Bug 36226 - [Qt] canvas arc element doesn't render correctly
Summary: [Qt] canvas arc element doesn't render correctly
Status: RESOLVED FIXED
Alias: None
Product: WebKit
Classification: Unclassified
Component: Layout and Rendering (show other bugs)
Version: 528+ (Nightly build)
Hardware: PC Linux
: P2 Normal
Assignee: Nobody
URL:
Keywords: HTML5
Depends on:
Blocks:
 
Reported: 2010-03-17 10:00 PDT by lonhutt
Modified: 2010-08-16 17:13 PDT (History)
3 users (show)

See Also:


Attachments
html file that describes 2 canvas arc shapes (1017 bytes, text/html)
2010-03-17 13:46 PDT, lonhutt
no flags Details

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Description lonhutt 2010-03-17 10:00:17 PDT
the endpoint of a canvas arc element renders with a jagged edge at the start point.

the easiest way i've found to see the effect is to install the Arora web browser and view the attached HTML file. Alternatively create a simple Qt web browser that points at the provided HTML file.

I have been unable to reproduce this error in any other WebKit based browser (tested Chrome, Safari, Konqueror) which makes me think it must be a Qt specific bug.
Comment 1 lonhutt 2010-03-17 13:46:35 PDT
Created attachment 50952 [details]
html file that describes 2 canvas arc shapes
Comment 2 Dirk Schulze 2010-03-26 03:22:32 PDT
This is a Qt-bug. If you create a new path, the starting point is set to 0,0. A workaround is setting moveTo after beginning a new path.
Comment 3 lonhutt 2010-04-08 12:24:18 PDT
I changed:

ctx.beginPath();
ctx.lineWidth = 8;
ctx.strokeStyle = "#33CCCC";
ctx.arc(342, 212, 56.25714285714286, 6.997183637540902, 7.5683823018299545, false);
ctx.stroke();
ctx.closePath();

to:

ctx.beginPath();
ctx.moveTo(342, 212);
ctx.lineWidth = 8;
ctx.strokeStyle = "#33CCCC";
ctx.arc(342, 212, 56.25714285714286, 6.997183637540902, 7.5683823018299545, false);
ctx.stroke();
ctx.closePath();

with no results. What am I doing wrong?
Comment 4 Andreas Kling 2010-05-04 18:46:00 PDT
@Dirk: I think you guys are talking about two separate issues :)
I've posted a patch for yours at https://bugs.webkit.org/show_bug.cgi?id=38526

@lonhutt: Jagged edge confirmed on ToT, will investigate.
Comment 5 Andreas Kling 2010-08-16 17:13:03 PDT
This was indeed fixed with http://trac.webkit.org/changeset/59767