770571 - <canvas> box loses anti-aliasing after calling getContext('2d')

Status: RESOLVED WORKSFORME

(Core :: Graphics: Layers, defect)

Description

[g.underflow]

Attachment: canvas-border-alias-reproduce.html

User Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:13.0) Gecko/20100101 Firefox/13.0.1
Build ID: 20120614114901

Steps to reproduce:

Use css border on <canvas> element, apply "-moz-transform: rotate(25deg)" or any other angle. The border of rotated <canvas> element is anti-aliased like any other element. Now in javascript get the reference to this <canvas> element and call getContext('2d') on it. 


Actual results:

After calling getContext <canvas> element's border becomes jagged and not anti-aliased


Expected results:

The border should have remained anti-aliased (the border remains anti-aliased and smoothed in all the rest of major browsers like Chrome, Safari, IE9)

Comment 1

[g.underflow]

Setting layers.acceleration.disabled to true fixes this and border of the element is no more jagged. However it is jagged with layers acceleration enabled.

Comment 2

[u279076]

Did this regress at some point? Can you try some previous Firefox versions to see if it reproduces? Our nightlies can be found on ftp.mozilla.org.

Comment 3

[g.underflow]

The problem exists in both FF4 and latest nightly FF16a1. Again, setting layers.acceleration.disabled to true fixes the aliased border on both versions. Since, as I understand, layers.acceleration was introduced in FF4 that means that the problem started there and still exists.

Comment 4

[g.underflow]

So when will this get confirmed? It's not that hard to confirm, Win7, any version of Firefox4+, and layers acceleration enabled.

Comment 5

[u279076]

It will be confirmed as soon as someone else can confirm it. I don't have access to layers capable hardware at this time.

Comment 6

[g.underflow]

So what? No one in the entire Mozilla has layers capable hardware? The bug still persists.

Comment 7

[u279076]

Attachment: testcase

Thanks for commenting. This reminded me to check back on this bug. Since I last commented I've acquired a machine capable of layers acceleration. I apologize that this slipped through my purview. I've updated your testcase to show the comparison. It's quite easy to reproduce this bug. Marking as NEW.

Comment 8

[Gregory Pappas [:gregp]]

Unable to reproduce