computeDirtyRect 1760 Source/core/html/canvas/CanvasRenderingContext2D.cpp bool CanvasRenderingContext2D::computeDirtyRect(const FloatRect& localRect, FloatRect* dirtyRect) computeDirtyRect 1768 Source/core/html/canvas/CanvasRenderingContext2D.cpp bool CanvasRenderingContext2D::computeDirtyRect(const FloatRect& localRect, const FloatRect& transformedClipBounds, FloatRect* dirtyRect)