AndroidVelocityTracker.h

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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */

/* vim: set ts=8 sts=2 et sw=2 tw=80: */

/* This Source Code Form is subject to the terms of the Mozilla Public

 * License, v. 2.0. If a copy of the MPL was not distributed with this

 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#ifndef mozilla_layers_AndroidVelocityTracker_h

#define mozilla_layers_AndroidVelocityTracker_h

#include <utility>

#include <cstdint>

#include "Axis.h"

#include "mozilla/Attributes.h"

#include "mozilla/Maybe.h"

#include "nsTArray.h"

namespace mozilla {

namespace layers {

class AndroidVelocityTracker : public VelocityTracker {

 public:

  explicit AndroidVelocityTracker();

  void StartTracking(ParentLayerCoord aPos, TimeStamp aTimestamp) override;

  Maybe<float> AddPosition(ParentLayerCoord aPos,

                           TimeStamp aTimestamp) override;

  Maybe<float> ComputeVelocity(TimeStamp aTimestamp) override;

  void Clear() override;

 private:

  // A queue of (timestamp, position) pairs; these are the historical

  // positions at the given timestamps.

  nsTArray<std::pair<TimeStamp, ParentLayerCoord>> mHistory;

  // The last time an event was added to the tracker, or the null moment if no

  // events have been added.

  TimeStamp mLastEventTime;

};

}  // namespace layers

}  // namespace mozilla

#endif