Add support for inverse transform animations.

ui/compositor/layer_animation_element_unittest.cc

 // Copyright (c) 2012 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 "ui/compositor/layer_animation_element.h"
 
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/time/time.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "ui/compositor/layer_animation_delegate.h"
 #include "ui/compositor/test/test_layer_animation_delegate.h"
 #include "ui/compositor/test/test_utils.h"
 #include "ui/gfx/rect.h"
 #include "ui/gfx/transform.h"
 
 namespace ui {
 
 namespace {
 
 // Check that the transformation element progresses the delegate as expected and
 // that the element can be reused after it completes.
 TEST(LayerAnimationElementTest, TransformElement) {
   TestLayerAnimationDelegate delegate;
-  gfx::Transform start_transform, target_transform, middle_transform;
+  gfx::Transform start_transform, target_transform;
   start_transform.Rotate(-30.0);
   target_transform.Rotate(30.0);
   base::TimeTicks start_time;
   base::TimeTicks effective_start_time;
   base::TimeDelta delta = base::TimeDelta::FromSeconds(1);
 
   scoped_ptr<LayerAnimationElement> element(
       LayerAnimationElement::CreateTransformElement(target_transform, delta));
   element->set_animation_group_id(1);
 
@@ skipping 21 matching lines @@
     EXPECT_FLOAT_EQ(1.0, element->last_progressed_fraction());
     CheckApproximatelyEqual(target_transform,
                             delegate.GetTransformForAnimation());
   }
 
   LayerAnimationElement::TargetValue target_value(&delegate);
   element->GetTargetValue(&target_value);
   CheckApproximatelyEqual(target_transform, target_value.transform);
 }
 
+// Checks that the equation Child_start * Parent_start = Child_current *
+// Parent_current is true.
+TEST(LayerAnimationElementTest, CounterTransformElement) {
+  TestLayerAnimationDelegate delegate, parent_delegate;
+  gfx::Transform parent_start, parent_target;
+  parent_start.Scale(0.5, 3);
+  parent_start.Translate(-20, 30);
+  parent_target.Translate(0, 100);
+
+  gfx::Transform child_transform;
+  child_transform.Rotate(-30.0);
+
+  const gfx::Transform effective_child_transform =
+      child_transform * parent_start;
+
+  base::TimeTicks start_time;
+  base::TimeTicks now;
+  base::TimeDelta duration = base::TimeDelta::FromSeconds(1);
+
+  start_time += 5 * duration;
+  scoped_ptr<LayerAnimationElement> element(
+      LayerAnimationElement::CreateInverseTransformElement(parent_start,
+                                                           parent_target,
+                                                           duration));
+  element->set_animation_group_id(1);
+  scoped_ptr<LayerAnimationElement> parent_element(
+      LayerAnimationElement::CreateTransformElement(parent_target, duration));
+
+  parent_delegate.SetTransformFromAnimation(parent_start);
+  delegate.SetTransformFromAnimation(child_transform);
+
+  parent_element->set_requested_start_time(start_time);
+  parent_element->Start(&parent_delegate, 1);
+  parent_element->set_effective_start_time(start_time);
+  parent_element->Progress(start_time, &parent_delegate);
+
+  element->set_requested_start_time(start_time);
+  element->Start(&delegate, 1);
+  element->set_effective_start_time(start_time);
+  element->Progress(start_time, &delegate);
+  CheckApproximatelyEqual(effective_child_transform,
+                          delegate.GetTransformForAnimation() *
+                          parent_delegate.GetTransformForAnimation());
+  const int steps = 1000;
+  now = start_time;
+  for (int i = 0; i != steps; ++i) {
+    now += duration/steps;
+    parent_element->Progress(start_time, &parent_delegate);
+    element->Progress(start_time, &delegate);
+    CheckApproximatelyEqual(effective_child_transform,
+                            delegate.GetTransformForAnimation() *

[ajuma, 2013/08/20 15:32:41]

For threaded animations, the delegate won't actually get updated as the
animation progresses in LayerAnimationElementTests (since we don't actually have
a compositor). So these are going to be stuck at their initial value. Consider
checking the math by directly instantiating the corresponding
TransformAnimationCurveAdapters and calling GetValue on them.

[avallee, 2013/08/22 22:21:59]

Moved this test to a new test file for the transform curve adapters.

Would it still make sense to simulate an animation here?

+                            parent_delegate.GetTransformForAnimation());
+  }
+}
+
 // Check that the bounds element progresses the delegate as expected and
 // that the element can be reused after it completes.
 TEST(LayerAnimationElementTest, BoundsElement) {
   TestLayerAnimationDelegate delegate;
   gfx::Rect start, target, middle;
   start = target = middle = gfx::Rect(0, 0, 50, 50);
   start.set_x(-90);
   target.set_x(90);
   base::TimeTicks start_time;
   base::TimeDelta delta = base::TimeDelta::FromSeconds(1);
@@ skipping 287 matching lines @@
   element->Abort(&delegate);
   target_transform.Blend(start_transform,
                          Tween::CalculateValue(tween_type, 0.5));
   CheckApproximatelyEqual(target_transform,
                           delegate.GetTransformForAnimation());
 }
 
 } // namespace
 
 } // namespace ui