Created attachment 132612 [details]
Expected behaviour, as tested in Firefox 10, IE 10, Opera 11
When a stroke is applied to a canvas with the globalCompositeOperation set to:
The composition does not occur as expected, with the destination image still visible where it should not be.
Reference rendering from Mozilla Firefox 10: http://i.imgur.com/zoQsB.png (Identical to IE 10 & Opera 11)
Webkit rendering: http://i.imgur.com/NiNpO.png
jsFiddle testing stroke composition for each globalCompositeOperation: http://jsfiddle.net/dH7KW/
Created attachment 132613 [details]
Incorrect Rendering in Webkit
I forgot to mention in the original report, this is fairly easy to work around. Just create a new Canvas element, apply the stroke to it, then draw that canvas to the destination using drawImage() with the desired globalCompositeOperation set.
Duplicate of bug 66762, missed this the first time I searched.
*** This bug has been marked as a duplicate of bug 66762 ***