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AsyncPanZoomAnimation.h (3320B)

      1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
      2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
      3 /* This Source Code Form is subject to the terms of the Mozilla Public
      4 * License, v. 2.0. If a copy of the MPL was not distributed with this
      5 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
      6 
      7 #ifndef mozilla_layers_AsyncPanZoomAnimation_h_
      8 #define mozilla_layers_AsyncPanZoomAnimation_h_
      9 
     10 #include "APZUtils.h"
     11 #include "mozilla/RefPtr.h"
     12 #include "mozilla/TimeStamp.h"
     13 #include "nsISupportsImpl.h"
     14 #include "nsTArray.h"
     15 #include "nsThreadUtils.h"
     16 
     17 namespace mozilla {
     18 namespace layers {
     19 
     20 struct FrameMetrics;
     21 
     22 class WheelScrollAnimation;
     23 class OverscrollAnimation;
     24 class SmoothMsdScrollAnimation;
     25 class SmoothScrollAnimation;
     26 
     27 class AsyncPanZoomAnimation {
     28  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(AsyncPanZoomAnimation)
     29 
     30 public:
     31  explicit AsyncPanZoomAnimation() = default;
     32 
     33  virtual bool DoSample(FrameMetrics& aFrameMetrics,
     34                        const TimeDuration& aDelta) = 0;
     35 
     36  /**
     37   * Attempt to handle a main-thread scroll offset update without cancelling
     38   * the animation. This may or may not make sense depending on the type of
     39   * the animation and whether the scroll update is relative or absolute.
     40   *
     41   * If the scroll update is relative, |aRelativeDelta| will contain the
     42   * delta of the relative update. If the scroll update is absolute,
     43   * |aRelativeDelta| will be Nothing() (the animation can check the APZC's
     44   * FrameMetrics for the new absolute scroll offset if it wants to handle
     45   * and absolute update).
     46   *
     47   * Returns whether the animation could handle the scroll update. If the
     48   * return value is false, the animation will be cancelled.
     49   */
     50  virtual bool HandleScrollOffsetUpdate(const Maybe<CSSPoint>& aRelativeDelta) {
     51    return false;
     52  }
     53 
     54  bool Sample(FrameMetrics& aFrameMetrics, const TimeDuration& aDelta) {
     55    // In some situations, particularly when handoff is involved, it's possible
     56    // for |aDelta| to be negative on the first call to sample. Ignore such a
     57    // sample here, to avoid each derived class having to deal with this case.
     58    if (aDelta.ToMilliseconds() <= 0) {
     59      return true;
     60    }
     61 
     62    return DoSample(aFrameMetrics, aDelta);
     63  }
     64 
     65  /**
     66   * Get the deferred tasks in |mDeferredTasks| and place them in |aTasks|. See
     67   * |mDeferredTasks| for more information.  Clears |mDeferredTasks|.
     68   */
     69  nsTArray<RefPtr<Runnable>> TakeDeferredTasks() {
     70    return std::move(mDeferredTasks);
     71  }
     72 
     73  virtual SmoothScrollAnimation* AsSmoothScrollAnimation() { return nullptr; }
     74  virtual OverscrollAnimation* AsOverscrollAnimation() { return nullptr; }
     75 
     76  virtual bool WantsRepaints() { return true; }
     77 
     78  virtual void Cancel(CancelAnimationFlags aFlags) {}
     79 
     80  virtual bool WasTriggeredByScript() const { return false; }
     81 
     82 protected:
     83  // Protected destructor, to discourage deletion outside of Release():
     84  virtual ~AsyncPanZoomAnimation() = default;
     85 
     86  /**
     87   * Tasks scheduled for execution after the APZC's mMonitor is released.
     88   * Derived classes can add tasks here in Sample(), and the APZC can call
     89   * ExecuteDeferredTasks() to execute them.
     90   */
     91  nsTArray<RefPtr<Runnable>> mDeferredTasks;
     92 };
     93 
     94 }  // namespace layers
     95 }  // namespace mozilla
     96 
     97 #endif  // mozilla_layers_AsyncPanZoomAnimation_h_