Issue 46021 - chromium - Incorrect rendering of compound paths in canvas - An open-source project to help move the web forward.

Issue 46021:	Incorrect rendering of compound paths in canvas
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Status:	Fixed
Owner:	----
Closed:	Aug 2012
Cc:	senorbla...@chromium.org
Type-Bug Pri-2 Cr-Blink Cr-Blink-Layout

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Reported by josh.f...@gmail.com, Jun 7, 2010

Chrome Version       : 6.0.422.0 dev on Linux
Other browsers tested:
Chrome 6.0.422.0 dev on Mac OS X: OK
     Safari 4: OK
  Firefox 3.x: OK
         IE 7: N/A
         IE 8: N/A

What steps will reproduce the problem?
var ctx = someCanvasElement.getContext('2d');
ctx.beginPath();
ctx.arc(100, 100, 50, 0, 2*Math.PI, false);
ctx.arc(100, 100, 40, 0, 2*Math.PI, true);
ctx.fillStyle = '#ff0000';
ctx.fill();

What is the expected result?
You should see a red 'donut'.

What happens instead?
A plain red circle is drawn.

Please provide any additional information below. Attach a screenshot if
possible.

Jun 7, 2010

#1 jamesr@chromium.org

Looks like a skia bug.

Status: Untriaged
Cc: senorbla...@chromium.org

Sep 29, 2010

#2 re...@nolten.nu

I ran into the same bug today on Chrome for Windows. Chrome on Mac appears to be OK, It's easy to create a workaround by using overlapping circles, but it would be nice if it is fixed.

I tried to circumvent the bug by adding lines like this:

ctx.arc(centerX, centerY, innerRadius, 0, Math.PI*2, false);
ctx.lineTo(centerX+innerRadius+diameter,centerY);
ctx.arc(centerX, centerY, innerRadius+diameter, Math.PI*2, 0,true);
ctx.lineTo(centerX+innerRadius,centerY);

But this obviously didn't help...

Mar 3, 2011

#3 steven.b...@gmail.com

i think this is actually a webkit bug.

in WebCore/platform/graphics/skia/PathSkia.cpp, in Path::addArc, if the arc in question is a full circle, it apparently just draws an oval and disregards anticlockwise.

i really can't believe this has been around for 8 months with no traction :(. this seems like a pretty bad bug.

Feb 16, 2012

#4 isherman@chromium.org

(No comment was entered for this change.)

Labels: -Area-Undefined Area-WebKit WebKit-Rendering

Aug 2, 2012

#5 senorbla...@chromium.org

Thanks for the report.  I couldn't reproduce this in r22.0.1221.1, and looks like it was fixed in http://trac.webkit.org/changeset/80409.  Closing as fixed.

Status: Fixed

Oct 13, 2012

#6 bugdroid1@chromium.org

This issue has been closed for some time. No one will pay attention to new comments.
If you are seeing this bug or have new data, please click New Issue to start a new bug.

Labels: Restrict-AddIssueComment-Commit

Mar 10, 2013

#7 bugdroid1@chromium.org

(No comment was entered for this change.)

Labels: -Area-WebKit -WebKit-Rendering Cr-Content-Rendering Cr-Content

Apr 5, 2013

#8 bugdroid1@chromium.org

(No comment was entered for this change.)

Labels: -Cr-Content Cr-Blink

Apr 5, 2013

#9 bugdroid1@chromium.org

(No comment was entered for this change.)

Labels: -Cr-Content-Rendering Cr-Blink-Rendering

Jan 9, 2015

#10 lafo...@google.com

Migrate from Cr-Blink-Rendering to Cr-Blink-Layout

Labels: -Cr-Blink-Rendering Cr-Blink-Layout

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