[cairo] BackingStore::incorporateUpdate should use CompositeCopy to support drawsBack...
authorcommit-queue@webkit.org <commit-queue@webkit.org@268f45cc-cd09-0410-ab3c-d52691b4dbfc>
Mon, 19 Nov 2018 21:22:51 +0000 (21:22 +0000)
committercommit-queue@webkit.org <commit-queue@webkit.org@268f45cc-cd09-0410-ab3c-d52691b4dbfc>
Mon, 19 Nov 2018 21:22:51 +0000 (21:22 +0000)
commit1bc7d747eee931c8830c66d7b4a5aa20bae36271
tree2d731fa970916c154111dfac0204578dc7e8473e
parentad6f370b75d3b2c0b75764151f9776ce28e40398
[cairo] BackingStore::incorporateUpdate should use CompositeCopy to support drawsBackground=false in general Cairo ports
https://bugs.webkit.org/show_bug.cgi?id=191577

Patch by Tomoki Imai <Tomoki.Imai@sony.com> on 2018-11-19
Reviewed by Carlos Garcia Campos.

We should use CompositeCopy operator to update bitmap to overwrite existing bitmap even if source contains
transparent parts. It enables ports which uses Cairo to set drawsBackground to false.
GTK ports has custom background extension, and in such case, we need to use CompositeSourceOver to retain
custom background.

* UIProcess/cairo/BackingStoreCairo.cpp:
(WebKit::BackingStore::incorporateUpdate): Use CompositeCopy operator to update bitmap.

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@238379 268f45cc-cd09-0410-ab3c-d52691b4dbfc
Source/WebKit/ChangeLog
Source/WebKit/UIProcess/cairo/BackingStoreCairo.cpp