Overlap map for compositing should ignore empty layers

https://bugs.webkit.org/show_bug.cgi?id=63499 Reviewed by Simon Fraser. Source/WebCore: Test: compositing/layer-creation/overlap-empty-layer.html * rendering/RenderLayerCompositor.cpp: (WebCore::RenderLayerCompositor::addToOverlapMap): (WebCore::RenderLayerCompositor::computeCompositingRequirements): LayoutTests: * compositing/layer-creation/overlap-empty-layer-expected.txt: Added. * compositing/layer-creation/overlap-empty-layer.html: Added. Canonical link: https://commits.webkit.org/97606@main git-svn-id: https://svn.webkit.org/repository/webkit/trunk@109981 268f45cc-cd09-0410-ab3c-d52691b4dbfc
WebKit · Mar 7, 2012 · 1365e58 · 1365e58
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diff --git a/LayoutTests/ChangeLog b/LayoutTests/ChangeLog
@@ -1,3 +1,13 @@
+2012-03-06  Adrienne Walker  <enne@google.com>
+
+        Overlap map for compositing should ignore empty layers
+        https://bugs.webkit.org/show_bug.cgi?id=63499
+
+        Reviewed by Simon Fraser.
+
+        * compositing/layer-creation/overlap-empty-layer-expected.txt: Added.
+        * compositing/layer-creation/overlap-empty-layer.html: Added.
+
 2012-03-06  Kent Tamura  <tkent@chromium.org>
 
         [Chromium] Rebaseline of input-appearance-numberandspeech.html for r109876.

diff --git a/LayoutTests/compositing/layer-creation/overlap-empty-layer-expected.txt b/LayoutTests/compositing/layer-creation/overlap-empty-layer-expected.txt
@@ -0,0 +1,23 @@
+(GraphicsLayer
+  (bounds 842.00 600.00)
+  (children 1
+    (GraphicsLayer
+      (bounds 842.00 600.00)
+      (children 1
+        (GraphicsLayer
+          (position 8.00 8.00)
+          (bounds 784.00 0.00)
+          (transform [1.00 0.00 0.00 0.00] [0.00 1.00 0.00 0.00] [0.00 0.00 1.00 0.00] [50.00 50.00 0.00 1.00])
+          (children 1
+            (GraphicsLayer
+              (position 200.00 200.00)
+              (bounds 80.00 80.00)
+              (drawsContent 1)
+            )
+          )
+        )
+      )
+    )
+  )
+)
+
diff --git a/LayoutTests/compositing/layer-creation/overlap-empty-layer.html b/LayoutTests/compositing/layer-creation/overlap-empty-layer.html
@@ -0,0 +1,51 @@
+<html>
+<head>
+<style>
+    body {
+        overflow: hidden;
+    }
+
+    #container {
+        -webkit-transform: translate(50px, 50px);
+    }
+
+    #composited {
+        -webkit-transform:translateZ(0);
+        position:absolute;
+        top: 200px;
+        left: 200px;
+        width: 80px;
+        height: 80px;
+        background-color: blue;
+    }
+
+    #overlap {
+        position: absolute;
+        top: 0px;
+        left: 0px;
+        width: 100px;
+        height: 100px;
+        background-color: blue;
+    }
+</style>
+<script>
+    if (window.layoutTestController) {
+        layoutTestController.dumpAsText(false);
+        window.addEventListener('load', function() {
+            document.getElementById("layertree").innerText = layoutTestController.layerTreeAsText();
+        }, false);
+    }
+</script>
+</head>
+<body>
+    <div id="container">
+        <div id="composited"></div>
+    </div>
+
+    <!-- This overlaps all of container, but not the composited child. -->
+    <!-- It should not get its own composited layer. -->
+    <div id="overlap"></div>
+
+    <pre id="layertree"></pre>
+</body>
+</html>
diff --git a/Source/WebCore/ChangeLog b/Source/WebCore/ChangeLog
@@ -1,3 +1,16 @@
+2012-03-06  Adrienne Walker  <enne@google.com>
+
+        Overlap map for compositing should ignore empty layers
+        https://bugs.webkit.org/show_bug.cgi?id=63499
+
+        Reviewed by Simon Fraser.
+
+        Test: compositing/layer-creation/overlap-empty-layer.html
+
+        * rendering/RenderLayerCompositor.cpp:
+        (WebCore::RenderLayerCompositor::addToOverlapMap):
+        (WebCore::RenderLayerCompositor::computeCompositingRequirements):
+
 2012-03-06  Vangelis Kokkevis  <vangelis@chromium.org>
 
         [chromium] Increase the accelerated canvas min size to 256 * 256

diff --git a/Source/WebCore/rendering/RenderLayerCompositor.cpp b/Source/WebCore/rendering/RenderLayerCompositor.cpp
@@ -638,12 +638,12 @@ void RenderLayerCompositor::addToOverlapMap(OverlapMap& overlapMap, RenderLayer*
 
     if (!boundsComputed) {
         layerBounds = layer->renderer()->localToAbsoluteQuad(FloatRect(layer->localBoundingBox())).enclosingBoundingBox();
-        // Empty rects never intersect, but we need them to for the purposes of overlap testing.
-        if (layerBounds.isEmpty())
-            layerBounds.setSize(IntSize(1, 1));
         boundsComputed = true;
     }
 
+    if (layerBounds.isEmpty())
+        return;
+
     IntRect clipRect = pixelSnappedIntRect(layer->backgroundClipRect(rootRenderLayer(), 0, true).rect()); // FIXME: Incorrect for CSS regions.
     clipRect.scale(pageScaleFactor());
     clipRect.intersect(layerBounds);
@@ -715,8 +715,6 @@ void RenderLayerCompositor::computeCompositingRequirements(RenderLayer* layer, O
         // If we're testing for overlap, we only need to composite if we overlap something that is already composited.
         absBounds = layer->renderer()->localToAbsoluteQuad(FloatRect(layer->localBoundingBox())).enclosingBoundingBox();
         // Empty rects never intersect, but we need them to for the purposes of overlap testing.
-        if (absBounds.isEmpty())
-            absBounds.setSize(IntSize(1, 1));
         haveComputedBounds = true;
         mustOverlapCompositedLayers = overlapMap->overlapsLayers(absBounds);
     }