[Webkit-unassigned] [Bug 34027] New: Canvas globalCompositeOperation does not render destination-in or destination-atop correctly

[bugzilla-daemon at webkit.org]

https://bugs.webkit.org/show_bug.cgi?id=34027

           Summary: Canvas globalCompositeOperation does not render
                    destination-in or destination-atop correctly
           Product: WebKit
           Version: 528+ (Nightly build)
          Platform: Macintosh Intel
               URL: https://developer.mozilla.org/samples/canvas-tutorial/
                    6_1_canvas_composite.html
        OS/Version: Mac OS X 10.6
            Status: UNCONFIRMED
          Severity: Major
          Priority: P2
         Component: Layout and Rendering
        AssignedTo: webkit-unassigned at lists.webkit.org
        ReportedBy: imgroxx at gmail.com


Created an attachment (id=47243)
 --> (https://bugs.webkit.org/attachment.cgi?id=47243)
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.

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