BackgroundPainter::paintFillLayers should check box-shadow when fin…

…ding an opaque layer https://bugs.webkit.org/show_bug.cgi?id=250882 rdar://problem/104722307 Reviewed by Antti Koivisto. This patch aligns WebKit with Gecko / Firefox and Blink / Chromium. Merge: https://chromium.googlesource.com/chromium/blink/+/a48f4540763c24adff42b9b77d719597f51482f6 BackgroundPainter::paintFillLayers has a fast path when a layer has an opaque background image. If a layer has an opaque background image, basically the layer's background layers will be hidden by the background image. So we can skip rendering the background layers. However, if box-shadow is also specified, the box-shadow will be rendered in a skipped background layer. This causes "box-shadow disappears". We cannot use the fast path if box-shadow is specified. * Source/WebCore/rendering/BackgroundPainter.cpp: (BackgroundPainter::paintFillLayers): * LayoutTests/fast/box-shadow/normal-box-shadow-with-background-image.html: Add Test Case * LayoutTests/fast/box-shadow/normal-box-shadow-with-background-image-expected-mismatch.html: Add Test Case Expectation Mismatch Canonical link: https://commits.webkit.org/275735@main
WebKit · Mar 6, 2024 · b6231f7 · b6231f7
1 parent c602819
commit b6231f7
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Showing 3 changed files with 35 additions and 2 deletions.
diff --git a/LayoutTests/fast/box-shadow/normal-box-shadow-with-background-image-expected-mismatch.html b/LayoutTests/fast/box-shadow/normal-box-shadow-with-background-image-expected-mismatch.html
@@ -0,0 +1,16 @@
+<!doctype html>
+<html>
+<head>
+<style>
+#theDiv {
+  height: 48px;
+  background-color: lightgrey;
+  width: 200px;
+  background-image: linear-gradient(red, lime), linear-gradient(blue, cyan);
+}
+</style>
+</head>
+<body>
+  <div id="theDiv"></div>
+</body>
+</html>
diff --git a/LayoutTests/fast/box-shadow/normal-box-shadow-with-background-image.html b/LayoutTests/fast/box-shadow/normal-box-shadow-with-background-image.html
@@ -0,0 +1,17 @@
+<!doctype html>
+<html>
+<head>
+<style>
+#theDiv {
+  height: 48px;
+  background-color: lightgrey;
+  box-shadow: black 0px 2px 4px;
+  width: 200px;
+  background-image: linear-gradient(red, green), linear-gradient(blue, cyan);
+}
+</style>
+</head>
+<body>
+  <div id="theDiv"></div>
+</body>
+</html>
diff --git a/Source/WebCore/rendering/BackgroundPainter.cpp b/Source/WebCore/rendering/BackgroundPainter.cpp
@@ -4,7 +4,7 @@
  *           (C) 2005 Allan Sandfeld Jensen (kde@carewolf.com)
  *           (C) 2005, 2006 Samuel Weinig (sam.weinig@gmail.com)
  * Copyright (C) 2005-2022 Apple Inc. All rights reserved.
- * Copyright (C) 2010 Google Inc. All rights reserved.
+ * Copyright (C) 2010-2013 Google Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
@@ -131,7 +131,7 @@ void BackgroundPainter::paintFillLayers(const Color& color, const FillLayer& fil
         // and pass it down.
 
         // The clipOccludesNextLayers condition must be evaluated first to avoid short-circuiting.
-        if (layer->clipOccludesNextLayers(layer == &fillLayer) && layer->hasOpaqueImage(m_renderer) && layer->image()->canRender(&m_renderer, m_renderer.style().effectiveZoom()) && layer->hasRepeatXY() && layer->blendMode() == BlendMode::Normal)
+        if (layer->clipOccludesNextLayers(layer == &fillLayer) && layer->hasOpaqueImage(m_renderer) && layer->image()->canRender(&m_renderer, m_renderer.style().effectiveZoom()) && layer->hasRepeatXY() && layer->blendMode() == BlendMode::Normal && !boxShadowShouldBeAppliedToBackground(m_renderer, rect.location(), bleedAvoidance, { }))
             break;
     }