Bug 55380

Summary:

[Qt] HTML canvas arc circle shows aliasing on Symbian devices

Product:

WebKit

Reporter:

Fabrizio <fabrizio.machado>

Component:

Layout and Rendering

Assignee:

Nobody <webkit-unassigned>

Status:

RESOLVED WORKSFORME

Severity:

Minor

CC:

benjamin, cmarcelo, joel.parks

Priority:

Keywords:

EasyFix, Qt, QtTriaged

Version:

528+ (Nightly build)

Hardware:

All

OS:

All

Attachments:

Description	Flags
html canvas animation test case	none
Set render hint for HTML5 canvas img buffer to Antialiasing for Symbian platform	benjamin: review-

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-	Details Formatted Diff Diff
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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