[webkit-dev] Switching away from integers for layout

[Robert O'Callahan]

On Fri, Jun 24, 2011 at 7:11 AM, Levi Weintraub <leviw at google.com> wrote:

> Emil and I looked into what Firefox did. They did go with a
> fixed-point-esque approach where one of their units represents 1/96th of a
> pixel. That number should tell you something about when this work was done,
> and they were mostly concerned about performance.


Back in the mists of time the units were variable and sometimes equal to
1/96 of a pixel. More recently (but still years ago) we changed to 1/60 of a
CSS pixel. And we chose fixed-point-esque not just because of performance
but also because you keep useful properties such as associativity and
commutativity.

If you're doing performance tests, make sure you test on ARM systems, which
have widely varying floating-point capabilities.

Rob
-- 
"If we claim to be without sin, we deceive ourselves and the truth is not in
us. If we confess our sins, he is faithful and just and will forgive us our
sins and purify us from all unrighteousness. If we claim we have not sinned,
we make him out to be a liar and his word is not in us." [1 John 1:8-10]
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