| Summary: | fast/canvas/canvas-composite.html fails with bad antialiasing on source-out | ||||||||
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| Product: | WebKit | Reporter: | Adam Klein <adamk> | ||||||
| Component: | DOM | Assignee: | Nobody <webkit-unassigned> | ||||||
| Status: | RESOLVED DUPLICATE | ||||||||
| Severity: | Normal | CC: | benwells, jamesr, jchaffraix, mdelaney7, oliver, senorblanco, simon.fraser | ||||||
| Priority: | P2 | ||||||||
| Version: | 528+ (Nightly build) | ||||||||
| Hardware: | Unspecified | ||||||||
| OS: | Unspecified | ||||||||
| Attachments: |
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Created attachment 94860 [details]
image from CoreGraphics
here's a better example from coregraphics that doesn't have the same antialiasing issues as skia does.
I think the basic issue here is that the clipOut is antialiased, so the pixels on the edge have partial alpha, so they get partially filled in by the globalCompositeOperation, and then get partially cleared by the clear call. |
Created attachment 94856 [details] Bad source-out image Example result image attached. Notice the artifact of an outline on the top left of source-out.