chromium/ui/compositor/callback_layer_animation_observer.h

// Copyright 2015 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef UI_COMPOSITOR_CALLBACK_LAYER_ANIMATION_OBSERVER_H_
#define UI_COMPOSITOR_CALLBACK_LAYER_ANIMATION_OBSERVER_H_

#include "base/functional/callback.h"
#include "ui/compositor/compositor_export.h"
#include "ui/compositor/layer_animation_observer.h"

namespace ui {

class LayerAnimationSequence;

// A LayerAnimationObserver that invokes a Callback when all observed
// LayerAnimationSequence's have started and finished.
//
// Example usage:
//  class Foobar {
//    // The Callback that will be invoked when all the animation sequences have
//    // started.
//    void AnimationStartedCallback(
//        const CallbackLayerAnimationObserver& observer) {
//      // Do stuff.
//    }
//
//    // The Callback that will be invoked when all the animation sequences have
//    // finished.
//    bool AnimationEndedCallback(
//        const CallbackLayerAnimationObserver& observer) {
//      // Do stuff.
//      return true;  // Returns true so that |observer| destroys itself.
//    }
//
//    // Example method that uses the CallbackLayerAnimationObserver.
//    void Animate() {
//      ui::LayerAnimator* animator_1 = layer_1->GetAnimator();
//      ui::LayerAnimator* animator_2 = layer_2->GetAnimator();
//      CallbackLayerAnimationObserver* observer =
//          new CallbackLayerAnimationObserver(
//              base::BindRepeating(&Foobar::AnimationStartedCallback),
//              base::Unretained(this));
//              base::BindRepeating(&Foobar::AnimationEndedCallback),
//              base::Unretained(this));
//      animator_1->AddObserver(observer);
//      animator_2->AddObserver(observer);
//
//      // Set up animation sequences on |animator_1| and |animator_2|.
//
//      // The callback won't be invoked until SetActive() is called.
//      observer->SetActive();
//    }
//  }
//
// TODO(bruthig): Unify the CallbackLayerAnimationObserver with the
// ImplicitAnimationObserver. (See www.crbug.com/542825).
class COMPOSITOR_EXPORT CallbackLayerAnimationObserver
    : public ui::LayerAnimationObserver { … };

}  // namespace ui

#endif  // UI_COMPOSITOR_CALLBACK_LAYER_ANIMATION_OBSERVER_H_