am basing this guide from that wiki page and I hope that it gets updated soon :)

On this guide it is assumed the following:

  • All commands are issued on a Linux console. I am not aware of how this guide would work on other systems.
  • All commands are supposed to be issued inside base directory, unless expressely said otherwise (ie. cd <QT5_DIR>).
  • You might want to check if you have git and rsync packages installed in your system.

1. Install Qt SDK

In order to build Qt5 and QtWebKit for Nokia N9, you need to set up a cross-compiler. Thankfully, Qt SDK already comes with a working setup. Please download the online installer from Qt Downloads section (link).

NOTE: The offline installer comes with an outdated version of the MADDE target, which can be updated by running the script below and chosing “Update components” when asked:

$ ~/QtSDK/SDKMaintenanceTool

2. Directory setup

It is suggested (and actually required by some build scripts) to have a base directory which holds Qt5, Qt Components and WebKit project sources. The suggested base directory can be created by running:

$ mkdir -p ~/swork

NOTE: You can actually choose another directory name, but so far it is required by some scripts to have at least a symbolic link pointing to <HOME_DIR>/swork.

3. Download convenience scripts

3.1. browser-scripts

$ git clone https://github.com/resworb/scripts.git browser-scripts

3.2. rsync-scripts

$ wget http://trac.webkit.org/attachment/wiki/SettingUpDevelopmentEnvironmentForN9/rsync-scripts.tar.gz?format=raw
$ tar xzf rsync-scripts.tar.gz

4. Download required sources

4.1. testfonts

$ git clone git://gitorious.org/qtwebkit/testfonts.git

4.2. Qt5, QtComponents and WebKit

The script below when successfully run will create ~/swork/qt5, ~/swork/qtcomponents and ~/swork/webkit directories:

$ browser-scripts/clone-sources.sh --no-ssh

NOTE: You can also manually download sources, but remember to stick with the directory names described above.

5. Pre-build hacks

5.1. Qt5 translations

Qt5 translations are not being properly handled by cross-platform toolchain. This happens mainly because lrelease application is called to generate Qt message files, but since it is an ARMEL binary your system is probably not capable of running it natively (unless you have a misc_runner kernel module properly set, then you can safely skip this step). In this case, you can use lrelease from your system’s Qt binaries without any worries.

If you have a Scratchbox environment set, it is suggested for you to stop its service first:

$ sudo service scratchbox-core stop

Now you can manually generate Qt message files by running this:

$ cd ~/swork/qt5/qttranslations/translations
$ for file in `ls *ts`; do lrelease $file -qm `echo "$file" | sed 's/ts$/qm/'`; done

5.2. Disable jsondb-client tool

QtJsonDB module from Qt5 contains a tool called jsondb-client, which depends on libedit (not available on MADDE target). It is safe to disable its compilation for now:

$ sed -i 's/jsondb-client//' ~/swork/qt5/qtjsondb/tools/tools.pro

5.3. Create missing symbolic links

Unfortunately Qt5 build system is not robust enough to support our cross-compilation environment, so some symbolic links are required on MADDE to avoid compilation errors (where <USER> is your system user name):

$ ln -s ~/swork/qt5/qtbase/include ~/QtSDK/Madde/sysroots/harmattan_sysroot_10.2011.34-1_slim/home/<USER>/swork/qt5/qtbase
$ ln -s ~/swork/qt5/qtbase/mkspecs ~/QtSDK/Madde/sysroots/harmattan_sysroot_10.2011.34-1_slim/home/<USER>/swork/qt5/mkspecs

6. Build sources

You can execute the script that will build all sources using cross-compilation setup:

$ browser-scripts/build-sources.sh --cross-compile

If everything went well, you now have the most up-to-date binaries for Qt5/WebKit2 development for Nokia N9. Please have a look at WebKit’s wiki for more information about how to update sources after a previous build and information on how to keep files in sync with device. The guide assumes PR1.1 firmware for N9 device, which is already outdated, so I might come up next with updated instructions on how to safely sync files to your PR1.2-enabled device.

That’s all for now, I appreciate your comments and feedback!

By Bruno Abinader at April 11, 2012 07:18 AM

March 10, 2012

WebKitGTK+ Debian packaging repository changes

Gustavo Noronha

For a while now the git repository used for packaging WebKitGTK+ has been broken. Broken as in nobody was able to clone it. In addition to that, the packaging workflow had been changing over time, from a track-upstream-git/patches applied one to a import-orig-only/patches-not-applied one.

After spending some more time trying to unbreak the repository for the third time I decided it might be a good time for a clean up. I created a new repository, imported all upstream versions for series 1.2.x (which is in squeeze), 1.6.x (unstable), and 1.7.x (experimental). I also imported packaging-related commis for those versions using git format-patch and black magic.

One of the good things about doing this move, and which should make hacking the WebKitGTK+ debian package more pleasant and accessible can be seen here:


kov@goiaba ~/s/debian-webkit> du -sh webkit/.git webkit.old/.git
27M webkit/.git
1.6G webkit.old/.git

If you care about the old repository, it’s on git.debian.org still, named old-webkit.git. Enjoy!

By kov at March 10, 2012 05:32 PM

December 07, 2011

WebKitGTK+ hackfest \o/

Gustavo Noronha

It’s been a couple days since I returned from this year’s WebKitGTK+ hackfest in A Coruña, Spain. The weather was very nice, not too cold and not too rainy, we had great food, great drinks and I got to meet new people, and hang out with old friends, which is always great!

Hackfest black board, photo by Mario

I think this was a very productive hackfest, and as usual a very well organized one! Thanks to the GNOME Foundation for the travel sponsorship, to our friends at Igalia for doing an awesome job at making it happen, and to Collabora for sponsoring it and granting me the time to go there! We got a lot done, and although, as usual, our goals list had many items not crossed, we did cross a few very important ones. I took part in discussions about the new WebKit2 APIs, got to know the new design for GNOME’s Web application, which looks great, discussed about Accelerated Compositing along with Joone, Alex, Nayan and Martin Robinson, hacked libsoup a bit to port the multipart/x-mixed-replace patch I wrote to the awesome gio-based infrastructure Dan Winship is building, and some random misc.

The biggest chunk of time, though, ended up being devoted to a very uninteresting (to outsiders, at least), but very important task: making it possible to more easily reproduce our test results. TL;DR? We made our bots’ and development builds use jhbuild to automatically install dependencies; if you’re using tarballs, don’t worry, your usual autogen/configure/make/make install have not been touched. Now to the more verbose version!

The need

Our three build slaves reporting a few failures

For a couple years now we have supported an increasingly complex and very demanding automated testing infrastructure. We have three buildbot slaves, one provided by Collabora (which I maintain), and two provided by Igalia (maintained by their WebKitGTK+ folks). Those bots build as many check ins as possible with 3 different configurations: 32 bits release, 64 bits release, and 64 bits debug.

In addition to those, we have another bot called the EWS, or Early Warning System. There are two of those at this moment: one VM provided by Collabora and my desktop, provided by myself. These bots build every patch uploaded to the bugzilla, and report build failures or passes (you can see the green bubbles). They are very important to our development process because if the patch causes a build failure for our port people can often know that before landing, and try fixes by uploading them to bugzilla instead of doing additional commits. And people are usually very receptive to waiting for EWS output and acting on it, except when they take way too long. You can have an idea of what the life of an EWS bot looks like by looking at the recent status for the WebKitGTK+ bots.

Maintaining all of those bots is at times a rather daunting task. The tests require a very specific set of packages, fonts, themes and icons to always report the same size for objects in a render. Upgrades, for instance, had to be synchronized, and usually involve generating new baselines for a large number of tests. You can see in these instructions, for instance, how strict the environment requirements are – yes, we need specific versions of fonts, because they often cause layouts to change in size! At one point we had tests fail after a compiler upgrade, which made rounding act a bit different!

So stability was a very important aspect of maintaining these bots. All of them have the same version of Debian, and most of the packages are pinned to the same version. On the other hand, and in direct contradition to the stability requirement, we often require bleeding edge versions of some libraries we rely on, such as libsoup. Since we started pushing WebKitGTK+ to be libsoup-only, its own progress has been pretty much driven by WebKitGTK+’s requirements, and Dan Winship has made it possible to make our soup backend much, much simpler and way more featureful. That meant, though, requiring very recent versions of soup.

To top it off, for anyone not running Debian testing and tracking the exact same versions of packages as the bots it was virtually impossible to get the tests to pass, which made it very difficult for even ourselves to make sure all patches were still passing before committing something. Wow, what a mess.

The explosion^Wsolution

So a few weeks back Martin Robinson came up with a proposed solution, which, as he says, is the “nuclear bomb” solution. We would have a jhbuild environment which would build and install all of the dependencies necessary for reproducing the test expectations the bots have. So over the first three days of the hackfest Martin and myself hacked away in building scripts, buildmaster integration, a jhbuild configuration, a jhbuild modules file, setting up tarballs, and wiring it all in a way that makes it convenient for the contributors to get along with. You’ll notice that our buildslaves now have a step just before compiling called “updated gtk dependencies” (gtk is the name we use for our port in the context of WebKit), which runs jhbuild to install any new dependencies or version bumps we added. You can also see that those instructions I mentioned above became a tad simpler.

It took us way more time than we thought for the dust to settle, but it eventually began to. The great thing of doing it during the hackfest was that we could find and fix issues with weird configurations on the spot! Oh, you build with AR_FLAGS=cruT and something doesn’t like it? OK, we fix it so that the jhbuild modules are not affected by that variable. Oh, turns out we missed a dependency, no problem, we add it to the modules file or install them on the bots, and then document the dependency. I set up a very clean chroot which we could use for trying out changes so as to not disrupt the tree too much for the other hackfest participants, and I think overall we did good.

The aftermath

By the time we were done our colleagues who ran other distributions such as Fedora were already being able to get a substantial improvements to the number of tests passing, and so did we! Also, the ability to seamlessly upgrade all the bots with a simple commit made it possible for us to very easily land a change that required a very recent (as in unreleased) version of soup which made our networking backend way simpler. All that red looks great, doesn’t it? And we aren’t done yet, we’ll certainly be making more tweaks to this infrastructure to make it more transparent and more helpful to the users (contributors and other people interested in running the tests).

If you’ve been hit by the instability we caused, sorry about that, poke mrobinson or myself in the #webkitgtk+ IRC channel on FreeNode, and we’ll help you out or fix any issues. If you haven’t, we hope you enjoy all the goodness that a reproducible testing suite has to offer! That’s it for now, folks, I’ll have more to report on follow-up work started at the hackfest soon enough, hopefully =).

By kov at December 07, 2011 11:34 PM

November 29, 2011

Accelerated Compositing in webkit-clutter

Gustavo Noronha

For a while now my fellow Collaboran Joone Hur has been working on implementing the Accelerated Compositing infrastructure available in WebKit in webkit-clutter, so that we can use Clutter’s powers for compositing separate layers and perform animations. This work is being done by Collabora and is sponsored by BOSCH, whom I’d like to thank! What does all this mean, you ask? Let me tell me a bit about it.

The way animations usually work in WebKit is by repainting parts of the page every few milliseconds. What that means in technical terms is that an area of the page gets invalidated, and since the whole page is one big image, all of the pieces that are in that part of the page have to be repainted: the background, any divs, images, text that are at that part of the page.

What the accelerated compositing code paths allow is the creation of separate pieces to represent some of the layers, allowing the composition to happen on the GPU, removing the need to perform lots of cairo paint operations per second in many cases. So if we have a semi-transparent video moving around the page, we can have that video be a separate texture that is layered on top of the page, made transparent and animated by the GPU. In webkit-clutter’s case this is done by having separate actors for each of the layers.

I have been looking at this code on and off, and recently joined Joone in the implementation of some of the pieces. The accelerated compositing infrastructure was originally built by Apple and is, for that reason, works in a way that is very similar to Core Animation. The code is still a bit over the place as we work on figuring out how to best translate the concepts into clutter concepts and there are several bugs, but some cool demos are already possible! Bellow you have one of the CSS3 demos that were made by Apple to demo this new functionality running on our MxLauncher test browser.

You can also see that the non-Accelerated version is unable to represent the 3D space correctly. Also, can you guess which of the two MxLauncher instances is spending less CPU? ;) In this second video I show the debug borders being painted around the actors that were created to represent layers.

The code, should you like to peek or test is available in the ac2 branch of our webkit-clutter repository: http://gitorious.org/webkit-clutter/webkit-clutter/commits/ac2

We still have plenty of work to do, so expect to hear more about it. During our annual hackfest in A Coruña we plan to discuss how this work could be integrated also in the WebKitGTK+ port, perhaps by taking advantage of clutter-gtk, which would benefit both ports, by sharing code and maintenance, and providing this great functionality to Epiphany users. Stay tuned!

By kov at November 29, 2011 05:55 PM

October 09, 2011

Tests Active

Brent Fulgham


Looking back over this blog, I see that it was around a year ago that I got the initial WinCairo buildbot running. I'm very pleased to announce that I have gotten ahold of a much more powerful machine, and am now able to run a full build and tests in slightly under an hour -- a huge improvement over the old hardware which took over two hours just to build the software!

This is a big step, because we can now track regressions and gauge correctness compared to the other platforms. Up to now, testing has largely consisted of periodic manual runs of the test suite, and a separate set of high-level tests run as part of a larger application. This was not ideal, because it was easy for low-level functions in WebKit that I rarely use to be broken and missed.

All is not perfect, of course. Although over 12,000 tests now run (successfully) with each build, that is effectively two thirds of the full test suite. Most of the tests I have disabled are due to small differences in the output layout. I'm trying to understand why these differences exist, but I suspect many of them simply reflect small differences in Cairo compared to the CoreGraphics rendering layer.

If any of you lurkers are interested in helping out, trying out some of the tests I have disabled and figuring out why they fail would be a huge help!

By Brent Fulgham (noreply@blogger.com) at October 09, 2011 02:43 AM

July 14, 2011

An Unseasonable Snowfall

Brent Fulgham

A year or two ago I ported the Cocoa "CallJS" application to MFC for use with WebKit. The only feedback I ever got on the topic was a complaint that it would not build under the Visual Studio Express software many people used.

After seeing another few requests on the webkit-help mailing list for information on calling JavaScript from C++ (and vice-versa), I decided to dust off the old program and convert it to pure WINAPI calls so that VS Express would work with it.

Since my beloved Layered Window patches finally landed in WebKit, I also incorporated a transparent WebKit view floating over the main application window. Because I suck at art, I stole appropriated the Let It Snow animation example to give the transparent layer something to do.

Want to see what it looks like?

By Brent Fulgham (noreply@blogger.com) at July 14, 2011 06:34 PM

July 10, 2011

Updated WebKit SDK (@r89864)

Brent Fulgham

I have updated the WebKitSDK to correspond to SVN revision r8984.

Major changes in this revision:
* JavaScript engine improvements.
* Rendering improvements.
* New 'Transparent Web View' support.
* General performance and memory use improvements.

This ZIP file also contains updated versions of Zlib, OpenSSL, cURL, and OpenCFLite.

Note that I have stopped statically linking Cairo; I'm starting to integrate some more recent Cairo updates (working towards some new rendering features), and wanted to be able to update it incrementally as changes are made.

This package contains the same Cairo library (in DLL form) as used in previous versions.

As usual, please let me know if you encounter any problems with this build.

[Update] I forgot to include zlib1.dll! Fixed in the revised zip file.

By Brent Fulgham (noreply@blogger.com) at July 10, 2011 04:24 AM

July 05, 2011

WinCairoRequirements Sources Archive

Brent Fulgham

I've posted the 80 MB source archive of the requirements needed to build the WinCairo port of WebKit.

Note that you do NOT need these sources unless you plan on building them yourself or wish to archive the source code for these modules. The binaries are always present in the WinCairoRequirements.zip file, which is downloaded and unzipped to the proper place when you execute the update-webkit --wincairo command.

By Brent Fulgham (noreply@blogger.com) at July 05, 2011 07:39 PM

June 28, 2011

Towards a Simpler WinCairo Build

Brent Fulgham


For the past couple of years, anyone interested in trying to build the WinCairo port of WebKit had to track down a number of support libraries, place them in their development environment's include (and link search) paths, and then cross their fingers and hope everything built.

To make things a little easier, I wrapped up the libraries and headers I use for building and posted them as a zip file on my .Mac account. This made things a little easier, but you still had to figure out where to drop the files and figure out if I had secretly updated my 'requirements.zip' file without telling anyone. Not ideal.

A couple of days ago, while trolling through the open review queue, I ran across a Bug filed by Carl Lobo, which automated the task of downloading the requirements file when running build-webkit --wincairo. This was a huge improvement!

Today, I hijacked Carl's changes and railroaded the patch through the review process (making a few modifications along the way):

  • I renamed my requirements file WinCairoRequirements.zip.

  • I added a timestamp file, so that build-webkit --wincairo can check to see if the file changed, and download it if necessary.

  • I propagated Carl's changes to update-webkit, so that now by adding the --wincairo argument it will update the WinCairoRequirements file.


I'm really excited about this update. If you've been wanting to try out the WinCairo port of WebKit, this would be a great time to try it out. I'd love to hear your experiences!

By Brent Fulgham (noreply@blogger.com) at June 28, 2011 04:42 AM

June 14, 2011

Benchmarking Javascript engines for EFL

Lucas De Marchi

The Enlightenment Foundation Libraries has several bindings for other languages in order to ease the creation of end-user applications, speeding up its development. Among them, there’s a binding for Javascript using the Spidermonkey engine. The questions are: is it fast enough? Does it slowdown your application? Is Spidermonkey the best JS engine to be used?

To answer these questions Gustavo Barbieri created some C, JS and Python benchmarks to compare the performance of EFL using each of these languages. The JS benchmarks were using Spidermonkey as the engine since elixir was already done for EFL. I then created new engines (with only the necessary functions) to also compare to other well-known JS engines: V8 from Google and JSC (or nitro) from WebKit.

Libraries setup

For all benchmarks EFL revision 58186 was used. Following the setup of each engine:

  • Spidermonkey: I’ve used version 1.8.1-rc1 with the already available bindings on EFL repository, elixir;
  • V8: version 3.2.5.1, using a simple binding I created for EFL. I named this binding ev8;
  • JSC: WebKit’s sources are needed to compile JSC. I’ve used revision 83063. Compiling with CMake, I chose the EFL port and enabled the option SHARED_CORE in order to have a separated library for Javascript;

Benchmarks

Startup time: This benchmark measures the startup time by executing a simple application that imports evas, ecore, ecore-evas and edje, bring in some symbols and then iterates the main loop once before exiting. I measured the startup time for both hot and cold cache cases. In the former the application is executed several times in sequence and the latter includes a call to drop all caches so we have to load the library again from disk

Runtime – Stress: This benchmark executes as many frames per second as possible of a render-intensive operation. The application is not so heavy, but it does some loops, math and interacts with EFL. Usually a common application would do far less operations every frame because many operations are done in EFL itself, in C, such as list scrolling that is done entirely in elm_genlist. This benchmark is made of 4 phases:

  • Phase 0 (P0): Un-scaled blend of the same image 16 times;
  • Phase 1 (P1): Same as P0, with additional 50% alpha;
  • Phase 2 (P2): Same as P0, with additional red coloring;
  • Phase 3 (P3): Same as P0, with additional 50% alpha and red coloring;

The C and Elixir’s versions are available at EFL repository.

Runtime – animation: usually an application doesn’t need “as many FPS as possible”, but instead it would like to limit to a certain amount of frames per second. E.g.: iphone’s browser tries to keep a constant of 60 FPS. This is the value I used on this benchmark. The same application as the previous benchmark is executed, but it tries to keep always the same frame-rate.

Results

The first computer I used to test these benchmarks on was my laptop. It’s a Dell Vostro 1320, Intel Core 2 Duo with 4 GB of RAM and a standard 5400 RPM disk. The results are below.

Benchmarks on Dell 1320 laptop

First thing to notice is there are no results for “Runtime – animation” benchmark. This is because all the engines kept a constant of 60fps and hence there were no interesting results to show. The first benchmark shows that V8’s startup time is the shortest one when considering we have to load the application and libraries from disk. JSC was the slowest and  Spidermonkey was in between.

With hot caches, however, we have another complete different scenario, with JSC being almost as fast as the native C application. Following, V8 with a delay a bit larger and Spidermonkey as the slowest one.

The runtime-stress benchmark shows that all the engines are performing well when there’s some considerable load in the application, i.e. removing P0 from from this scenario. JSC was always at the same speed of native code; Spidermonkey and V8 had an impact only when considering P0 alone.

 

Next computer to consider in order to execute these benchmarks was  a Pandaboard, so we can see how well the engines are performing in an embedded platform. Pandaboard has an ARM Cortex-A9 processor with 1GB of RAM and the partition containing the benchmarks is in an external flash storage drive. Following the results for each benchmark:

 

Benchmarks on Pandaboard

Once again, runtime-animation is not shown since it had the same results for all engines. For the startup tests, now Spidermonkey was much faster than the others, followed by V8 and JSC in both hot and cold caches. In runtime-stress benchmark, all the engines performed well, as in the first computer, but now JSC was the clear winner.

 

There are several points to be considered when choosing an engine to be use as a binding for a library such as EFL. The raw performance and startup time seems to be very near to the ones achieved with native code. Recently there were some discussions in EFL mailing list regarding which engine to choose, so I think it would be good to share these numbers above. It’s also important to notice that these bindings have a similar approach of elixir, mapping each function call in Javascript to the correspondent native function. I made this to be fair in the comparison among them, but depending on the use-case it’d  be good to have a JS binding similar to what python’s did, embedding the function call in real python objects.

By Lucas De Marchi at June 14, 2011 05:25 PM

April 29, 2011

Collection of WebKit ports

Holger Freyther

WebKit is a very successfull project. It is that in many ways. The code produced seems to very fast, the code is nice to work on, the people are great, the partys involved collaborate with each other in the interest of the project. The project is also very successfull in the mobile/smartphone space. All the major smartphone platforms but Windows7 are using WebKit. This all looks great, a big success but there is one thing that stands out.

From all the smartphone platforms no one has fully upstreamed their port. There might be many reasons for that and I think the most commonly heard reason is the time needed to get it upstreamed. It is specially difficult in a field that is moving as fast as the mobile industry. And then again there is absolutely no legal obligation to work upstream.

For most of today I collected the ports I am aware of, put them into one git repository, maybe find the point where they were branched, rebase their changes. The goal is to make it more easy to find interesting things and move them back to upstream. One can find the combined git tree with the tags here. I started with WebOS, moved to iOS, then to Bada and stopped at Android as I would have to pick the sourcecode for each android release for each phone from each vendor. I think I will just be happy with the Android git tree for now. At this point I would like to share some of my observations in the order I did the import.

Palm


Palm's release process is manual. In the last two releases they call the file .tgz but forgot to gzip it, in 2.0.0 the tarball name was in camel case. The thing that is very nice about Palm is that they provide their base and their changes (patch) separately. From looking at the 2.1.0 release it looks that for the Desktop version they want to implement Complex Font rendering. Earlier versions (maybe it is still the case) lack the support for animated GIF.

iOS


Apple's release process seems to be very structured. The source can be downloaded here. What I think is to note is that the release tarball contains some implementations of WebCore only as .o file and Apple has stopped releasing the WebKit sourcecode beginning with iOS 4.3.0.

Bada


This port is probably not known by many. The release process seems to be manual as well, the name of directories changed a lot between the releases, they come with a WML Script engine and they do ship something they should not ship.

I really hope that this combined tree is useful for porters that want to see the tricks used in the various ports and don't want to spend the time looking for each port separately.

By zecke (noreply@blogger.com) at April 29, 2011 07:20 PM

February 13, 2011

How to make the GNU Smalltalk Interpreter slower

Holger Freyther

This is another post about a modern Linux based performance measurement utility. It is called perf, it is included in the Linux kernel sources and it entered the kernel in v2.6.31-rc1. In many ways it is obsoleting OProfile, in fact for many architectures oprofile is just a wrapper around the perf support in the kernel. perf comes with a few nice application. perf top provides a statistics about which symbols in user and in kernel space are called, perf record to record an application or to start an application to record it and then perf report to browse this report with a very simple CLI utility. There are tools to bundle the record and the application in an archive, a diff utility.

For the last year I was playing a lot with GNU Smalltalk and someone posted the results of a very simplistic VM benchmark ran across many different Smalltalk implementations. In one of the benchmarks GNU Smalltalk is scoring last among the interpreters and I wanted to understand why it is slower. In many cases the JavaScriptCore interpreter is a lot like the GNU Smalltalk one, a simple direct-threaded bytecode interpreter, uses computed goto (even is compiled with -fno-gcse as indicated by the online help, not that it changed something for JSC), heavily inlined many functions.

There are also some differences, the GNU Smalltalk implementation is a lot older and in C. The first notable is that it is a Stack Machine and not register based, there are global pointers for the SP and the IP. Some magic to make sure that in the hot loop the IP/SP is 'local' in a register, depending on the available registers also keep the current argument in one, the interpreter definition is in a special file format but mostly similar to how Interepreter::privateExecute is looking like. The global state mostly comes from the fact that it needs to support switching processes and there might be some event during the run that requires access to the IP to store it to resume the old process. But in general the implementation is already optimized and there is little low hanging fruits and most experiments result in a slow down.

The two important things are again: Having a stable benchmark, having a tool to help to know where to look for things. In my case the important tools are perf stat, perf record, perf report and perf annotate. I have put a copy of the output to the end of this blog post. The stat utility provides one with number of instructions executed, branches, branch misses (e.g. badly predicted), L1/L2 cache hits and cache misses.

The stable benchmark helps me to judge if a change is good, bad or neutral for performance within the margin of error of the test. E.g. if I attempt to reduce the code size the instructions executed should decrease, if I start putting __builtin_expect.. into my code the number of branch misses should go down as well. The other useful utility is to the perf report that allows one to browse the recorded data, this can help to identify the methods one wants to start to optimize, it allows to annotate these functions inside the simple TUI interface, but does not support searching in it.

Because the codebase is already highly optimized any of my attempts should either decrease the code size (and the pressure on the i-cache), the data size (d-cache), remove stores or loads from memory (e.g. reorder instructions), fix branch predictions. The sad truth is that most of my changes were either slow downs or neutral to the performance and it is really important to undo these changes and not have false pride (unless it was also a code cleanup or such).

So after about 14 hours of toying with it the speed ups I have managed to make come from inlining a method to unwind a context (callframe), reordering some compares on the GC path and disabling the __builtin_expect branch hints as they were mostly wrong (something the kernel people found to be true in 2010 as well). I will just try harder, or try to work on the optimizer or attempt something more radical...



$ perf stat gst -f Bench.st
219037433 bytecodes/sec; 6025895 sends/sec

Performance counter stats for 'gst -f Bench.st':

17280.101683 task-clock-msecs # 0.969 CPUs
2076 context-switches # 0.000 M/sec
123 CPU-migrations # 0.000 M/sec
3925 page-faults # 0.000 M/sec
22215005506 cycles # 1285.583 M/sec (scaled from 70.02%)
40593277297 instructions # 1.827 IPC (scaled from 80.00%)
5063469832 branches # 293.023 M/sec (scaled from 79.98%)
70691940 branch-misses # 1.396 % (scaled from 79.98%)
27844326 cache-references # 1.611 M/sec (scaled from 20.02%)
134229 cache-misses # 0.008 M/sec (scaled from 20.03%)

17.838888599 seconds time elapsed


PS: The perf support probably works best on Intel based platforms and the biggest other problem is that perf annotate has some issues when the code is included from other c files.

By zecke (noreply@blogger.com) at February 13, 2011 08:56 PM

January 17, 2011

Using systemtap userspace tracing...

Holger Freyther

At the 27C3 we were running a GSM network and during the preparation I noticed a strange performance problem coming from the database library we are using running. I filled our database with some dummy data and created a file with the queries we normally run and executed time cat queries | sqlite3 file as a mini benchmark. I also hacked this code into our main routine and ran it with time as well. For some reason the code running through the database library was five times slower.

I was a bit puzzled and I decided to use systemtap to explore this to build a hypothesis and to also have the tools to answer the hypothesis. I wanted to find out if if it is slow because our database library is doing some heavy work in the implementation, or because we execute a lot more queries behind the back. I was creating the below probe:


probe process("/usr/lib/libsqlite3.so.0.8.6").function("sqlite3_get_table")
{
a = user_string($zSql);
printf("sqlite3_get_table called '%s'\n", a);
}


This probe will be executed whenever the sqlite3_get_table function of the mentioned library will be called. The $zSql is a variable passed to the sqlite3_get_table function and contains the query to be executed. I am converting the pointer to a local variable and then can print it. Using this simple probe helped me to see which queries were executed by the database library and helped me to do an easy optimisation.

In general it could be very useful to build a set of probes (I think one calls set a tapset) that check for API misusage, e.g. calling functions with certain parameters where something else might be better. E.g. in Glib use truncate instead of assigning "" to the GString, or check for calls to QString::fromUtf16 coming from Qt code itself. On second thought this might be better as a GCC plugin, or both.

By zecke (noreply@blogger.com) at January 17, 2011 12:41 PM

December 17, 2010

In the name of performance

Holger Freyther

I tend to see people doing weird things and then claim that the change is improving performance. This can be re-ordering instructions to help the compiler, attempting to use multiple cores of your system, writing a memfill in assembly. On the one hand people can be right and the change is making things faster, on the other hand they could use assembly to make things look very complicated, justify their pay, and you might feel awkward to question if it is making any sense.

In the last couple of weeks I have stumbled on some of those things. For some reason I found this bug report about GLIBC changing the memcpy routine for SSE and breaking the flash plugin (because it uses memcpy in the wrong way). The breakage is justified that the new memcpy was optimized and is faster. As Linus points out with his benchmark the performance improvement is mostly just wishful thinking.

Another case was someone providing MIPS optimized pixman code to speed-up all drawing which turned out to be wishful thinking as well...

The conclusion is. If someone claims that things are faster with his patch. Do not simply trust him, make sure he refers to his benchmark, is providing numbers of before and after and maybe even try to run it yourself. If he can not provide this, you should wonder how he measured the speed-up! There should be no place for wishful thinking in benchmarking. This is one of the areas where Apple's WebKit team is constantly impressing me.

By zecke (noreply@blogger.com) at December 17, 2010 01:48 PM

December 16, 2010

Benchmarking QtWebKit-V8 on Linux

University of Szeged

For some time it has been possible to build and run QtWebKit on Linux using Google's V8 JavaScript engine instead of the default JavaScriptCore. I thought it would be good to see some numbers comparing the runtime performance of the two engines in the same environment and also measuring the performance of the browser bindings.

read more

By andras.becsi at December 16, 2010 01:04 PM

October 23, 2010

Easily embedding WebKit into your EFL application

Lucas De Marchi

This is the first of a series of posts that I’m planning to do using basic examples in EFL, the Enlightenment Foundation Libraries. You may have heard that EFL is reaching its 1.0 release. Instead of starting from the very beginning with the basic functions of these libraries, I decided to go the opposite way, showing the fun stuff that is possible to do. Since I’m also an WebKit developer, let’s put the best of both softwares together and have a basic window rendering a webpage.

Before starting off, just some remarks:

  1. I’m using here the basic EFL + WebKit-EFL (sometimes called ewebkit). Developing an EFL application can be much simpler, particularly if you use an additional library with pre-made widgets like Elementary. However, it’s good to know how the underlying stuff works, so I’m providing this example.
  2. This could have been the last post in a series when talking about EFL since it uses at least 3 libraries. Don’t be afraid if you don’t understand what a certain function is for or if you can’t get all EFL and WebKit running right now. Use the comment section below and I’ll make my best to help you.

Getting EFL and WebKit

In order to able to compile the example here, you will need to compile two libraries from source: EFL and WebKit. For both libraries, you can either get the last version from svn or use the last snapshots provided.

  • EFL:

Grab a snapshot from the download page. How to checkout the latest version from svn is detailed here, as well as some instructions on how to compile

  • WebKit-EFL:

A very detailed explanation on how to get WebKit-EFL up and running is available on trac. Recently, though, WebKit-EFL started to be released too. It’s not detailed in the wiki yet, but you can grab a snapshot instead of checking out from svn.

hellobrowser!

In the spirit of “hello world” examples, our goal here is to make a window showing a webpage rendered by WebKit. For the sake of simplicity, we will use a default start page and put a WebKit-EFL “widget” to cover the entire window. See below a screenshot:

hellobrowser - WebKit + EFL

The code for this example is available here. Pay attention to a comment in the beginning of this file that explains how to compile it:

gcc -o hellobrowser hellobrowser.c \
     -DEWK_DATADIR="\"$(pkg-config --variable=datadir ewebkit)\"" \
     $(pkg-config --cflags --libs ecore ecore-evas evas ewebkit)

The things worth noting here are the dependencies and a variable. We directly depend on ecore and evas from EFL and on WebKit. We define a variable, EWK_DATADIR, using pkg-config so our browser can use the default theme for web widgets defined in WebKit. Ecore handles events like mouse and keyboard inputs, timers etc whilst evas is the library responsible for drawing. In a later post I’ll detail them a bit more. For now, you can read more about them on their official site.

The main function is really simple. Let’s divide it by pieces:

    // Init all EFL stuff we use
    evas_init();
    ecore_init();
    ecore_evas_init();
    ewk_init();

Before you use a library from EFL, remember to initialize it. All of them use their own namespace, so it’s easy to know which library you have to initialize: for example, if you call a function starting by “ecore_”, you know you first have to call “ecore_init()”. The last initialization function is WebKit’s, which uses the “ewk_” namespace.

    window = ecore_evas_new(NULL, 0, 0, 800, 600, NULL);
    if (!window) {
        fprintf(stderr, "something went wrong... :(\n");
        return 1;
    }

Ecore-evas then is used to create a new window with size 800×600. The other options are not relevant for an introduction to the libraries and you can find its complete documentation here.

    // Get the canvas off just-created window
    evas = ecore_evas_get(window);

From the Ecore_Evas object we just created, we grab a pointer to the evas, which is the space in which we can draw, adding Evas_Objects. Basically an Evas_Object is an object that you draw somewhere, i.e. in the evas. We want to add only one object to our window, that is where WebKit you render the webpages. Then, we have to ask WebKit to create this object:

    // Add a View object into this canvas. A View object is where WebKit will
    // render stuff.
    browser = ewk_view_single_add(evas);

Below I demonstrate a few Evas’ functions that you use to manipulate any Evas_Object. Here we are manipulating the just create WebKit object, moving to the desired position, resizing to 780x580px and then telling Evas to show this object. Finally, we tell Evas to show the window we created too. This way we have a window with an WebKit object inside with a little border.

    // Make a 10px border, resize and show
    evas_object_move(browser, 10, 10);
    evas_object_resize(browser, 780, 580);
    evas_object_show(browser);
    ecore_evas_show(window);

We need to setup a bit more things before having a working application. The first one is to give focus to the Evas_Object we are interested on in order to receive keyboard events when opened. Then we connect a function that will be called when the window is closed, so we can properly exit our application.

    // Focus it so it will receive pressed keys
    evas_object_focus_set(browser, 1);
 
    // Add a callback so clicks on "X" on top of window will call
    // main_signal_exit() function
    ecore_event_handler_add(ECORE_EVENT_SIGNAL_EXIT, main_signal_exit, window);

After this, we are ready to show our application, so we start the mainloop. This function will only return when the application is closed:

    ecore_main_loop_begin();

The function called when the application is close, just tell Ecore to exit the mainloop, so the function above returns and the application can shutdown. See its implementation below:

static Eina_Bool
main_signal_exit(void *data, int ev_type, void *ev)
{
    ecore_evas_free(data);
    ecore_main_loop_quit();
    return EINA_TRUE;
}

Before the application exits, we shutdown all the libraries that were initialized, in the opposite order:

    // Destroy all the stuff we have used
    ewk_shutdown();
    ecore_evas_shutdown();
    ecore_shutdown();
    evas_shutdown();

This is a basic working browser, with which you can navigate through pages, but you don’t have an entry to set the current URL, nor “go back” and “go forward” buttons etc. All you have to do is start adding more Evas_Objects to your Evas and connect them to the object we just created. For a still basic example, but with more stuff implemented, refer to the EWebLauncher that we ship with the WebKit source code. You can see it in the “WebKitTools/EWebLauncher/” folder or online at webkit’s trac. Eve is another browser with a lot more features that uses Elementary in addition to EFL, WebKit. See a blog post about it with some nice pictures.

Now, let’s do something funny with our browser. With a bit more lines of code you can turn your browser upside down. Not really useful, but it’s funny. All you have to do is to rotate the Evas_Object WebKit is rendering on. This is implemented by the following function:

// Rotate an evas object by 180 degrees
static void
_rotate_obj(Evas_Object *obj)
{
    Evas_Map *map = evas_map_new(4);
 
    evas_map_util_points_populate_from_object(map, obj);
    evas_map_util_rotate(map, 180.0, 400, 300);
    evas_map_alpha_set(map, 0);
    evas_map_smooth_set(map, 1);
    evas_object_map_set(obj, map);
    evas_object_map_enable_set(obj, 1);
 
    evas_map_free(map);
}

See this screenshot below and  get the complete source code.

EFL + WebKit doing Politreco upside down

By Lucas De Marchi at October 23, 2010 09:53 PM

October 02, 2010

Deploying WebKit, common issues

Holger Freyther

From my exposure to people deploying QtWebKit or WebKit/GTK+ there are some things that re-appear and I would like to discuss these here.

  • Weird compile error in JavaScript?
  • It is failing in JavaScriptCore as it is the first that is built. It is most likely that the person that provided you with the toolchain has placed a config.h into it. There are some resolutions to it. One would be to remove the config.h from the toolchain (many things will break), or use -isystem instead of -I for system includes.
    The best way to find out if you suffer from this problem is to use -E instead of -c to only pre-process the code and see where the various includes are coming from. It is a strategy that is known to work very well.

  • No pages are loaded.
  • Most likely you do not have a DNS Server set, or no networking, or the system your board is connected to is not forwarding the data. Make sure you can ping a website that is supposed to work, e.g. ping www.yahoo.com, the next thing would be to use nc to execute a simple HTTP 1.1 get on the site and see if it is working. In most cases you simply lack networking connectivity.

  • HTTPS does not work
  • It might be either an issue with Qt or an issue with your system time. SSL Certificates at least have two dates (Expiration and Creation) and if your system time is after the Expiration or before the Creation you will have issues. The easiest thing is to add ntpd to your root filesystem to make sure to have the right time.

    The possible issue with Qt is a bit more complex. You can build Qt without OpenSSL support, you can make it link to OpenSSL or you can make it to dlopen OpenSSL at runtime. If SSL does not work it is most likely that you have either build it without SSL support, or with runtime support but have failed to install the OpenSSL library.

    Depending on your skills it might be best to go back to ./configure and make Qt link to OpenSSL to avoid the runtime issue. strings is a very good tool to find out if your libQtNetwork.so contains SSL support, together with using objdump -x and search for _NEEDED you will find out which config you have.

  • Local pages are not loaded
  • This is a pretty common issue for WebKit/GTK+. In WebKit/GTK+ we are using GIO for local files and to determine the filetype it is using the freedesktop.org shared-mime-info. Make sure you have that installed.

  • The page only displays blank
  • This is another issue that comes back from time to time. It only appears on WebKit/GTK+ with the DirectFB backend but sadly people never report back if and how they have solved it. You could make a difference and contribute back to the WebKit project.


    In general most of these issues can be avoided by using a pre-packaged Embedded Linux Distribution like Ångström (or even Debian). The biggest benefit of that approach is that someone else made sure that when you install WebKit, all dependencies will be installed as well and it will just work for your ARM/MIPS/PPC system. It will save you a lot of time.

    By zecke (noreply@blogger.com) at October 02, 2010 06:12 AM

    August 28, 2010

    WebKit

    Lucas De Marchi

    After some time working with the EFL port of WebKit, I’ve been nominated as an official webkit developer. Now I have super powers in the official repository :-), but I swear I intend to use it with caution and responsibility. I’ll not forget Uncle Ben’s advice: ”with great power comes great responsibility”.

    I’m preparing a post to talk about WebKit, EFL, eve (a new web browser based on WebKit + EFL) and how to easily embed a browser in your application. Stay tuned.

    By Lucas De Marchi at August 28, 2010 03:15 AM

    August 10, 2010

    Coscup2010/GNOME.Asia with strong web focus

    Holger Freyther

    On the following weekend the Coscup 2010/GNOME.Asia is taking place in Taipei. The organizers have decided to have a strong focus on the Web as can be seen in the program.

    On saturday there are is a keynote and various talks about HTML5, node.js. The Sunday will see three talks touching WebKit/GTK+. There is one about building a tablet OS with WebKit/GTK+, one by Xan Lopez on how to build hybrid applications (a topic I have devoted moiji-mobile.com to) and a talk by me using gdb to explain how WebKit/GTK+ is working and how the porting layer interacts with the rest of the code.

    I hope the audience will enjoy the presentations and I am looking forward to attend the conference, there is also a strong presence of the ex-Openmoko Taiwan Engineering team. See you on Saturday/Sunday and drop me an email if you want to talk about WebKit or GSM...

    By zecke (noreply@blogger.com) at August 10, 2010 04:32 PM

    July 16, 2010

    Cross-compiling QtWebKit for Windows on Linux using MinGW

    University of Szeged

    In this post I'll show you how to configure and compile a MinGW toolchain for cross-compilation on Linux, then how to build Qt using this toolchain and finally compile the Qt port of WebKit from trunk.

    read more

    By andras.becsi at July 16, 2010 09:31 AM

    September 06, 2008

    Skia graphics library in Chrome: First impressions

    Alp Toker

    With the release of the WebKit-based Chrome browser, Google also introduced a handful of new backends for the browser engine including a new HTTP stack and the Skia graphics library. Google’s Android WebKit code drops have previously featured Skia for rendering, though this is the first time the sources have been made freely available. The code is apparently derived from Google’s 2005 acquisition of North Carolina-based software firm Skia and is now provided under the Open Source Apache License 2.0.

    Weighing in at some 80,000 lines of code (to Cairo’s 90,000 as a ballpark reference) and written in C++, some of the differentiating features include:

    • Optimised software-based rasteriser (module sgl/)
    • Optional GL-based acceleration of certain graphics operations including shader support and textures (module gl/)
    • Animation capabilities (module animator/)
    • Some built-in SVG support (module (svg/)
    • Built-in image decoders: PNG, JPEG, GIF, BMP, WBMP, ICO (modules images/)
    • Text capabilities (no built-in support for complex scripts)
    • Some awareness of higher-level UI toolkit constructs (platform windows, platform events): Mac, Unix (sic. X11, incomplete), Windows, wxwidgets
    • Performace features
      • Copy-on-write for images and certain other data types
      • Extensive use of the stack, both internally and for API consumers to avoid needless allocations and memory fragmentation
      • Thread-safety to enable parallelisation

    The library is portable and has (optional) platform-specific backends:

    • Fonts: Android / Ascender, FreeType, Windows (GDI)
    • Threading: pthread, Windows
    • XML: expat, tinyxml
    • Android shared memory (ashmem) for inter-process image data references

    Skia Hello World

    In this simple example we draw a few rectangles to a memory-based image buffer. This also demonstrates how one might integrate with the platform graphics system to get something on screen, though in this case we’re using Cairo to save the resulting image to disk:

    #include "SkBitmap.h"
    #include "SkDevice.h"
    #include "SkPaint.h"
    #include "SkRect.h"
    #include <cairo.h>
     
    int main()
    {
      SkBitmap bitmap;
      bitmap.setConfig(SkBitmap::kARGB_8888_Config, 100, 100);
      bitmap.allocPixels();
      SkDevice device(bitmap);
      SkCanvas canvas(&device);
      SkPaint paint;
      SkRect r;
     
      paint.setARGB(255, 255, 255, 255);
      r.set(10, 10, 20, 20);
      canvas.drawRect(r, paint);
     
      paint.setARGB(255, 255, 0, 0);
      r.offset(5, 5);
      canvas.drawRect(r, paint);
     
      paint.setARGB(255, 0, 0, 255);
      r.offset(5, 5);
      canvas.drawRect(r, paint);
     
      {
        SkAutoLockPixels image_lock(bitmap);
        cairo_surface_t* surface = cairo_image_surface_create_for_data(
            (unsigned char*)bitmap.getPixels(), CAIRO_FORMAT_ARGB32,
            bitmap.width(), bitmap.height(), bitmap.rowBytes());
        cairo_surface_write_to_png(surface, "snapshot.png");
        cairo_surface_destroy(surface);
      }
     
      return 0;
    }

    You can build this example for yourself linking statically to the libskia.a object file generated during the Chrome build process on Linux.

    Not just for Google Chrome

    The Skia backend in WebKit, the first parts of which are already hitting SVN (r35852, r36074) isn’t limited to use in the Chrome/Windows configuration and some work has already been done to get it up and running on Linux/GTK+ as part of the ongoing porting effort.

    The post Skia graphics library in Chrome: First impressions appeared first on Alp Toker.

    By alp at September 06, 2008 12:11 AM

    June 12, 2008

    WebKit Meta: A new standard for in-game web content

    Alp Toker

    Over the last few months, our browser team at Nuanti Ltd. has been developing Meta, a brand new WebKit port suited to embedding in OpenGL and 3D applications. The work is being driven by Linden Lab, who are eagerly investigating WebKit for use in Second Life.

    While producing Meta we’ve paid great attention to resolving the technical and practical limitations encountered with other web content engines.


    uBrowser running with the WebKit Meta engine

    High performance, low resource usage

    Meta is built around WebKit, the same engine used in web browsers like Safari and Epiphany, and features some of the fastest content rendering around as well as nippy JavaScript execution with the state of the art SquirrelFish VM. The JavaScript SDK is available independently of the web renderer for sandboxed client-side game scripting and automation.

    It’s also highly scalable. Some applications may need only a single browser context but virtual worlds often need to support hundreds of web views or more, each with active content. To optimize for this use case, we’ve cut down resource usage to an absolute minimum and tuned performance across the board.

    Stable, easy to use cross-platform SDK

    Meta features a single, rock-solid API that works identically on all supported platforms including Windows, OS X and Linux. The SDK is tailored specifically to embedding and allows tight integration (shared main loop or operation in a separate rendering thread, for example) and hooks to permit seamless visual integration and extension. There is no global setup or initialization and the number of views can be adjusted dynamically to meet resource constraints.

    Minimal dependencies

    Meta doesn’t need to use a conventional UI toolkit and doesn’t need any access to the underlying windowing system or the user’s filesystem to do its job, so we’ve done away with these concepts almost entirely. It adds only a few megabytes to the overall redistributable application’s installed footprint and won’t interfere with any pre-installed web browsers on the user’s machine.

    Nuanti will be offering commercial and community support and is anticipating involvement from the gaming industry and homebrew programmers.

    In the mid term, we aim to submit components of Meta to the WebKit Open Source project, where our developers are already actively involved in maintaining various subsystems.

    Find out more

    Today we’re launching meta.nuanti.com and two mailing lists to get developers talking. We’re looking to make this site a focal point for embedders, choc-full of technical details, code samples and other resources.

    The post WebKit Meta: A new standard for in-game web content appeared first on Alp Toker.

    By alp at June 12, 2008 09:35 AM

    April 21, 2008

    Acid3 final touches

    Alp Toker

    Recently we’ve been working to finish off and land the last couple of fixes to get a perfect pixel-for-pixel match against the reference Acid3 rendering in WebKit/GTK+. I believe we’re the first project to achieve this on Linux — congratulations to everyone on the team!


    Epiphany using WebKit r32284

    We also recently announced our plans to align more closely with the GNOME desktop and mobile platform. To this end we’re making a few technology and organisational changes that I hope to discuss in an upcoming post.

    The post Acid3 final touches appeared first on Alp Toker.

    By alp at April 21, 2008 02:38 AM

    April 06, 2008

    WebKit Summer of Code Projects

    Alp Toker

    With the revised deadline for Google Summer of Code ’08 student applications looming, we’ve been getting a lot of interest in browser-related student projects. I’ve put together a list of some of my favourite ideas.

    If in doubt, now’s the time to submit proposals. Already-listed ideas are the most likely to get mentored but students are free to propose their own ideas as well. Proposals for incremental improvements will tend to be favoured over ideas for completely new applications, but a proof of concept and/or roadmap can help when submitting plans for larger projects.

    Update: There’s no need to keep asking about the status of an application on IRC/private mail etc. It’s a busy time for the upstream developers but they’ll get back in touch as soon as possible.

    The post WebKit Summer of Code Projects appeared first on Alp Toker.

    By alp at April 06, 2008 08:40 PM

    March 27, 2008

    WebKit gets 100% on Acid3

    Alp Toker

    Today we reached a milestone with WebKit/GTK+ as it became the first browser engine on Linux/X11 to get a full score on Acid3, shortly after the Acid3 pass by WebKit for Safari/Mac.

    Acid3
    Epiphany using WebKit r31371

    There is actually still a little work to be done before we can claim a flawless Acid3 pass. Two of the most visible remaining issues in the GTK+ port are :visited (causing the “LINKTEST FAILED” notice in the screenshot) and the lack of CSS text shadow support in the Cairo/text backend which is needed to match the reference rendering.

    It’s amazing to see how far we’ve come in the last few months, and great to see the WebKit GTK+ team now playing an active role in the direction of WebCore as WebKit continues to build momentum amongst developers.

    Update: We now also match the reference rendering.

    The post WebKit gets 100% on Acid3 appeared first on Alp Toker.

    By alp at March 27, 2008 09:06 PM

    March 15, 2008

    Bossa Conf ’08

    Alp Toker

    Am here in the LHR lounge. In a couple of hours, we take off for the INdT Bossa Conference, Pernambuco, Brazil via Lisbon. Bumped in to Pippin who will be presenting Clutter. Also looking forward to Lennart‘s PulseAudio talk amongst others.

    If you happen to be going, drop by on my WebKit Mobile presentation, 14:00 Room 01 this Monday. We have a small surprise waiting for Maemo developers.

    WebKit Mobile

    The post Bossa Conf ’08 appeared first on Alp Toker.

    By alp at March 15, 2008 03:29 AM