RESOLVED FIXED51609
Accumulated pixel rounding of 'left' results in jumps when transitioning it 
https://bugs.webkit.org/show_bug.cgi?id=51609
Summary Accumulated pixel rounding of 'left' results in jumps when transitioning it
Vincent Meurisse
Reported 2010-12-25 10:53:10 PST
Created attachment 77438 [details] Testcase When combining CSS transitions (eg. an animated div inside another animated div), I expect the resulting animation to be smooth. Instead, each position is rounded to the closest pixel before the final sum. Please look at the attachment for a demo (and open it in Firefox4 for the expected result). Please note that using floating point arithmetic for calulation would solve both this bug and #15827 as the lack of synchronization will then result in less than 1px of error.
Attachments
Testcase (1.04 KB, text/html)
2010-12-25 10:53 PST, Vincent Meurisse 		no flags
Details
View All Add attachment proposed patch, testcase, etc.
Luke Macpherson
Comment 1 2011-10-05 20:57:10 PDT
Levi & Emil, do you think this will be fixed by the switch to floating point everywhere that you guys are working on?
Emil A Eklund
Comment 2 2011-10-06 08:36:12 PDT
Yeah, seems likely. I'll try the attached test case on our build and report back.
Emil A Eklund
Comment 3 2011-10-06 11:29:19 PDT
Turns it it's still failing when running our patched browser with sub-pixel precision. From looking at the test case the desired behavior isn't obvious. I assume you expect the divs to snap one at a time resulting in a smoother transition?
Levi Weintraub
Comment 4 2011-10-06 11:46:31 PDT
Yeah, you can see the proper expected results in FFX7. This should be solvable with our patch, but unfortunately still seems to a problem at the moment.
Emil A Eklund
Comment 5 2012-10-08 16:11:44 PDT
The attached test case now works as expected with SUBPIXEL_LAYOUT enabled.
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