Compute accurate screen space bounds for animated layers.

This walks up the layer tree transforming a layer's bounds as a box
through the different layer transforms and uses the
LayerAnimationController::AnimationBoundsForBox to transform the box at
layers which are animated.

Expansion of the box is included for filters which change the bounds,
however, the LayerAnimationController implementation is currently stubbed.

+ Added computation of animation bounds of layers in the screen space.
- Removed invalid assertion in LayerAnimationControllerTest.AnimatedBounds.
~ Renamed methods to use the uniform naming AnimationBounds.
~ Extracted LTHC::ApplySublayerTransformAboutAnchor from
  LTHC::CalculateDrawPropertiesInternal.
~ Fixed LayerImpl::AsValueInto to correctly calculate bounds.
! Did not substitute implementation of ApplySublayerTransformAboutAnchor
  inside CalculateDrawPropertiesInternal due to performance regression.


BUG=280375

Review URL: https://codereview.chromium.org/109193002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@246767 0039d316-1c4b-4281-b951-d872f2087c98

6 files changed, 460 insertions, 17 deletions

diff --git a/cc/layers/layer.h b/cc/layers/layer.h
index 5f9caf6..df358f2 100644
--- a/cc/layers/layer.h
+++ b/cc/layers/layer.h
@@ -397,10 +397,6 @@ class CC_EXPORT Layer : public base::RefCounted<Layer>,
   void PauseAnimation(int animation_id, double time_offset);
   void RemoveAnimation(int animation_id);
 
-  bool AnimatedBoundsForBox(const gfx::BoxF& box, gfx::BoxF* bounds) {
-    return layer_animation_controller_->AnimatedBoundsForBox(box, bounds);
-  }
-
   LayerAnimationController* layer_animation_controller() {
     return layer_animation_controller_.get();
   }
diff --git a/cc/layers/layer_impl.cc b/cc/layers/layer_impl.cc
index 7444b77..beb282d 100644
--- a/cc/layers/layer_impl.cc
+++ b/cc/layers/layer_impl.cc
@@ -17,10 +17,12 @@
 #include "cc/debug/micro_benchmark_impl.h"
 #include "cc/debug/traced_value.h"
 #include "cc/input/layer_scroll_offset_delegate.h"
+#include "cc/layers/layer_utils.h"
 #include "cc/layers/painted_scrollbar_layer_impl.h"
 #include "cc/layers/quad_sink.h"
 #include "cc/output/copy_output_request.h"
 #include "cc/quads/debug_border_draw_quad.h"
+#include "cc/trees/layer_tree_host_common.h"
 #include "cc/trees/layer_tree_impl.h"
 #include "cc/trees/layer_tree_settings.h"
 #include "cc/trees/proxy.h"
@@ -1305,13 +1307,13 @@ void LayerImpl::AsValueInto(base::DictionaryValue* state) const {
   state->SetBoolean("can_use_lcd_text", can_use_lcd_text());
   state->SetBoolean("contents_opaque", contents_opaque());
 
-  if (layer_animation_controller_->IsAnimatingProperty(Animation::Transform) ||
-      layer_animation_controller_->IsAnimatingProperty(Animation::Filter)) {
-    gfx::BoxF box(bounds().width(), bounds().height(), 0.f);
-    gfx::BoxF inflated;
-    if (layer_animation_controller_->AnimatedBoundsForBox(box, &inflated))
-      state->Set("animated_bounds", MathUtil::AsValue(inflated).release());
-  }
+  state->SetBoolean(
+      "has_animation_bounds",
+      layer_animation_controller()->HasAnimationThatInflatesBounds());
+
+  gfx::BoxF box;
+  if (LayerUtils::GetAnimationBounds(*this, &box))
+    state->Set("animation_bounds", MathUtil::AsValue(box).release());
 
   if (debug_info_.get()) {
     std::string str;
diff --git a/cc/layers/layer_impl.h b/cc/layers/layer_impl.h
index 75f02ec..66fa84b 100644
--- a/cc/layers/layer_impl.h
+++ b/cc/layers/layer_impl.h
@@ -350,12 +350,6 @@ class CC_EXPORT LayerImpl : public LayerAnimationValueObserver,
   float contents_scale_y() const { return draw_properties_.contents_scale_y; }
   void SetContentsScale(float contents_scale_x, float contents_scale_y);
 
-  // Computes a box in screen space that should entirely contain the layer's
-  // bounds through the entirety of the layer's current animation. Returns true
-  // and sets |out| to the inflation if there are animations that can inflate
-  // bounds in the path to the root layer. Returns false otherwise.
-  bool GetAnimationBounds(gfx::BoxF* out) const { return false; }
-
   virtual void CalculateContentsScale(float ideal_contents_scale,
                                       float device_scale_factor,
                                       float page_scale_factor,
@@ -465,6 +459,10 @@ class CC_EXPORT LayerImpl : public LayerAnimationValueObserver,
     return layer_animation_controller_.get();
   }
 
+  const LayerAnimationController* layer_animation_controller() const {
+    return layer_animation_controller_.get();
+  }
+
   virtual Region VisibleContentOpaqueRegion() const;
 
   virtual void DidBecomeActive();
diff --git a/cc/layers/layer_utils.cc b/cc/layers/layer_utils.cc
new file mode 100644
index 0000000..7da41a3
--- /dev/null
+++ b/cc/layers/layer_utils.cc
@@ -0,0 +1,160 @@
+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "cc/layers/layer_utils.h"
+
+#include "cc/layers/layer_impl.h"
+#include "cc/trees/layer_tree_host_common.h"
+#include "ui/gfx/box_f.h"
+
+namespace cc {
+
+namespace {
+
+bool HasAnimationThatInflatesBounds(const LayerImpl& layer) {
+  return layer.layer_animation_controller()->HasAnimationThatInflatesBounds();
+}
+
+bool HasFilterAnimationThatInflatesBounds(const LayerImpl& layer) {
+  return layer.layer_animation_controller()
+      ->HasFilterAnimationThatInflatesBounds();
+}
+
+bool HasTransformAnimationThatInflatesBounds(const LayerImpl& layer) {
+  return layer.layer_animation_controller()
+      ->HasTransformAnimationThatInflatesBounds();
+}
+
+inline bool HasAncestorTransformAnimation(const LayerImpl& layer) {
+  return layer.screen_space_transform_is_animating();
+}
+
+inline bool HasAncestorFilterAnimation(const LayerImpl& layer) {
+  for (const LayerImpl* current = &layer; current;
+       current = current->parent()) {
+    if (HasFilterAnimationThatInflatesBounds(*current))
+        return true;
+  }
+
+  return false;
+}
+
+}  // namespace
+
+bool LayerUtils::GetAnimationBounds(const LayerImpl& layer_in, gfx::BoxF* out) {
+  // We don't care about animated bounds for invisible layers.
+  if (!layer_in.DrawsContent())
+    return false;
+
+  // We also don't care for layers that are not animated or a child of an
+  // animated layer.
+  if (!HasAncestorTransformAnimation(layer_in) &&
+      !HasAncestorFilterAnimation(layer_in))
+    return false;
+
+  // To compute the inflated bounds for a layer, we start by taking its bounds
+  // and converting it to a 3d box, and then we transform or inflate it
+  // repeatedly as we walk up the layer tree to the root.
+  //
+  // At each layer we apply the following transformations to the box:
+  //   1) We translate so that the anchor point is the origin.
+  //   2) We either apply the layer's transform or inflate if the layer's
+  //      transform is animated.
+  //   3) We undo the translation from step 1 and apply a second translation
+  //      to account for the layer's position.
+  //   4) We apply the sublayer transform from our parent (about the parent's
+  //      anchor point).
+  //
+  gfx::BoxF box(layer_in.bounds().width(), layer_in.bounds().height(), 0.f);
+
+  // We want to inflate/transform the box as few times as possible. Each time
+  // we do this, we have to make the box axis aligned again, so if we make many
+  // small adjustments to the box by transforming it repeatedly rather than
+  // once by the product of all these matrices, we will accumulate a bunch of
+  // unnecessary inflation because of the the many axis-alignment fixes. This
+  // matrix stores said product.
+  gfx::Transform coalesced_transform;
+
+  for (const LayerImpl* layer = &layer_in; layer; layer = layer->parent()) {
+    int anchor_x = layer->anchor_point().x() * layer->bounds().width();
+    int anchor_y = layer->anchor_point().y() * layer->bounds().height();
+    gfx::PointF position = layer->position();
+    if (layer->parent() && !HasAnimationThatInflatesBounds(*layer)) {
+      // |composite_layer_transform| contains 1 - 4 mentioned above. We compute
+      // it separately and apply afterwards because it's a bit more efficient
+      // because post-multiplication appears a bit more expensive, so we want
+      // to do it only once.
+      gfx::Transform composite_layer_transform;
+
+      if (!layer->parent()->sublayer_transform().IsIdentity()) {
+        LayerTreeHostCommon::ApplySublayerTransformAboutAnchor(
+            *layer->parent(),
+            layer->parent()->bounds(),
+            &composite_layer_transform);
+      }
+
+      composite_layer_transform.Translate3d(anchor_x + position.x(),
+                                            anchor_y + position.y(),
+                                            layer->anchor_point_z());
+      composite_layer_transform.PreconcatTransform(layer->transform());
+      composite_layer_transform.Translate3d(
+          -anchor_x, -anchor_y, -layer->anchor_point_z());
+
+      // Add this layer's contributions to the |coalesced_transform|.
+      coalesced_transform.ConcatTransform(composite_layer_transform);
+      continue;
+    }
+
+    // First, apply coalesced transform we've been building and reset it.
+    coalesced_transform.TransformBox(&box);
+    coalesced_transform.MakeIdentity();
+
+    // We need to apply the inflation about the layer's anchor point. Rather
+    // than doing this via transforms, we'll just shift the box directly.
+    box.set_origin(box.origin() + gfx::Vector3dF(-anchor_x,
+                                                 -anchor_y,
+                                                 -layer->anchor_point_z()));
+
+    // Perform the inflation
+    if (HasFilterAnimationThatInflatesBounds(*layer)) {
+      gfx::BoxF inflated;
+      if (!layer->layer_animation_controller()->FilterAnimationBoundsForBox(
+              box, &inflated))
+        return false;
+      box = inflated;
+    }
+
+    if (HasTransformAnimationThatInflatesBounds(*layer)) {
+      gfx::BoxF inflated;
+      if (!layer->layer_animation_controller()->TransformAnimationBoundsForBox(
+              box, &inflated))
+        return false;
+      box = inflated;
+    }
+
+    // Apply step 3) mentioned above.
+    box.set_origin(box.origin() + gfx::Vector3dF(anchor_x + position.x(),
+                                                 anchor_y + position.y(),
+                                                 layer->anchor_point_z()));
+
+    // Even for layers with animations, we have to tack in the sublayer
+    // transform of our parent. *Every* layer is repsonsible for including the
+    // sublayer transform of its parent (see step 4 above).
+    if (layer->parent()) {
+      LayerTreeHostCommon::ApplySublayerTransformAboutAnchor(
+          *layer->parent(), layer->parent()->bounds(), &coalesced_transform);
+    }
+  }
+
+  // If we've got an unapplied coalesced transform at this point, it must still
+  // be applied.
+  if (!coalesced_transform.IsIdentity())
+    coalesced_transform.TransformBox(&box);
+
+  *out = box;
+
+  return true;
+}
+
+}  // namespace cc
diff --git a/cc/layers/layer_utils.h b/cc/layers/layer_utils.h
new file mode 100644
index 0000000..396f070
--- /dev/null
+++ b/cc/layers/layer_utils.h
@@ -0,0 +1,29 @@
+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CC_LAYERS_LAYER_UTILS_H_
+#define CC_LAYERS_LAYER_UTILS_H_
+
+#include "cc/base/cc_export.h"
+
+namespace gfx {
+  class BoxF;
+}  // namespace gfx
+
+namespace cc {
+  class LayerImpl;
+
+  class CC_EXPORT LayerUtils {
+   public:
+    // Computes a box in screen space that should entirely contain the layer's
+    // bounds through the entirety of the layer's current animation. Returns
+    // true and sets |out| to the inflation if there are animations that can
+    // inflate bounds in the path to the root layer and that it was able to
+    // inflate correctly. Returns false otherwise.
+    static bool GetAnimationBounds(const LayerImpl& layer, gfx::BoxF* out);
+  };
+
+}  // namespace cc
+
+#endif  // CC_LAYERS_LAYER_UTILS_H_
diff --git a/cc/layers/layer_utils_unittest.cc b/cc/layers/layer_utils_unittest.cc
new file mode 100644
index 0000000..9738f60
--- /dev/null
+++ b/cc/layers/layer_utils_unittest.cc
@@ -0,0 +1,258 @@
+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "cc/layers/layer_utils.h"
+
+#include "cc/animation/transform_operations.h"
+#include "cc/layers/layer_impl.h"
+#include "cc/test/animation_test_common.h"
+#include "cc/test/fake_impl_proxy.h"
+#include "cc/test/fake_layer_tree_host_impl.h"
+#include "testing/gtest/include/gtest/gtest.h"
+#include "ui/gfx/box_f.h"
+#include "ui/gfx/test/gfx_util.h"
+
+namespace cc {
+namespace {
+
+float diagonal(float width, float height) {
+  return std::sqrt(width * width + height * height);
+}
+
+class LayerUtilsGetAnimationBoundsTest : public testing::Test {
+ public:
+  LayerUtilsGetAnimationBoundsTest()
+      : host_impl_(&proxy_),
+        root_(CreateThreeNodeTree(host_impl_)),
+        parent_(root_->children()[0]),
+        child_(parent_->children()[0]) {}
+
+  LayerImpl* root() { return root_.get(); }
+  LayerImpl* parent() { return parent_; }
+  LayerImpl* child() { return child_; }
+
+ private:
+  static scoped_ptr<LayerImpl> CreateThreeNodeTree(
+      LayerTreeHostImpl& host_impl) {
+    scoped_ptr<LayerImpl> root = LayerImpl::Create(host_impl.active_tree(), 1);
+    root->AddChild(LayerImpl::Create(host_impl.active_tree(), 2));
+    root->children()[0]
+        ->AddChild(LayerImpl::Create(host_impl.active_tree(), 3));
+    return root.Pass();
+  }
+
+  FakeImplProxy proxy_;
+  FakeLayerTreeHostImpl host_impl_;
+  scoped_ptr<LayerImpl> root_;
+  LayerImpl* parent_;
+  LayerImpl* child_;
+};
+
+TEST_F(LayerUtilsGetAnimationBoundsTest, ScaleRoot) {
+  double duration = 1.0;
+
+  TransformOperations start;
+  start.AppendScale(1.f, 1.f, 1.f);
+  TransformOperations end;
+  end.AppendScale(2.f, 2.f, 1.f);
+  AddAnimatedTransformToLayer(root(), duration, start, end);
+
+  root()->SetPosition(gfx::PointF());
+  parent()->SetPosition(gfx::PointF());
+  parent()->SetBounds(gfx::Size(350, 200));
+
+  child()->SetDrawsContent(true);
+  child()->draw_properties().screen_space_transform_is_animating = true;
+  child()->SetPosition(gfx::PointF(150.f, 50.f));
+  child()->SetBounds(gfx::Size(100, 200));
+
+  gfx::BoxF box;
+  bool success = LayerUtils::GetAnimationBounds(*child(), &box);
+  EXPECT_TRUE(success);
+  gfx::BoxF expected(150.f, 50.f, 0.f, 350.f, 450.f, 0.f);
+  EXPECT_BOXF_EQ(expected, box);
+}
+
+TEST_F(LayerUtilsGetAnimationBoundsTest, TranslateParentLayer) {
+  double duration = 1.0;
+
+  TransformOperations start;
+  start.AppendTranslate(0.f, 0.f, 0.f);
+  TransformOperations end;
+  end.AppendTranslate(50.f, 50.f, 0.f);
+  AddAnimatedTransformToLayer(parent(), duration, start, end);
+
+  parent()->SetBounds(gfx::Size(350, 200));
+
+  child()->SetDrawsContent(true);
+  child()->draw_properties().screen_space_transform_is_animating = true;
+  child()->SetPosition(gfx::PointF(150.f, 50.f));
+  child()->SetBounds(gfx::Size(100, 200));
+
+  gfx::BoxF box;
+  bool success = LayerUtils::GetAnimationBounds(*child(), &box);
+  EXPECT_TRUE(success);
+  gfx::BoxF expected(150.f, 50.f, 0.f, 150.f, 250.f, 0.f);
+  EXPECT_BOXF_EQ(expected, box);
+}
+
+TEST_F(LayerUtilsGetAnimationBoundsTest, TranslateChildLayer) {
+  double duration = 1.0;
+
+  TransformOperations start;
+  start.AppendTranslate(0.f, 0.f, 0.f);
+  TransformOperations end;
+  end.AppendTranslate(50.f, 50.f, 0.f);
+  AddAnimatedTransformToLayer(child(), duration, start, end);
+
+  parent()->SetBounds(gfx::Size(350, 200));
+
+  child()->SetDrawsContent(true);
+  child()->draw_properties().screen_space_transform_is_animating = true;
+  child()->SetPosition(gfx::PointF(150.f, 50.f));
+  child()->SetBounds(gfx::Size(100, 200));
+
+  gfx::BoxF box;
+  bool success = LayerUtils::GetAnimationBounds(*child(), &box);
+  EXPECT_TRUE(success);
+  gfx::BoxF expected(150.f, 50.f, 0.f, 150.f, 250.f, 0.f);
+  EXPECT_BOXF_EQ(expected, box);
+}
+
+TEST_F(LayerUtilsGetAnimationBoundsTest, TranslateBothLayers) {
+  double duration = 1.0;
+
+  TransformOperations start;
+  start.AppendTranslate(0.f, 0.f, 0.f);
+  TransformOperations child_end;
+  child_end.AppendTranslate(50.f, 0.f, 0.f);
+  AddAnimatedTransformToLayer(parent(), duration, start, child_end);
+
+  TransformOperations grand_child_end;
+  grand_child_end.AppendTranslate(0.f, 50.f, 0.f);
+  AddAnimatedTransformToLayer(child(), duration, start, grand_child_end);
+
+  parent()->SetBounds(gfx::Size(350, 200));
+
+  child()->SetDrawsContent(true);
+  child()->draw_properties().screen_space_transform_is_animating = true;
+  child()->SetPosition(gfx::PointF(150.f, 50.f));
+  child()->SetBounds(gfx::Size(100, 200));
+
+  gfx::BoxF box;
+  bool success = LayerUtils::GetAnimationBounds(*child(), &box);
+  EXPECT_TRUE(success);
+  gfx::BoxF expected(150.f, 50.f, 0.f, 150.f, 250.f, 0.f);
+  EXPECT_BOXF_EQ(expected, box);
+}
+
+TEST_F(LayerUtilsGetAnimationBoundsTest, RotateXNoPerspective) {
+  double duration = 1.0;
+
+  TransformOperations start;
+  start.AppendRotate(1.f, 0.f, 0.f, 0.f);
+  TransformOperations end;
+  end.AppendRotate(1.f, 0.f, 0.f, 90.f);
+  AddAnimatedTransformToLayer(child(), duration, start, end);
+
+  parent()->SetBounds(gfx::Size(350, 200));
+
+  gfx::Size bounds(100, 100);
+  child()->SetDrawsContent(true);
+  child()->draw_properties().screen_space_transform_is_animating = true;
+  child()->SetPosition(gfx::PointF(150.f, 50.f));
+  child()->SetBounds(bounds);
+
+  gfx::BoxF box;
+  bool success = LayerUtils::GetAnimationBounds(*child(), &box);
+  EXPECT_TRUE(success);
+  gfx::BoxF expected(150.f, 50.f, -50.f, 100.f, 100.f, 100.f);
+  EXPECT_BOXF_EQ(expected, box);
+}
+
+TEST_F(LayerUtilsGetAnimationBoundsTest, RotateXWithPerspective) {
+  double duration = 1.0;
+
+  TransformOperations start;
+  start.AppendRotate(1.f, 0.f, 0.f, 0.f);
+  TransformOperations end;
+  end.AppendRotate(1.f, 0.f, 0.f, 90.f);
+  AddAnimatedTransformToLayer(child(), duration, start, end);
+
+  // Make the anchor point not the default 0.5 value and line up with the
+  // child center to make the math easier.
+  parent()->SetAnchorPoint(gfx::PointF(0.375f, 0.375f));
+  parent()->SetBounds(gfx::Size(400, 400));
+
+  gfx::Transform perspective;
+  perspective.ApplyPerspectiveDepth(100.f);
+  parent()->SetSublayerTransform(perspective);
+
+  gfx::Size bounds(100, 100);
+  child()->SetDrawsContent(true);
+  child()->draw_properties().screen_space_transform_is_animating = true;
+  child()->SetPosition(gfx::PointF(100.f, 100.f));
+  child()->SetBounds(bounds);
+
+  gfx::BoxF box;
+  bool success = LayerUtils::GetAnimationBounds(*child(), &box);
+  EXPECT_TRUE(success);
+  gfx::BoxF expected(50.f, 50.f, -33.333336f, 200.f, 200.f, 133.333344f);
+  EXPECT_BOXF_EQ(expected, box);
+}
+
+TEST_F(LayerUtilsGetAnimationBoundsTest, RotateZ) {
+  double duration = 1.0;
+
+  TransformOperations start;
+  start.AppendRotate(0.f, 0.f, 1.f, 0.f);
+  TransformOperations end;
+  end.AppendRotate(0.f, 0.f, 1.f, 90.f);
+  AddAnimatedTransformToLayer(child(), duration, start, end);
+
+  parent()->SetBounds(gfx::Size(350, 200));
+
+  gfx::Size bounds(100, 100);
+  child()->SetDrawsContent(true);
+  child()->draw_properties().screen_space_transform_is_animating = true;
+  child()->SetPosition(gfx::PointF(150.f, 50.f));
+  child()->SetBounds(bounds);
+
+  gfx::BoxF box;
+  bool success = LayerUtils::GetAnimationBounds(*child(), &box);
+  EXPECT_TRUE(success);
+  float diag = diagonal(bounds.width(), bounds.height());
+  gfx::BoxF expected(150.f + 0.5f * (bounds.width() - diag),
+                     50.f + 0.5f * (bounds.height() - diag),
+                     0.f,
+                     diag,
+                     diag,
+                     0.f);
+  EXPECT_BOXF_EQ(expected, box);
+}
+
+TEST_F(LayerUtilsGetAnimationBoundsTest, MismatchedTransforms) {
+  double duration = 1.0;
+
+  TransformOperations start;
+  start.AppendTranslate(5, 6, 7);
+  TransformOperations end;
+  end.AppendRotate(0.f, 0.f, 1.f, 90.f);
+  AddAnimatedTransformToLayer(child(), duration, start, end);
+
+  parent()->SetBounds(gfx::Size(350, 200));
+
+  gfx::Size bounds(100, 100);
+  child()->SetDrawsContent(true);
+  child()->draw_properties().screen_space_transform_is_animating = true;
+  child()->SetPosition(gfx::PointF(150.f, 50.f));
+  child()->SetBounds(bounds);
+
+  gfx::BoxF box;
+  bool success = LayerUtils::GetAnimationBounds(*child(), &box);
+  EXPECT_FALSE(success);
+}
+
+}  // namespace
+}  // namespace cc