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June 15, 2005

Win32 Backend Renderer

I'm considering switching the renderer that Mozilla SVG uses on win32 to cairo from GDI+. The reasons for this:

There is one missing chunk of functionality in the existing cairo 0.5.0 win32 backend, the ability to convert text to paths. I've implemented this and have asked the cairo people for review.

One problem we're currently seeing with cairo is incorrect blending results when compiling with Visual C 6.0 optimized and on OS-X (bug 293353).

Some timing results of cairo vs. GDI+ for Hixie's simple SVG performance tests - time in seconds:

cairo gdi+
test1 25.8 15.7
test2 25.5 15.9
test3 5.3 5.3
test4 126.3 6.5

As you can see, the numbers aren't that bad except for test4, where cairo is about nineteen times slower than GDI+. This test renders a large number of <svg:image>s. While I haven't been able to get a profile on Win32 (any Quantify experts, please speak up), this test runs equally slow on linux and a profile there shows the majority of the time is spent here: 

samples  %        symbol name
1996617  57.9397  PictureTransformPoint
961417   27.8993  __divdi3
474326   13.7644  miPointInRegion

PictureTranformPoint is shared code with libpixman (called pixman_transform_point), called by the general compositing function. Talking to the cairo people, there have been some changes in the freedesktop.org xserver tree to speed this up, which haven't made it back to libpixman yet.

Posted by tor at 12:04 AM | Comments (11)

June 14, 2005

2005-06-14 Update

Checkins during the past two weeks: Patches lurking:

Posted by tor at 11:02 PM

June 1, 2005

2005-06-01 Weekly Update

Checkins during the past two and a half weeks: Patches lurking:

Posted by tor at 10:22 PM

Call for opinion: <foreignObject> in Firefox 1.1

In the recently released Firefox 1.1a1 there is a restricted implementation of SVG's <foreignObject> element. It can only do translations, not guaranteed "live" with respect to its contents, and behavior with respect to z-ordering and clipping is undefined.

Some people think that this rudimentary <foreignObject> should be removed for Firefox 1.1 because content written for a future full implementation of the feature will fail ungracefully on Firefox 1.1. Are any content developers out there working on content that uses the existing <foreignObject> and would be disappointed in it being removed until the next major version of Firefox after 1.1?

Posted by tor at 7:33 PM | Comments (23)

Call for opinion: text-zoom interaction with SVG

Currently the browser text-zoom value causes a corresponding increase/decrease in the size of SVG text. We have a patch that would change that behavior (bug 291785), but there is a thought that for consistency all fonts on the page should change with text-zoom. In the future when text-zoom is replaced with page-zoom, the SVG area will be also increased proportionally in size.

Posted by tor at 7:19 PM | Comments (25)