RESOLVED WORKSFORME 55380
[Qt] HTML canvas arc circle shows aliasing on Symbian devices 
https://bugs.webkit.org/show_bug.cgi?id=55380
Summary [Qt] HTML canvas arc circle shows aliasing on Symbian devices
Fabrizio
Reported 2011-02-28 07:56:47 PST
Steps to reproduce: 1. Load Canvas_Spinner.htm in QtTestBrowser 2. In QtTestBrowser, zoom out until browser cannot zoom any further. Actual result: spinning circle animation shows white spots Expected result: spinning circle animation is smooth with no spots
Attachments
html canvas animation test case (2.01 KB, text/html)
2011-02-28 07:57 PST, Fabrizio 		no flags
Details
Set render hint for HTML5 canvas img buffer to Antialiasing for Symbian platform (16.37 KB, patch)
2011-03-21 06:42 PDT, Fabrizio 		benjamin: review-
DetailsFormatted DiffDiff
Show Obsolete (2) View All Add attachment proposed patch, testcase, etc.
Fabrizio
Comment 1 2011-02-28 07:57:18 PST
Created attachment 84061 [details] html canvas animation test case
Benjamin Poulain
Comment 2 2011-02-28 08:08:04 PST
My guess is it is just the interpolation function used over the canvas.
Fabrizio
Comment 3 2011-03-01 07:47:08 PST
While debugging test case, I saw that in GraphicsContext::setImageInterpolationQuality, we are setting the quality to InterpolationMedium, and thus hint painter to use SmoothPixmapTransform. I tried giving other hints to see what would happen, but it has no apparent effect on the appearance.
Fabrizio
Comment 4 2011-03-21 06:38:39 PDT
updated title to avoid creating a new report.
Fabrizio
Comment 5 2011-03-21 06:42:00 PDT
Created attachment 86316 [details] Set render hint for HTML5 canvas img buffer to Antialiasing for Symbian platform The originally attached animation test also fails badly on symbian and is addressed with this patch. The layout test in the patch is a simplified version of another test case also affected by the bug.
Benjamin Poulain
Comment 6 2011-03-21 07:51:06 PDT
Comment on attachment 86316 [details] Set render hint for HTML5 canvas img buffer to Antialiasing for Symbian platform My comments: -you should do a proper fix, not just quick hack -why would that be Symbian specific? -you have a symbian specific change, add layout test results for pixel test, while layout tests do not run on Symbian, what am I missing here? -there is seriously no existing test that could cover that case?
Fabrizio
Comment 7 2011-03-22 04:38:53 PDT
Based on offline discussions, this bug can be closed, since the less "hack-y" fix already exists here in trunk in GraphicsContextPlatformPrivate constructor.
Benjamin Poulain
Comment 8 2011-03-22 05:31:25 PDT
(In reply to comment #7) > Based on offline discussions, this bug can be closed, since the less "hack-y" fix already exists here in trunk in GraphicsContextPlatformPrivate constructor.
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