Modified: branches/chromium/1229/Source/WebCore/platform/graphics/chromium/cc/CCLayerTreeHostCommon.cpp (125578 => 125579)
--- branches/chromium/1229/Source/WebCore/platform/graphics/chromium/cc/CCLayerTreeHostCommon.cpp 2012-08-14 17:36:45 UTC (rev 125578)
+++ branches/chromium/1229/Source/WebCore/platform/graphics/chromium/cc/CCLayerTreeHostCommon.cpp 2012-08-14 17:46:23 UTC (rev 125579)
@@ -546,10 +546,10 @@
// The drawTransform that gets computed below is effectively the layer's drawTransform, unless
// the layer itself creates a renderSurface. In that case, the renderSurface re-parents the transforms.
WebTransformationMatrix drawTransform = combinedTransform;
+ // M[draw] = M[parent] * LT * Tr[anchor2center] * Tr[center2origin]
+ drawTransform.translate(-layer->bounds().width() / 2.0, -layer->bounds().height() / 2.0);
if (!layer->contentBounds().isEmpty() && !layer->bounds().isEmpty()) {
- // M[draw] = M[parent] * LT * Tr[anchor2center] * Tr[center2anchor]
- drawTransform.translate(-layer->bounds().width() / 2.0, -layer->bounds().height() / 2.0);
- // M[draw] = M[parent] * LT * Tr[anchor2origin] * S[content2layer]
+ // M[draw] = M[parent] * LT * Tr[anchor2origin] * S[layer2content]
drawTransform.scaleNonUniform(layer->bounds().width() / static_cast<double>(layer->contentBounds().width()),
layer->bounds().height() / static_cast<double>(layer->contentBounds().height()));
}
Modified: branches/chromium/1229/Source/WebKit/chromium/tests/CCLayerTreeHostCommonTest.cpp (125578 => 125579)
--- branches/chromium/1229/Source/WebKit/chromium/tests/CCLayerTreeHostCommonTest.cpp 2012-08-14 17:36:45 UTC (rev 125578)
+++ branches/chromium/1229/Source/WebKit/chromium/tests/CCLayerTreeHostCommonTest.cpp 2012-08-14 17:46:23 UTC (rev 125579)
@@ -948,6 +948,36 @@
EXPECT_TRANSFORMATION_MATRIX_EQ(expectedGrandChildScreenSpaceTransform, grandChild->screenSpaceTransform());
}
+TEST(CCLayerTreeHostCommonTest, verifyTransformsForDegenerateIntermediateLayer)
+{
+ // A layer that is empty in one axis, but not the other, was accidentally skipping a necessary translation.
+ // Without that translation, the coordinate space of the layer's drawTransform is incorrect.
+ //
+ // Normally this isn't a problem, because the layer wouldn't be drawn anyway, but if that layer becomes a renderSurface, then
+ // its drawTransform is implicitly inherited by the rest of the subtree, which then is positioned incorrectly as a result.
+
+ RefPtr<LayerChromium> root = LayerChromium::create();
+ RefPtr<LayerChromium> child = LayerChromium::create();
+ RefPtr<LayerChromiumWithForcedDrawsContent> grandChild = adoptRef(new LayerChromiumWithForcedDrawsContent());
+
+ // The child height is zero, but has non-zero width that should be accounted for while computing drawTransforms.
+ const WebTransformationMatrix identityMatrix;
+ setLayerPropertiesForTesting(root.get(), identityMatrix, identityMatrix, FloatPoint::zero(), FloatPoint::zero(), IntSize(100, 100), false);
+ setLayerPropertiesForTesting(child.get(), identityMatrix, identityMatrix, FloatPoint::zero(), FloatPoint::zero(), IntSize(10, 0), false);
+ setLayerPropertiesForTesting(grandChild.get(), identityMatrix, identityMatrix, FloatPoint::zero(), FloatPoint::zero(), IntSize(10, 10), false);
+
+ root->addChild(child);
+ child->addChild(grandChild);
+ child->setForceRenderSurface(true);
+
+ executeCalculateDrawTransformsAndVisibility(root.get());
+
+ ASSERT_TRUE(child->renderSurface());
+ EXPECT_TRANSFORMATION_MATRIX_EQ(identityMatrix, child->renderSurface()->drawTransform()); // This is the real test, the rest are sanity checks.
+ EXPECT_TRANSFORMATION_MATRIX_EQ(identityMatrix, child->drawTransform());
+ EXPECT_TRANSFORMATION_MATRIX_EQ(identityMatrix, grandChild->drawTransform());
+}
+
TEST(CCLayerTreeHostCommonTest, verifyRenderSurfaceListForRenderSurfaceWithClippedLayer)
{
RefPtr<LayerChromium> parent = LayerChromium::create();
