forked from mirrors/gecko-dev
776d789d9a
These methods seem somewhat similar but they have two important differences: 1. Update() only changes the destination, not the current position. 2. ApplyContentShift() does not recompute the shape of the animation curve. Differential Revision: https://phabricator.services.mozilla.com/D141318
62 lines
2.4 KiB
C++
62 lines
2.4 KiB
C++
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* vim: set ts=8 sts=2 et sw=2 tw=80: */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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#ifndef mozilla_layout_ScrollAnimationPhysics_h_
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#define mozilla_layout_ScrollAnimationPhysics_h_
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#include "mozilla/TimeStamp.h"
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#include "nsPoint.h"
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#include "Units.h"
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namespace mozilla {
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class ScrollAnimationPhysics {
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public:
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// Update the animation to have |aDestination| as its new destination.
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// The animation's current position remains unchanged, and the shape
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// of the animation curve is recomputed between the current position
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// and the new destination.
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// This is used in cases where an input event that would cause another
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// animation of this kind is received while this animation is running.
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virtual void Update(const TimeStamp& aTime, const nsPoint& aDestination,
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const nsSize& aCurrentVelocity) = 0;
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// Shift both the current position and the destination of the animation
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// by |aShiftDelta|. The progress of the animation along its animation
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// curve is unchanged.
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// This is used in cases where the main thread changes the scroll offset
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// (e.g. via scrollBy()) but we want the "momentum" represented by the
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// animation to be preserved.
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virtual void ApplyContentShift(const CSSPoint& aShiftDelta) = 0;
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// Get the velocity at a point in time in nscoords/sec.
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virtual nsSize VelocityAt(const TimeStamp& aTime) = 0;
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// Returns the expected scroll position at a given point in time, in app
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// units, relative to the scroll frame.
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virtual nsPoint PositionAt(const TimeStamp& aTime) = 0;
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virtual bool IsFinished(const TimeStamp& aTime) = 0;
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virtual ~ScrollAnimationPhysics() = default;
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};
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// Helper for accelerated wheel deltas. This can be called from the main thread
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// or the APZ Controller thread.
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static inline double ComputeAcceleratedWheelDelta(double aDelta,
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int32_t aCounter,
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int32_t aFactor) {
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if (!aDelta) {
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return aDelta;
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}
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return (aDelta * aCounter * double(aFactor) / 10);
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}
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static const uint32_t kScrollSeriesTimeoutMs = 80; // in milliseconds
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} // namespace mozilla
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#endif // mozilla_layout_ScrollAnimationPhysics_h_
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