| Summary: | ShouldPaintUsingCompositeCopy feature is not stable with respect to layouts, resizes or similar | ||||||
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| Product: | WebKit | Reporter: | Kimmo Kinnunen <kkinnunen> | ||||
| Component: | Compositing | Assignee: | Nobody <webkit-unassigned> | ||||
| Status: | NEW --- | ||||||
| Severity: | Normal | CC: | simon.fraser, webkit-bug-importer | ||||
| Priority: | P2 | Keywords: | InRadar | ||||
| Version: | WebKit Local Build | ||||||
| Hardware: | Unspecified | ||||||
| OS: | Unspecified | ||||||
| Bug Depends on: | 258964 | ||||||
| Bug Blocks: | |||||||
| Attachments: |
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Created attachment 466970 [details]
proposal for LayoutTests/compositing/canvas/
resize/print this and add debug print to inspect whether the canvas is painted with Copy or SourceOver
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Somehow on resizing and bringing up the print dialog, possibly just doing layout, the m_subpixelOffsetFromRenderer gets a small value such as ~0.18. This causes the optimization to be lost, because contentsBox "moves" away from the origo, even though in practice it does not. auto contents = contentsBox(); if (contents.location() != LayoutPoint(0, 0)) return false; E.g. repro case like: load page canvas gets the optimization resize canvas does not get the optimization reload canvas gets the optimization