Created attachment 47243 [details] my render results - note destination-in and destination-atop Summary describes the problem. This exists in Safari 4.0.4 as well as nightlies, and I'm not sure about other possible versions, but it likely affects them all. In more detail, for searching & future reference: When a canvas' globalCompositeOperation is set to "destination-in" or "destination-atop", WebKit does not render correctly. Destination-in should retain the destination data where the new object overlaps, and the new object should not appear at all. Currently, the entire destination is retained, and the source does not appear. Destination-atop should retain the destination data where the new object overlaps, and the new object should appear where not covered by the destination. Currently, the destination is fully retained, and the new object appears to be drawn "under", though I cannot attest to what's actually being rendered. Expected render results: https://developer.mozilla.org/en/Canvas_tutorial%3aCompositing#globalCompositeOperation Final render results: https://developer.mozilla.org/samples/canvas-tutorial/6_1_canvas_composite.html My render results are attached.
Created attachment 47245 [details] Reduction Code is modified from the Mozilla website linked originally.
Created attachment 47246 [details] Correct render results Also from the Mozilla site, these are what should have rendered.
Noted that it has a reduction.
Merging this bug as Bug 39177 seems to be more generic. *** This bug has been marked as a duplicate of bug 39177 ***