Bug 265365

Summary: [CoordinatedGraphics] Canvas 2D rendering context causes unnecessary tile invalidations
Product: WebKit Reporter: Jani Hautakangas <jani>
Component: CanvasAssignee: Nobody <webkit-unassigned>
Status: RESOLVED FIXED    
Severity: Normal CC: dino, webkit-bug-importer
Priority: P2 Keywords: InRadar
Version: WebKit Nightly Build   
Hardware: Unspecified   
OS: Unspecified   

Description Jani Hautakangas 2023-11-27 01:37:55 PST 
CanvasRenderingContext2DBase tracks one dirty rect and does union of all incoming dirty rects within repaint cycle.
In coordinated graphics, canvas is tiled and this unification of rects causes unnecessary invalidation of tiles which
are not dirty. For example in case where canvas spans over multiple tiles and only small areas at top-left and
bottom-right corners of canvas are changed. This scenario causes whole canvas and all tiles to be marked dirty because
of unification of dirty areas although only top-left and bottom-right tiles are actually dirty.
Comment 1 Jani Hautakangas 2023-11-27 01:44:40 PST 
In coordinated graphics tiles do dirty rect unification internally
Comment 2 Jani Hautakangas 2023-11-27 01:50:17 PST 
Pull request: https://github.com/WebKit/WebKit/pull/20917
Comment 3 EWS 2023-11-27 07:02:03 PST 
Committed 271139@main (b2410e35eca0): <https://commits.webkit.org/271139@main>

Reviewed commits have been landed. Closing PR #20917 and removing active labels.
Comment 4 Radar WebKit Bug Importer 2023-11-27 07:03:14 PST 
<rdar://problem/118832308>