Right now -webkit-background-composite only applies to images. This should also apply to background color fills.
Created attachment 9703 [details] Test Case This test case renders a red background. If the composite mode applies the rendering will be black (or transparent if you enable Safari transparent window mode.)
Created attachment 11545 [details] Proposed patch Makes -webkit-background-composite apply to background-color. Adds compositeOperation() function to GraphicsContext. Fixes functions in GraphicsContext that never drew when alpha() was 0, this optimization only works when the compositeOperation is SourceOver. * manual-tests/background-composite-color.html: Added. * platform/graphics/GraphicsContext.h: * platform/graphics/cg/GraphicsContextCG.cpp: (WebCore::GraphicsContext::drawRect): check the compositeOperation (WebCore::GraphicsContext::drawEllipse): ditto (WebCore::GraphicsContext::drawConvexPolygon): ditto (WebCore::GraphicsContext::fillRect): ditto * platform/mac/GraphicsContextMac.mm: (WebCore::GraphicsContext::compositeOperation): Added. * rendering/RenderBox.cpp: (WebCore::RenderBox::paintBackgroundExtended):
Comment on attachment 11545 [details] Proposed patch r=me!
Comment on attachment 11545 [details] Proposed patch Clearing bdakin's r+ since this patch has bit-rotten.
Created attachment 12134 [details] Updated patch to fix bit rottenness This patch applies cleanly now, but it causes an assertion failure while running layout tests on a locally-built debug build of WebKit r18491 with Safari 2.0.4 (419.3) on Mac OS X 10.4.8 (8N1037). The assertion failure occurs on editing/pasteboard/subframe-dragndrop-1.html (as well as when simply clicking on a link after Safari opened with the test results!): ASSERTION FAILED: !paintingDisabled() (/.../WebKit/WebCore/platform/graphics/cg/GraphicsContextCG.cpp:89 CGContext* WebCore::GraphicsContext::platformContext() const) Segmentation fault 0 com.apple.WebCore 0x013d169c WebCore::GraphicsContext::platformContext() const + 74 (GraphicsContextCG.cpp :89) 1 com.apple.WebCore 0x013d53b7 WebCore::GraphicsContext::compositeOperation() + 89 (GraphicsContextMac.mm:10 5) 2 com.apple.WebCore 0x0115cdba WebCore::RenderBox::paintBackgroundExtended(WebCore::GraphicsContext*, WebCor e::Color const&, WebCore::BackgroundLayer const*, int, int, int, int, int, int, int, int, int, int) + 1680 (RenderBox.cp p:514) 3 com.apple.WebCore 0x0115b933 WebCore::RenderBox::paintBackground(WebCore::GraphicsContext*, WebCore::Color const&, WebCore::BackgroundLayer const*, int, int, int, int, int, int) + 201 (RenderBox.cpp:392) 4 com.apple.WebCore 0x0115b9e8 WebCore::RenderBox::paintBackgrounds(WebCore::GraphicsContext*, WebCore::Colo r const&, WebCore::BackgroundLayer const*, int, int, int, int, int, int) + 174 (RenderBox.cpp:386) 5 com.apple.WebCore 0x0115bd82 WebCore::RenderBox::paintRootBoxDecorations(WebCore::RenderObject::PaintInfo& , int, int) + 920 (RenderBox.cpp:340) 6 com.apple.WebCore 0x0115be76 WebCore::RenderBox::paintBoxDecorations(WebCore::RenderObject::PaintInfo&, in t, int) + 86 (RenderBox.cpp:350) 7 com.apple.WebCore 0x011560ab WebCore::RenderBlock::paintObject(WebCore::RenderObject::PaintInfo&, int, int ) + 163 (RenderBlock.cpp:1355) 8 com.apple.WebCore 0x0114ed55 WebCore::RenderBlock::paint(WebCore::RenderObject::PaintInfo&, int, int) + 46 7 (RenderBlock.cpp:1286) 9 com.apple.WebCore 0x0117d8ce WebCore::RenderLayer::paintLayer(WebCore::RenderLayer*, WebCore::GraphicsCont ext*, WebCore::IntRect const&, bool, WebCore::PaintRestriction, WebCore::RenderObject*) + 864 (RenderLayer.cpp:1411) 10 com.apple.WebCore 0x0117dccc WebCore::RenderLayer::paintLayer(WebCore::RenderLayer*, WebCore::GraphicsCont ext*, WebCore::IntRect const&, bool, WebCore::PaintRestriction, WebCore::RenderObject*) + 1886 (RenderLayer.cpp:1462) 11 com.apple.WebCore 0x0117dd94 WebCore::RenderLayer::paint(WebCore::GraphicsContext*, WebCore::IntRect const &, WebCore::PaintRestriction, WebCore::RenderObject*) + 60 (RenderLayer.cpp:1331) 12 com.apple.WebCore 0x010dcb63 WebCore::Frame::paint(WebCore::GraphicsContext*, WebCore::IntRect const&) + 5 39 (Frame.cpp:1045) 13 com.apple.WebCore 0x010dd58d WebCore::Frame::setIsActive(bool) + 795 (Frame.cpp:1254) 14 com.apple.WebKit 0x0033eabb -[WebHTMLView(WebPrivate) _updateActiveState] + 311 (WebHTMLView.m:1805) 15 com.apple.WebKit 0x00342b9b -[WebHTMLView windowDidBecomeKey:] + 213 (WebHTMLView.m:2777) 16 com.apple.Foundation 0x925f0207 _nsnote_callback + 230 17 com.apple.CoreFoundation 0x908543f6 __CFXNotificationPost + 345 18 com.apple.CoreFoundation 0x9084bc11 _CFXNotificationPostNotification + 600 19 com.apple.Foundation 0x925e8860 -[NSNotificationCenter postNotificationName:object:userInfo:] + 121 20 com.apple.Foundation 0x925ef755 -[NSNotificationCenter postNotificationName:object:] + 55 21 com.apple.AppKit 0x9334ff09 -[NSWindow becomeKeyWindow] + 746 22 com.apple.Safari 0x000259e4 0x1000 + 149988 23 com.apple.AppKit 0x9334efa0 _NXShowKeyAndMain + 365 24 com.apple.AppKit 0x9335bdf1 -[NSWindow sendEvent:] + 3809 25 com.apple.Safari 0x000230c6 0x1000 + 139462 26 com.apple.AppKit 0x9334e350 -[NSApplication sendEvent:] + 5023 27 com.apple.Safari 0x00022c56 0x1000 + 138326 28 com.apple.AppKit 0x93278dfe -[NSApplication run] + 547 29 com.apple.AppKit 0x9326cd2f NSApplicationMain + 573 30 com.apple.Safari 0x0005f54a 0x1000 + 386378 31 com.apple.Safari 0x0005f471 0x1000 + 386161
The patch did not apply cleanly to feature-branch, however I imagine this bug would be pretty easy to finish once feature-branch/trunk calm down. (Assuming it's still desired. -webkit-background-composite seems like a rather odd feature).
Bug 234661 is removing -webkit-background-composite.