Transform animations should not collapse by default when interpolating

ui/compositor/transform_animation_curve_adapter.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/transform_animation_curve_adapter.h"
 
 #include "base/memory/ptr_util.h"
 #include "cc/base/time_util.h"
 
 namespace ui {
 
+namespace {
+
+static cc::TransformOperations wrapTransform(const gfx::Transform& transform) {

[ajuma, 2017/07/04 14:50:56]

nit: capitalize function name

[Ian Vollick, 2017/07/04 16:15:18]

Done.

+  cc::TransformOperations operations;
+  operations.AppendMatrix(transform);
+  return operations;
+}
+
+}  // namespace
+
 TransformAnimationCurveAdapter::TransformAnimationCurveAdapter(
     gfx::Tween::Type tween_type,
     gfx::Transform initial_value,
     gfx::Transform target_value,
     base::TimeDelta duration)
     : tween_type_(tween_type),
       initial_value_(initial_value),
       target_value_(target_value),

[ajuma, 2017/07/04 14:50:56]

If we call WrapTransform here so the stored intial_value_ and target_value_ are
TransformOperations, we save having to call WrapTransform on every call to
::GetValue.

[Ian Vollick, 2017/07/04 16:15:18]

Done.

       duration_(duration) {
   gfx::DecomposeTransform(&decomposed_initial_value_, initial_value_);
   gfx::DecomposeTransform(&decomposed_target_value_, target_value_);
 }
 
 TransformAnimationCurveAdapter::TransformAnimationCurveAdapter(
     const TransformAnimationCurveAdapter& other) = default;
 
 TransformAnimationCurveAdapter::~TransformAnimationCurveAdapter() {
 }
 
 base::TimeDelta TransformAnimationCurveAdapter::Duration() const {
   return duration_;
 }
 
 std::unique_ptr<cc::AnimationCurve> TransformAnimationCurveAdapter::Clone()
     const {
   return base::WrapUnique(new TransformAnimationCurveAdapter(
       tween_type_, initial_value_, target_value_, duration_));
 }
 
-gfx::Transform TransformAnimationCurveAdapter::GetValue(
+cc::TransformOperations TransformAnimationCurveAdapter::GetValue(
     base::TimeDelta t) const {
   if (t >= duration_)
-    return target_value_;
+    return wrapTransform(target_value_);
   if (t <= base::TimeDelta())
-    return initial_value_;
+    return wrapTransform(initial_value_);
   double progress = cc::TimeUtil::Divide(t, duration_);
 
   gfx::DecomposedTransform to_return = gfx::BlendDecomposedTransforms(
       decomposed_target_value_, decomposed_initial_value_,
       gfx::Tween::CalculateValue(tween_type_, progress));
-  return gfx::ComposeTransform(to_return);
+
+  return wrapTransform(gfx::ComposeTransform(to_return));
 }
 
 bool TransformAnimationCurveAdapter::AnimatedBoundsForBox(
     const gfx::BoxF& box,
     gfx::BoxF* bounds) const {
   // TODO(ajuma): Once cc::TransformOperation::BlendedBoundsForBox supports
   // computing bounds for TransformOperationMatrix, use that to compute
   // the bounds we need here.
   return false;
 }
@@ skipping 22 matching lines @@
 }
 
 InverseTransformCurveAdapter::InverseTransformCurveAdapter(
     TransformAnimationCurveAdapter base_curve,
     gfx::Transform initial_value,
     base::TimeDelta duration)
     : base_curve_(base_curve),
       initial_value_(initial_value),
       duration_(duration) {
   effective_initial_value_ =
-      base_curve_.GetValue(base::TimeDelta()) * initial_value_;
+      base_curve_.GetValue(base::TimeDelta()).Apply() * initial_value_;
 }
 
 InverseTransformCurveAdapter::~InverseTransformCurveAdapter() {
 }
 
 base::TimeDelta InverseTransformCurveAdapter::Duration() const {
   return duration_;
 }
 
 std::unique_ptr<cc::AnimationCurve> InverseTransformCurveAdapter::Clone()
     const {
   return base::WrapUnique(
       new InverseTransformCurveAdapter(base_curve_, initial_value_, duration_));
 }
 
-gfx::Transform InverseTransformCurveAdapter::GetValue(base::TimeDelta t) const {
+cc::TransformOperations InverseTransformCurveAdapter::GetValue(
+    base::TimeDelta t) const {
   if (t <= base::TimeDelta())
-    return initial_value_;
+    return wrapTransform(initial_value_);
 
-  gfx::Transform base_transform = base_curve_.GetValue(t);
+  gfx::Transform base_transform = base_curve_.GetValue(t).Apply();
   // Invert base
   gfx::Transform to_return(gfx::Transform::kSkipInitialization);
   bool is_invertible = base_transform.GetInverse(&to_return);
   DCHECK(is_invertible);
 
   to_return.PreconcatTransform(effective_initial_value_);
-  return to_return;
+
+  return wrapTransform(to_return);
 }
 
 bool InverseTransformCurveAdapter::AnimatedBoundsForBox(
     const gfx::BoxF& box,
     gfx::BoxF* bounds) const {
   // TODO(ajuma): Once cc::TransformOperation::BlendedBoundsForBox supports
   // computing bounds for TransformOperationMatrix, use that to compute
   // the bounds we need here.
   return false;
 }
@@ skipping 14 matching lines @@
     float* start_scale) const {
   return false;
 }
 
 bool InverseTransformCurveAdapter::MaximumTargetScale(bool forward_direction,
                                                       float* max_scale) const {
   return false;
 }
 
 }  // namespace ui