cc: Handle transform between transform tree target and render target
A fixed-position layer's transform tree parent may be an ancestor of
the layer's render target's transform tree node, since layers on the
path from the fixed-position layer to its containing layer may own
render surfaces. This means that the target space transform that the
fixed position layer gets from its transform tree parent is with
respect to a different render target. This CL makes draw transform
computation account for that difference.
BUG=386810
Review URL: https://codereview.chromium.org/1027873002
Cr-Commit-Position: refs/heads/master@{#321694}
diff --git a/cc/trees/layer_tree_host_common_unittest.cc b/cc/trees/layer_tree_host_common_unittest.cc
index e3a48bfed..d18c1c8 100644
--- a/cc/trees/layer_tree_host_common_unittest.cc
+++ b/cc/trees/layer_tree_host_common_unittest.cc
@@ -7646,6 +7646,55 @@
EXPECT_TRUE(render_surface_layer_list.at(2)->render_surface());
}
+TEST_F(LayerTreeHostCommonTest, FixedPositionWithInterveningRenderSurface) {
+ // Ensures that when we have a render surface between a fixed position layer
+ // and its container, we compute the fixed position layer's draw transform
+ // with respect to that intervening render surface, not with respect to its
+ // container's render target.
+ //
+ // + root
+ // + render_surface
+ // + fixed
+ //
+ scoped_refptr<Layer> root = Layer::Create();
+ scoped_refptr<LayerWithForcedDrawsContent> render_surface =
+ make_scoped_refptr(new LayerWithForcedDrawsContent());
+ scoped_refptr<LayerWithForcedDrawsContent> fixed =
+ make_scoped_refptr(new LayerWithForcedDrawsContent());
+
+ root->AddChild(render_surface);
+ render_surface->AddChild(fixed);
+
+ root->SetIsContainerForFixedPositionLayers(true);
+ render_surface->SetForceRenderSurface(true);
+
+ LayerPositionConstraint constraint;
+ constraint.set_is_fixed_position(true);
+ fixed->SetPositionConstraint(constraint);
+
+ SetLayerPropertiesForTesting(root.get(), gfx::Transform(), gfx::Point3F(),
+ gfx::PointF(), gfx::Size(50, 50), true, false);
+ SetLayerPropertiesForTesting(render_surface.get(), gfx::Transform(),
+ gfx::Point3F(), gfx::PointF(7.f, 9.f),
+ gfx::Size(50, 50), true, false);
+ SetLayerPropertiesForTesting(fixed.get(), gfx::Transform(), gfx::Point3F(),
+ gfx::PointF(10.f, 15.f), gfx::Size(50, 50), true,
+ false);
+
+ scoped_ptr<FakeLayerTreeHost> host(CreateFakeLayerTreeHost());
+ host->SetRootLayer(root);
+
+ ExecuteCalculateDrawProperties(root.get());
+
+ gfx::Transform expected_draw_transform;
+ expected_draw_transform.Translate(10.f, 15.f);
+ EXPECT_EQ(expected_draw_transform, fixed->draw_transform());
+
+ gfx::Transform expected_screen_space_transform;
+ expected_screen_space_transform.Translate(17.f, 24.f);
+ EXPECT_EQ(expected_screen_space_transform, fixed->screen_space_transform());
+}
+
TEST_F(LayerTreeHostCommonTest, ScrollCompensationWithRounding) {
// This test verifies that a scrolling layer that gets snapped to
// integer coordinates doesn't move a fixed position child.
