Explicit animation support

ui/gfx/compositor/layer_animator.h

 // Copyright (c) 2011 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 UI_GFX_COMPOSITOR_LAYER_ANIMATOR_H_
 #define UI_GFX_COMPOSITOR_LAYER_ANIMATOR_H_
 #pragma once
 
-#include <map>
+#include <deque>
+#include <vector>
 
-#include "base/basictypes.h"
-#include "base/compiler_specific.h"
+#include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
-#include "third_party/skia/include/core/SkScalar.h"
-#include "third_party/skia/include/utils/SkMatrix44.h"
-#include "ui/base/animation/animation_delegate.h"
+#include "base/time.h"
 #include "ui/gfx/compositor/compositor_export.h"
+#include "ui/gfx/compositor/layer_animation_element.h"
 
 namespace gfx {
-class Point;
+class Rect;
 }
 
 namespace ui {
-
 class Animation;
 class Layer;
-class LayerAnimatorDelegate;
+class LayerAnimationPreemptionStrategy;
+class LayerAnimationSequence;
 class Transform;
 
-// LayerAnimator manages animating various properties of a Layer.
-class COMPOSITOR_EXPORT LayerAnimator : public ui::AnimationDelegate {
+// When a property of layer needs to be changed it is set by way of
+// LayerAnimator. This enables LayerAnimator to animate property
+// changes.
+class COMPOSITOR_EXPORT LayerAnimator {
  public:
-  // Types of properties that can be animated.
-  enum AnimationProperty {
-    LOCATION,
-    OPACITY,
-    TRANSFORM,
+  // We need to keep track of the start time of every running animation.
+  struct RunningAnimation {
+    RunningAnimation(LayerAnimationSequence* sequence,
+                     base::TimeTicks start_time)
+        : sequence(sequence),
+          start_time(start_time) {
+    }
+    LayerAnimationSequence* sequence;
+    base::TimeTicks start_time;
   };
+  typedef std::vector<RunningAnimation> RunningAnimations;
+  typedef std::deque<scoped_refptr<LayerAnimationSequence> > AnimationQueue;
 
-  explicit LayerAnimator(Layer* layer);
+  // No implicit animations when properties are set.
+  static LayerAnimator* CreateDefaultAnimator();
+
+  // Implicitly animates when properties are set.
+  static LayerAnimator* CreateImplicitAnimator();
+
+  explicit LayerAnimator(base::TimeDelta transition_duration);
   virtual ~LayerAnimator();
 
-  // Sets the animation to use. LayerAnimator takes ownership of the animation.
-  void SetAnimation(Animation* animation);
+  // Sets the transform on the Layer.
+  virtual void SetTransform(const Transform& transform);
 
-  ui::Layer* layer() { return layer_; }
+  // Sets the bounds of the layer.
+  virtual void SetBounds(const gfx::Rect& bounds);
 
-  // Animates the layer to the specified point. The point is relative to the
-  // parent layer.
-  void AnimateToPoint(const gfx::Point& target);
+  // Sets the opacity of the layer.
+  virtual void SetOpacity(float opacity);
 
-  // Animates the transform from the current transform to |transform|.
-  void AnimateTransform(const Transform& transform);
+  // Sets the layer the property setter is associated with. The property setter
+  // does not own the layer and can only be associated with a single layer.
+  void SetLayer(Layer* layer);
 
-  // Animates the opacity from the current opacity to |target_opacity|.
-  void AnimateOpacity(float target_opacity);
+  // Sets the animation preemption strategy. This determines the behaviour if
+  // a property is set during an animation. This class does not own the
+  // strategy.
+  void set_preemption_strategy(LayerAnimationPreemptionStrategy* strategy) {
+    preemption_strategy_ = strategy;
+  }
 
-  // Returns the target value for the specified type. If the specified property
-  // is not animating, the current value is returned.
-  gfx::Point GetTargetPoint();
-  float GetTargetOpacity();
-  ui::Transform GetTargetTransform();
+  // Set an animation sequence. If an animation for the same property is in
+  // progress, it needs to be interrupted with the new animation.
+  void SetAnimation(LayerAnimationSequence* animation);

[sky, 2011/10/14 16:39:52]

The name 'Set' implies you can only have one. How about Replace.

 
-  // Returns true if animating |property|.
-  bool IsAnimating(AnimationProperty property) const;
+  // Enqueue an animation
+  void EnqueueAnimation(LayerAnimationSequence* animation);

[sky, 2011/10/14 16:39:52]

How about Add.

 
-  // Returns true if the animation is running.
-  bool IsRunning() const;
+  // Returns true if there is an animation in the queue (animations remain in
+  // the queue until they complete).
+  bool IsAnimating() const;
 
-  // Returns true if the animation has progressed at least once since
-  // SetAnimation() was invoked.
-  bool got_initial_tick() const { return got_initial_tick_; }
+  // Stops animating the given property. No effect if there is no running
+  // animation for the given property.
+  void StopAnimatingProperty(
+      LayerAnimationElement::AnimatableProperty property);
 
-  // AnimationDelegate:
-  virtual void AnimationProgressed(const Animation* animation) OVERRIDE;
-  virtual void AnimationEnded(const Animation* animation) OVERRIDE;
+  // Stops all animation and clears any queued animations.
+  void StopAnimating();
+
+  void Step(base::TimeTicks now);
+
+ protected:
+  Layer* layer() { return layer_; }
 
  private:
-  // Parameters used when animating the location.
-  struct LocationParams {
-    int start_x;
-    int start_y;
-    int target_x;
-    int target_y;
-  };
+  void UpdateAnimationState();
+  void RemoveAnimation(LayerAnimationSequence* sequence);
+  void FinishAnimation(LayerAnimationSequence* sequence);
+  void FinishAnyAnimationWithZeroDuration();
+  void ClearAnimations();
+  RunningAnimation* GetRunningAnimation(
+      LayerAnimationElement::AnimatableProperty property);
+  void AddToQueueIfNotPresent(LayerAnimationSequence* sequence);
+  void ProcessQueue();
+  bool StartSequence(LayerAnimationSequence* sequence);
 
-  // Parameters used when animating the transform.
-  struct TransformParams {
-    SkMScalar start[16];
-    SkMScalar target[16];
-  };
+  // This is the queue of animations to run
+  AnimationQueue animation_queue_;
 
-  // Parameters used when animating the opacity.
-  struct OpacityParams {
-    float start;
-    float target;
-  };
-
-  union Params {
-    LocationParams location;
-    OpacityParams opacity;
-    TransformParams transform;
-  };
-
-  typedef std::map<AnimationProperty, Params> Elements;
-
-  // Stops animating the specified property. This does not set the property
-  // being animated to its final value.
-  void StopAnimating(AnimationProperty property);
-
-  LayerAnimatorDelegate* delegate();
-
-  // The layer.
+  // The target of all layer animations
   Layer* layer_;
 
-  // Properties being animated.
-  Elements elements_;
+  // The currently running animations
+  RunningAnimations running_animations_;
 
-  scoped_ptr<ui::Animation> animation_;
+  // Determines how animations are replaced.
+  LayerAnimationPreemptionStrategy* preemption_strategy_;
 
-  bool got_initial_tick_;
+  // The default length of animations.
+  base::TimeDelta transition_duration_;
+
+  // Drives the animations
+  scoped_ptr<Animation> animation_;
 
   DISALLOW_COPY_AND_ASSIGN(LayerAnimator);
 };
 
 }  // namespace ui
 
 #endif  // UI_GFX_COMPOSITOR_LAYER_ANIMATOR_H_