cc/animation/animation.h

// Copyright 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.

#ifndef CC_ANIMATION_ANIMATION_H_
#define CC_ANIMATION_ANIMATION_H_

#include <memory>

#include "base/macros.h"
#include "base/time/time.h"
#include "cc/animation/target_property.h"
#include "cc/base/cc_export.h"

namespace cc {

class AnimationCurve;

// An Animation contains all the state required to play an AnimationCurve.
// Specifically, the affected property, the run state (paused, finished, etc.),
// loop count, last pause time, and the total time spent paused.
class CC_EXPORT Animation {
 public:
  // Animations begin in the 'WAITING_FOR_TARGET_AVAILABILITY' state. An
  // Animation waiting for target availibility will run as soon as its target
  // property is free (and all the animations animating with it are also able to
  // run). When this time arrives, the controller will move the animation into
  // the STARTING state, and then into the RUNNING state. RUNNING animations may
  // toggle between RUNNING and PAUSED, and may be stopped by moving into either
  // the ABORTED or FINISHED states. A FINISHED animation was allowed to run to
  // completion, but an ABORTED animation was not. An animation in the state
  // ABORTED_BUT_NEEDS_COMPLETION is an animation that was aborted for
  // some reason, but needs to be finished. Currently this is for impl-only
  // scroll offset animations that need to be completed on the main thread.
  enum RunState {
    WAITING_FOR_TARGET_AVAILABILITY = 0,
    WAITING_FOR_DELETION,
    STARTING,
    RUNNING,
    PAUSED,
    FINISHED,
    ABORTED,
    ABORTED_BUT_NEEDS_COMPLETION,
    // This sentinel must be last.
    LAST_RUN_STATE = ABORTED_BUT_NEEDS_COMPLETION
  };

  enum class Direction { NORMAL, REVERSE, ALTERNATE_NORMAL, ALTERNATE_REVERSE };

  enum class FillMode { NONE, FORWARDS, BACKWARDS, BOTH };

  static std::unique_ptr<Animation> Create(
      std::unique_ptr<AnimationCurve> curve,
      int animation_id,
      int group_id,
      TargetProperty::Type target_property);

  virtual ~Animation();

  int id() const { return id_; }
  int group() const { return group_; }
  TargetProperty::Type target_property() const { return target_property_; }

  RunState run_state() const { return run_state_; }
  void SetRunState(RunState run_state, base::TimeTicks monotonic_time);

  // This is the number of times that the animation will play. If this
  // value is zero the animation will not play. If it is negative, then
  // the animation will loop indefinitely.
  double iterations() const { return iterations_; }
  void set_iterations(double n) { iterations_ = n; }

  double iteration_start() const { return iteration_start_; }
  void set_iteration_start(double iteration_start) {
    iteration_start_ = iteration_start;
  }

  base::TimeTicks start_time() const { return start_time_; }

  void set_start_time(base::TimeTicks monotonic_time) {
    start_time_ = monotonic_time;
  }
  bool has_set_start_time() const { return !start_time_.is_null(); }

  base::TimeDelta time_offset() const { return time_offset_; }
  void set_time_offset(base::TimeDelta monotonic_time) {
    time_offset_ = monotonic_time;
  }

  void Suspend(base::TimeTicks monotonic_time);
  void Resume(base::TimeTicks monotonic_time);

  Direction direction() { return direction_; }
  void set_direction(Direction direction) { direction_ = direction; }

  FillMode fill_mode() { return fill_mode_; }
  void set_fill_mode(FillMode fill_mode) { fill_mode_ = fill_mode; }

  double playback_rate() { return playback_rate_; }
  void set_playback_rate(double playback_rate) {
    playback_rate_ = playback_rate;
  }

  bool IsFinishedAt(base::TimeTicks monotonic_time) const;
  bool is_finished() const {
    return run_state_ == FINISHED || run_state_ == ABORTED ||
           run_state_ == WAITING_FOR_DELETION;
  }

  bool InEffect(base::TimeTicks monotonic_time) const;

  AnimationCurve* curve() { return curve_.get(); }
  const AnimationCurve* curve() const { return curve_.get(); }

  // If this is true, even if the animation is running, it will not be tickable
  // until it is given a start time. This is true for animations running on the
  // main thread.
  bool needs_synchronized_start_time() const {
    return needs_synchronized_start_time_;
  }
  void set_needs_synchronized_start_time(bool needs_synchronized_start_time) {
    needs_synchronized_start_time_ = needs_synchronized_start_time;
  }

  // This is true for animations running on the main thread when the FINISHED
  // event sent by the corresponding impl animation has been received.
  bool received_finished_event() const {
    return received_finished_event_;
  }
  void set_received_finished_event(bool received_finished_event) {
    received_finished_event_ = received_finished_event;
  }

  // Takes the given absolute time, and using the start time and the number
  // of iterations, returns the relative time in the current iteration.
  base::TimeDelta TrimTimeToCurrentIteration(
      base::TimeTicks monotonic_time) const;

  std::unique_ptr<Animation> CloneAndInitialize(
      RunState initial_run_state) const;

  void set_is_controlling_instance_for_test(bool is_controlling_instance) {
    is_controlling_instance_ = is_controlling_instance;
  }
  bool is_controlling_instance() const { return is_controlling_instance_; }

  void PushPropertiesTo(Animation* other) const;

  void set_is_impl_only(bool is_impl_only) { is_impl_only_ = is_impl_only; }
  bool is_impl_only() const { return is_impl_only_; }

  void set_affects_active_elements(bool affects_active_elements) {
    affects_active_elements_ = affects_active_elements;
  }
  bool affects_active_elements() const { return affects_active_elements_; }

  void set_affects_pending_elements(bool affects_pending_elements) {
    affects_pending_elements_ = affects_pending_elements;
  }
  bool affects_pending_elements() const { return affects_pending_elements_; }

 private:
  Animation(std::unique_ptr<AnimationCurve> curve,
            int animation_id,
            int group_id,
            TargetProperty::Type target_property);

  base::TimeDelta ConvertToActiveTime(base::TimeTicks monotonic_time) const;

  std::unique_ptr<AnimationCurve> curve_;

  // IDs must be unique.
  int id_;

  // Animations that must be run together are called 'grouped' and have the same
  // group id. Grouped animations are guaranteed to start at the same time and
  // no other animations may animate any of the group's target properties until
  // all animations in the group have finished animating.
  int group_;

  TargetProperty::Type target_property_;
  RunState run_state_;
  double iterations_;
  double iteration_start_;
  base::TimeTicks start_time_;
  Direction direction_;
  double playback_rate_;
  FillMode fill_mode_;

  // The time offset effectively pushes the start of the animation back in time.
  // This is used for resuming paused animations -- an animation is added with a
  // non-zero time offset, causing the animation to skip ahead to the desired
  // point in time.
  base::TimeDelta time_offset_;

  bool needs_synchronized_start_time_;
  bool received_finished_event_;

  // When an animation is suspended, it behaves as if it is paused and it also
  // ignores all run state changes until it is resumed. This is used for testing
  // purposes.
  bool suspended_;

  // These are used in TrimTimeToCurrentIteration to account for time
  // spent while paused. This is not included in AnimationState since it
  // there is absolutely no need for clients of this controller to know
  // about these values.
  base::TimeTicks pause_time_;
  base::TimeDelta total_paused_time_;

  // Animations lead dual lives. An active animation will be conceptually owned
  // by two controllers, one on the impl thread and one on the main. In reality,
  // there will be two separate Animation instances for the same animation. They
  // will have the same group id and the same target property (these two values
  // uniquely identify an animation). The instance on the impl thread is the
  // instance that ultimately controls the values of the animating layer and so
  // we will refer to it as the 'controlling instance'.
  bool is_controlling_instance_;

  bool is_impl_only_;

  // When pushed from a main-thread controller to a compositor-thread
  // controller, an animation will initially only affect pending elements
  // (corresponding to layers in the pending tree). Animations that only
  // affect pending elements are able to reach the STARTING state and tick
  // pending elements, but cannot proceed any further and do not tick active
  // elements. After activation, such animations affect both kinds of elements
  // and are able to proceed past the STARTING state. When the removal of
  // an animation is pushed from a main-thread controller to a
  // compositor-thread controller, this initially only makes the animation
  // stop affecting pending elements. After activation, such animations no
  // longer affect any elements, and are deleted.
  bool affects_active_elements_;
  bool affects_pending_elements_;

  DISALLOW_COPY_AND_ASSIGN(Animation);
};

}  // namespace cc

#endif  // CC_ANIMATION_ANIMATION_H_