gecko-dev/layout/generic/ScrollAnimationPhysics.h

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1.5 KiB
C++

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* 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_layout_ScrollAnimationPhysics_h_
#define mozilla_layout_ScrollAnimationPhysics_h_
#include "mozilla/TimeStamp.h"
#include "nsPoint.h"
namespace mozilla {
class ScrollAnimationPhysics
{
public:
virtual void Update(const TimeStamp& aTime,
const nsPoint& aDestination,
const nsSize& aCurrentVelocity) = 0;
// Get the velocity at a point in time in nscoords/sec.
virtual nsSize VelocityAt(const TimeStamp& aTime) = 0;
// Returns the expected scroll position at a given point in time, in app
// units, relative to the scroll frame.
virtual nsPoint PositionAt(const TimeStamp& aTime) = 0;
virtual bool IsFinished(const TimeStamp& aTime) = 0;
virtual ~ScrollAnimationPhysics() {}
};
// Helper for accelerated wheel deltas. This can be called from the main thread
// or the APZ Controller thread.
static inline double
ComputeAcceleratedWheelDelta(double aDelta, int32_t aCounter, int32_t aFactor)
{
if (!aDelta) {
return aDelta;
}
return (aDelta * aCounter * double(aFactor) / 10);
}
static const uint32_t kScrollSeriesTimeoutMs = 80; // in milliseconds
} // namespace mozilla
#endif // mozilla_layout_ScrollAnimationPhysics_h_