On Mon, Jan 11, 2010 at 9:04 PM, Chris Evans <cev...@chromium.org> wrote:
> Hi,
> I found this interesting: http://a.qoid.us/google.html
> Because it's clearly very non-JavaScript focused (just a CSS rotation) and
> yet the browsers exhibit very different performance characteristics.
> All on my underpowered Windows laptop,
> Chrome 3 & 4: smooth. Very nice anti-aliased accurate rendering.
> Safari 4: not quite as smooth; less fps but still not bad. Text / lines more
> jagged and text "wobbles" during the rotation.
> The other browsers do not support the CSS used / required for this demo.
> There was a similar version, but using SVG animation to do something very
> similar. (It's currently offline). Firefox and Opera were able to attempt
> the rotation of this one but both performed much worse that Safari and
> Chrome.
> Anyone know why Chrome, and to a certain extent Safari, are so much better
> on this non-JS test? Is the Skia library underpinning Chrome superior?
> There's also a difference between Chrome Windows and Chrome Linux. Whilst
> Chrome Linux performs smoothly, the text is clearly jiggling around and even
> getting more / less bold throughout the rotation cycle. Doesn't do that on
> Windows. Any ideas?
I imagine the problems on Linux are the same as they were on Windows,
where the underlying graphics layer wants to place glyphs aligned on
pixel boundaries. This gives rounding problems and the letters jump
around. I spent several weeks making the rotations and transparency on
Windows text and form controls look good.
Brett
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