Bug 34027

Summary:

Canvas globalCompositeOperation does not render destination-in or destination-atop correctly

Product:

WebKit

Reporter:

Steven Littiebrant <imgroxx>

Component:

Layout and Rendering

Assignee:

Nobody <webkit-unassigned>

Status:

RESOLVED DUPLICATE

Severity:

Major

CC:

hamaji, mdelaney7

Priority:

Keywords:

HasReduction

Version:

528+ (Nightly build)

Hardware:

Mac (Intel)

OS:

OS X 10.6

URL:

https://developer.mozilla.org/samples/canvas-tutorial/6_1_canvas_composite.html

Attachments:

Description	Flags
my render results - note destination-in and destination-atop	none
Reduction	none
Correct render results	none

Steven Littiebrant

Reported 2010-01-22 16:30:00 PST

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.

Attachments
my render results - note destination-in and destination-atop (12.60 KB, image/png) 2010-01-22 16:30 PST, Steven Littiebrant	no flags	Details
Reduction (1.17 KB, text/html) 2010-01-22 16:45 PST, Steven Littiebrant	no flags	Details
Correct render results (5.96 KB, image/png) 2010-01-22 16:52 PST, Steven Littiebrant	no flags	Details
View All Add attachment proposed patch, testcase, etc.

Steven Littiebrant

Comment 1 2010-01-22 16:45:24 PST

Created attachment 47245 [details] Reduction Code is modified from the Mozilla website linked originally.

Steven Littiebrant

Comment 2 2010-01-22 16:52:52 PST

Created attachment 47246 [details] Correct render results Also from the Mozilla site, these are what should have rendered.

Steven Littiebrant

Comment 3 2010-02-01 13:43:16 PST

Noted that it has a reduction.

Shinichiro Hamaji

Comment 4 2010-08-16 03:25:16 PDT

Merging this bug as Bug 39177 seems to be more generic. *** This bug has been marked as a duplicate of bug 39177 ***

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