Implemented screen rotation animation experiment.

ash/rotator/screen_rotation_animator.cc

Index: ash/rotator/screen_rotation_animator.cc
diff --git a/ash/rotator/screen_rotation_animator.cc b/ash/rotator/screen_rotation_animator.cc
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index 0000000000000000000000000000000000000000..9568890b33d630c262a6a947eae673d8be4ece9d
--- /dev/null
+++ b/ash/rotator/screen_rotation_animator.cc
@@ -0,0 +1,329 @@
+// Copyright 2015 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 "ash/rotator/screen_rotation_animator.h"
+
+#include <string>
+#include <vector>
+
+#include "ash/ash_switches.h"
+#include "ash/display/display_controller.h"
+#include "ash/display/display_info.h"
+#include "ash/display/display_manager.h"
+#include "ash/rotator/screen_rotation_animation.h"
+#include "ash/shell.h"
+#include "base/command_line.h"
+#include "base/time/time.h"
+#include "ui/aura/window.h"
+#include "ui/compositor/layer.h"
+#include "ui/compositor/layer_animation_observer.h"
+#include "ui/compositor/layer_animation_sequence.h"
+#include "ui/compositor/layer_animator.h"
+#include "ui/compositor/layer_owner.h"
+#include "ui/compositor/layer_tree_owner.h"
+#include "ui/gfx/animation/tween.h"
+#include "ui/gfx/display.h"
+#include "ui/gfx/geometry/point.h"
+#include "ui/gfx/geometry/rect.h"
+#include "ui/gfx/geometry/rect_f.h"
+#include "ui/gfx/transform.h"
+#include "ui/gfx/transform_util.h"
+
+namespace ash {
+
+namespace {
+
+// The number of degrees the partial rotation animations animate through.
+const int kPartialRotationDegrees = 20;
+
+// The time it takes for the normal speed rotation animations to run.
+const int kRotationDurationInMs = 250;
+
+// The time it takes for the slow speed rotation animations to run.
+const int kRotationDurationSlowInMs = 2500;
+
+// Clones all child layers of |to_clone| and adds the clones as children to
+// |parent|. Recurses on each child of |to_clone|.
+void CloneChildren(ui::Layer* to_clone, ui::Layer* parent) {
+  typedef std::vector<ui::Layer*> Layers;
+  // Make a copy of the children since RecreateLayer() mutates it.
+  Layers children(to_clone->children());
+  for (Layers::const_iterator i = children.begin(); i != children.end(); ++i) {
+    ui::LayerOwner* owner = (*i)->owner();
+    ui::Layer* clone = owner ? owner->RecreateLayer().release() : NULL;
+    if (clone) {
+      parent->Add(clone);
+      // RecreateLayer() moves the existing children to the new layer. Create a
+      // copy of those.
+      CloneChildren(owner->layer(), clone);
+    }
+  }
+}
+
+// Clones the layer tree owned by |window| and adds the cloned layer tree as a
+// child of |window|'s layer.
+scoped_ptr<ui::LayerTreeOwner> CloneWindowLayers(aura::Window* window) {

[oshima, 2015/03/04 21:31:35]

Can you use wm::RecreateLayers in ui/wm/core/window_util.h?

[bruthig, 2015/03/06 16:00:33]

Not with the current implementation of wm::RecreateLayers.  However I have a fix
in review for it here: https://codereview.chromium.org/983933002/
I have included the fix in this review but will not submit until the other CL
lands.

+  scoped_ptr<ui::LayerTreeOwner> cloned_layer_tree(
+      new ui::LayerTreeOwner(new ui::Layer()));
+  CloneChildren(window->layer(), cloned_layer_tree->root());
+
+  DCHECK(cloned_layer_tree->root());
+  DCHECK(window->layer());
+
+  // Add the cloned layer tree into the root, so it will be rendered.
+  window->layer()->Add(cloned_layer_tree->root());
+  window->layer()->StackAtTop(cloned_layer_tree->root());
+
+  return cloned_layer_tree.Pass();
+}
+
+// Gets the current display rotation for the display with the specified
+// |display_id|.
+gfx::Display::Rotation GetCurrentRotation(int64 display_id) {
+  return Shell::GetInstance()
+      ->display_manager()
+      ->GetDisplayInfo(display_id)
+      .rotation();
+}
+
+// Returns true if the rotation between |initial_rotation| and |new_rotation| is
+// 180 degrees.
+bool Is180DegreeFlip(gfx::Display::Rotation initial_rotation,
+                     gfx::Display::Rotation new_rotation) {
+  return (initial_rotation + 2) % 4 == new_rotation;
+}
+
+// A LayerAnimationObserver that will destroy the contained LayerTreeOwner when
+// notified that a layer animation has ended or was aborted.
+class LayerCleanupObserver : public ui::LayerAnimationObserver {
+ public:
+  explicit LayerCleanupObserver(
+      scoped_ptr<ui::LayerTreeOwner> layer_tree_owner);
+  ~LayerCleanupObserver() override;
+
+  // Get the root layer of the owned layer tree.
+  ui::Layer* GetRootLayer();
+
+  // ui::LayerAnimationObserver:
+  void OnLayerAnimationEnded(ui::LayerAnimationSequence* sequence) override;
+  void OnLayerAnimationAborted(ui::LayerAnimationSequence* sequence) override;
+  void OnLayerAnimationScheduled(
+      ui::LayerAnimationSequence* sequence) override {}
+
+ protected:
+  // ui::LayerAnimationObserver:
+  bool RequiresNotificationWhenAnimatorDestroyed() const override {
+    return true;
+  }
+  void OnAttachedToSequence(ui::LayerAnimationSequence* sequence) override;
+  void OnDetachedFromSequence(ui::LayerAnimationSequence* sequence) override;
+
+ private:
+  // The owned layer tree.
+  scoped_ptr<ui::LayerTreeOwner> layer_tree_owner_;
+
+  // The LayerAnimationSequence that |this| has been attached to. Defaults to
+  // nullptr.
+  ui::LayerAnimationSequence* sequence_;
+
+  DISALLOW_COPY_AND_ASSIGN(LayerCleanupObserver);
+};
+
+LayerCleanupObserver::LayerCleanupObserver(
+    scoped_ptr<ui::LayerTreeOwner> layer_tree_owner)
+    : layer_tree_owner_(layer_tree_owner.Pass()), sequence_(nullptr) {
+}
+
+LayerCleanupObserver::~LayerCleanupObserver() {
+  // We must eplicitly detach from |sequence_| because we return true from
+  // RequiresNotificationWhenAnimatorDestroyed.
+  if (sequence_)
+    sequence_->RemoveObserver(this);
+}
+
+ui::Layer* LayerCleanupObserver::GetRootLayer() {
+  return layer_tree_owner_->root();
+}
+
+void LayerCleanupObserver::OnLayerAnimationEnded(
+    ui::LayerAnimationSequence* sequence) {
+  delete this;
+}
+
+void LayerCleanupObserver::OnLayerAnimationAborted(
+    ui::LayerAnimationSequence* sequence) {
+  delete this;
+}
+
+void LayerCleanupObserver::OnAttachedToSequence(
+    ui::LayerAnimationSequence* sequence) {
+  sequence_ = sequence;
+}
+
+void LayerCleanupObserver::OnDetachedFromSequence(
+    ui::LayerAnimationSequence* sequence) {
+  DCHECK(sequence == sequence_);
+  sequence_ = nullptr;
+}
+
+// Set the screen orientation for the given |display| to |new_rotation| and
+// animate the change.
+void RotateScreen(gfx::Display display,
+                  gfx::Display::Rotation new_rotation,
+                  base::TimeDelta duration,
+                  int rotation_degrees,
+                  int rotation_degree_offset,
+                  gfx::Tween::Type tween_type,
+                  bool should_scale) {
+  aura::Window* root_window =
+      Shell::GetInstance()->display_controller()->GetRootWindowForDisplayId(
+          display.id());
+
+  const gfx::RectF original_screen_bounds = root_window->GetTargetBounds();

[oshima, 2015/03/04 21:31:35]

What happens if the root window is destroyed while animating?

[bruthig, 2015/03/06 16:00:33]

As best I can tell, the RootWindow will complete all animations on it's layer
which will recursively complete all animations on child layers.  This should
cause the LayerCleanupObserver to cleanup before anything else is destroyed.

+  // 180 degree rotations should animation clock-wise.
+  const int rotation_factor =
+      (GetCurrentRotation(display.id()) + 3) % 4 == new_rotation ? 1 : -1;
+  scoped_ptr<LayerCleanupObserver> layer_cleanup_observer(
+      new LayerCleanupObserver(CloneWindowLayers(root_window).Pass()));
+
+  Shell::GetInstance()->display_manager()->SetDisplayRotation(display.id(),
+                                                              new_rotation);
+
+  const gfx::RectF rotated_screen_bounds = root_window->GetTargetBounds();
+  const gfx::Point pivot =
+      Is180DegreeFlip(GetCurrentRotation(display.id()), new_rotation)
+          ? gfx::Point(rotated_screen_bounds.height() / 2,
+                       rotated_screen_bounds.width() / 2)
+          : gfx::Point(rotated_screen_bounds.width() / 2,
+                       rotated_screen_bounds.height() / 2);
+
+  gfx::Point3F new_layer_initial_scale = gfx::Point3F(1.0f, 1.0f, 1.0f);
+  gfx::Point3F old_layer_target_scale = gfx::Point3F(1.0f, 1.0f, 1.0f);
+
+  if (should_scale) {
+    new_layer_initial_scale = gfx::Point3F(
+        original_screen_bounds.width() / rotated_screen_bounds.width(),
+        original_screen_bounds.height() / rotated_screen_bounds.height(), 1.0f);
+
+    old_layer_target_scale = gfx::Point3F(
+        rotated_screen_bounds.width() / original_screen_bounds.width(),
+        rotated_screen_bounds.height() / original_screen_bounds.height(), 1.0f);
+  }
+
+  // We must animate each non-cloned child layer individually because the cloned
+  // layer was added as a child to |root_window|'s layer so that it will be
+  // rendered.
+  for (ui::Layer* child_layer : root_window->layer()->children()) {
+    // Skip the cloned layer because it has a different animation.
+    if (child_layer == layer_cleanup_observer->GetRootLayer())
+      continue;
+
+    scoped_ptr<ScreenRotationAnimation> screen_rotation(
+        new ScreenRotationAnimation(
+            child_layer, rotation_degrees * rotation_factor,
+            0 /* end_degrees */, new_layer_initial_scale,
+            gfx::Point3F(1.0f, 1.0f, 1.0f), pivot, duration));
+
+    screen_rotation->set_tween_type(tween_type);
+    screen_rotation->set_target_opacity(1.0f);
+
+    ui::LayerAnimator* animator = child_layer->GetAnimator();
+    animator->set_preemption_strategy(
+        ui::LayerAnimator::REPLACE_QUEUED_ANIMATIONS);
+    scoped_ptr<ui::LayerAnimationSequence> animation_sequence(
+        new ui::LayerAnimationSequence(screen_rotation.release()));
+    animator->StartAnimation(animation_sequence.release());
+  }
+
+  // The old layer will also be transformed into the new orientation. We will
+  // translate it so that the old layer's center point aligns with the new
+  // orientation's center point and use that center point as the pivot for the
+  // rotation animation.
+  gfx::Transform translate_transform =
+      layer_cleanup_observer->GetRootLayer()->GetTargetTransform();
+  translate_transform.Translate(
+      (rotated_screen_bounds.width() - original_screen_bounds.width()) / 2,
+      (rotated_screen_bounds.height() - original_screen_bounds.height()) / 2);
+  layer_cleanup_observer->GetRootLayer()->SetTransform(translate_transform);
+
+  scoped_ptr<ScreenRotationAnimation> screen_rotation(
+      new ScreenRotationAnimation(
+          layer_cleanup_observer->GetRootLayer(),
+          (rotation_degrees + rotation_degree_offset) * rotation_factor,
+          rotation_degree_offset * rotation_factor,
+          gfx::Point3F(1.0f, 1.0f, 1.0f), old_layer_target_scale, pivot,
+          duration));
+
+  screen_rotation->set_tween_type(tween_type);
+  screen_rotation->set_target_opacity(0.0f);
+
+  ui::LayerAnimator* animator =
+      layer_cleanup_observer->GetRootLayer()->GetAnimator();
+  animator->set_preemption_strategy(
+      ui::LayerAnimator::REPLACE_QUEUED_ANIMATIONS);
+  scoped_ptr<ui::LayerAnimationSequence> animation_sequence(
+      new ui::LayerAnimationSequence(screen_rotation.release()));
+  // Add an observer so that the cloned layers can be cleaned up with the
+  // animation completes/aborts.
+  animation_sequence->AddObserver(layer_cleanup_observer.release());
+  animator->StartAnimation(animation_sequence.release());
+}
+
+}  // namespace
+
+ScreenRotationAnimator::ScreenRotationAnimator(int64 display_id)
+    : display_(Shell::GetInstance()->display_manager()->GetDisplayForId(
+          display_id)) {
+}
+
+ScreenRotationAnimator::ScreenRotationAnimator(gfx::Display display)
+    : display_(display) {
+}
+
+ScreenRotationAnimator::~ScreenRotationAnimator() {
+}
+
+void ScreenRotationAnimator::Rotate(gfx::Display::Rotation new_rotation) {
+  const gfx::Display::Rotation current_rotation =
+      GetCurrentRotation(display_.id());
+
+  if (current_rotation == new_rotation)
+    return;
+
+  const std::string switch_value =
+      base::CommandLine::ForCurrentProcess()->GetSwitchValueASCII(
+          switches::kAshEnableScreenRotationAnimation);
+
+  if ("" == switch_value) {

[oshima, 2015/03/04 21:31:35]

switch_value.empty()

[bruthig, 2015/03/06 16:00:33]

Done.

+    Shell::GetInstance()->display_manager()->SetDisplayRotation(display_.id(),
+                                                                new_rotation);
+    return;
+  }
+
+  if ("partial-rotation" == switch_value ||
+      "partial-rotation-slow" == switch_value) {

[oshima, 2015/03/04 21:31:35]

can you define const with the comments that explains how they differ?

[bruthig, 2015/03/06 16:00:33]

Done.

+    RotateScreen(
+        display_, new_rotation,
+        base::TimeDelta::FromMilliseconds("partial-rotation" == switch_value
+                                              ? kRotationDurationInMs
+                                              : kRotationDurationSlowInMs),
+        kPartialRotationDegrees, Is180DegreeFlip(current_rotation, new_rotation)
+                                     ? 180 - kPartialRotationDegrees
+                                     : 90 - kPartialRotationDegrees,

[oshima, 2015/03/04 21:31:35]

can you move this out of constructor to make this easier to read?

[bruthig, 2015/03/06 16:00:33]

Done.

+        gfx::Tween::FAST_OUT_LINEAR_IN, false /* should_scale */);
+  } else if ("full-rotation" == switch_value ||
+             "full-rotation-slow" == switch_value) {
+    RotateScreen(display_, new_rotation, base::TimeDelta::FromMilliseconds(
+                                             "full-rotation" == switch_value
+                                                 ? kRotationDurationInMs
+                                                 : kRotationDurationSlowInMs),

[oshima, 2015/03/04 21:31:35]

ditto

[bruthig, 2015/03/06 16:00:33]

Done.

+                 Is180DegreeFlip(current_rotation, new_rotation) ? 180 : 90,
+                 0 /* rotation_degree_offset */, gfx::Tween::FAST_OUT_LINEAR_IN,
+                 true /* should_scale */);
+  } else {
+    DCHECK(false);

[oshima, 2015/03/04 21:31:35]

NOTREACHED()

[bruthig, 2015/03/06 16:00:33]

Done.

+  }
+}
+
+}  // namespace ash