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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 19:33:14 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 19:33:14 +0000 |
commit | 36d22d82aa202bb199967e9512281e9a53db42c9 (patch) | |
tree | 105e8c98ddea1c1e4784a60a5a6410fa416be2de /layout/generic/ScrollAnimationBezierPhysics.cpp | |
parent | Initial commit. (diff) | |
download | firefox-esr-36d22d82aa202bb199967e9512281e9a53db42c9.tar.xz firefox-esr-36d22d82aa202bb199967e9512281e9a53db42c9.zip |
Adding upstream version 115.7.0esr.upstream/115.7.0esrupstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r-- | layout/generic/ScrollAnimationBezierPhysics.cpp | 152 |
1 files changed, 152 insertions, 0 deletions
diff --git a/layout/generic/ScrollAnimationBezierPhysics.cpp b/layout/generic/ScrollAnimationBezierPhysics.cpp new file mode 100644 index 0000000000..ffc69a9fa4 --- /dev/null +++ b/layout/generic/ScrollAnimationBezierPhysics.cpp @@ -0,0 +1,152 @@ +/* -*- 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/. */ + +#include "ScrollAnimationBezierPhysics.h" +#include "mozilla/StaticPrefs_general.h" + +using namespace mozilla; + +ScrollAnimationBezierPhysics::ScrollAnimationBezierPhysics( + const nsPoint& aStartPos, + const ScrollAnimationBezierPhysicsSettings& aSettings) + : mSettings(aSettings), mStartPos(aStartPos), mIsFirstIteration(true) {} + +void ScrollAnimationBezierPhysics::Update(const TimeStamp& aTime, + const nsPoint& aDestination, + const nsSize& aCurrentVelocity) { + if (mIsFirstIteration) { + InitializeHistory(aTime); + } + + TimeDuration duration = ComputeDuration(aTime); + nsSize currentVelocity = aCurrentVelocity; + + if (!mIsFirstIteration) { + // If an additional event has not changed the destination, then do not let + // another minimum duration reset slow things down. If it would then + // instead continue with the existing timing function. + if (aDestination == mDestination && + aTime + duration > mStartTime + mDuration) { + return; + } + + currentVelocity = VelocityAt(aTime); + mStartPos = PositionAt(aTime); + } + + mStartTime = aTime; + mDuration = duration; + mDestination = aDestination; + InitTimingFunction(mTimingFunctionX, mStartPos.x, currentVelocity.width, + aDestination.x); + InitTimingFunction(mTimingFunctionY, mStartPos.y, currentVelocity.height, + aDestination.y); + mIsFirstIteration = false; +} + +void ScrollAnimationBezierPhysics::ApplyContentShift( + const CSSPoint& aShiftDelta) { + nsPoint shiftDelta = CSSPoint::ToAppUnits(aShiftDelta); + mStartPos += shiftDelta; + mDestination += shiftDelta; +} + +TimeDuration ScrollAnimationBezierPhysics::ComputeDuration( + const TimeStamp& aTime) { + // Average last 3 delta durations (rounding errors up to 2ms are negligible + // for us) + int32_t eventsDeltaMs = (aTime - mPrevEventTime[2]).ToMilliseconds() / 3; + mPrevEventTime[2] = mPrevEventTime[1]; + mPrevEventTime[1] = mPrevEventTime[0]; + mPrevEventTime[0] = aTime; + + // Modulate duration according to events rate (quicker events -> shorter + // durations). The desired effect is to use longer duration when scrolling + // slowly, such that it's easier to follow, but reduce the duration to make it + // feel more snappy when scrolling quickly. To reduce fluctuations of the + // duration, we average event intervals using the recent 4 timestamps (now + + // three prev -> 3 intervals). + int32_t durationMS = + clamped<int32_t>(eventsDeltaMs * mSettings.mIntervalRatio, + mSettings.mMinMS, mSettings.mMaxMS); + + return TimeDuration::FromMilliseconds(durationMS); +} + +void ScrollAnimationBezierPhysics::InitializeHistory(const TimeStamp& aTime) { + // Starting a new scroll (i.e. not when extending an existing scroll + // animation), create imaginary prev timestamps with maximum relevant + // intervals between them. + + // Longest relevant interval (which results in maximum duration) + TimeDuration maxDelta = TimeDuration::FromMilliseconds( + mSettings.mMaxMS / mSettings.mIntervalRatio); + mPrevEventTime[0] = aTime - maxDelta; + mPrevEventTime[1] = mPrevEventTime[0] - maxDelta; + mPrevEventTime[2] = mPrevEventTime[1] - maxDelta; +} + +void ScrollAnimationBezierPhysics::InitTimingFunction( + SMILKeySpline& aTimingFunction, nscoord aCurrentPos, + nscoord aCurrentVelocity, nscoord aDestination) { + if (aDestination == aCurrentPos || + StaticPrefs::general_smoothScroll_currentVelocityWeighting() == 0) { + aTimingFunction.Init( + 0, 0, 1 - StaticPrefs::general_smoothScroll_stopDecelerationWeighting(), + 1); + return; + } + + const TimeDuration oneSecond = TimeDuration::FromSeconds(1); + double slope = + aCurrentVelocity * (mDuration / oneSecond) / (aDestination - aCurrentPos); + double normalization = sqrt(1.0 + slope * slope); + double dt = 1.0 / normalization * + StaticPrefs::general_smoothScroll_currentVelocityWeighting(); + double dxy = slope / normalization * + StaticPrefs::general_smoothScroll_currentVelocityWeighting(); + aTimingFunction.Init( + dt, dxy, + 1 - StaticPrefs::general_smoothScroll_stopDecelerationWeighting(), 1); +} + +nsPoint ScrollAnimationBezierPhysics::PositionAt(const TimeStamp& aTime) { + if (IsFinished(aTime)) { + return mDestination; + } + + double progressX = mTimingFunctionX.GetSplineValue(ProgressAt(aTime)); + double progressY = mTimingFunctionY.GetSplineValue(ProgressAt(aTime)); + return nsPoint(NSToCoordRound((1 - progressX) * mStartPos.x + + progressX * mDestination.x), + NSToCoordRound((1 - progressY) * mStartPos.y + + progressY * mDestination.y)); +} + +nsSize ScrollAnimationBezierPhysics::VelocityAt(const TimeStamp& aTime) { + if (IsFinished(aTime)) { + return nsSize(0, 0); + } + + double timeProgress = ProgressAt(aTime); + return nsSize(VelocityComponent(timeProgress, mTimingFunctionX, mStartPos.x, + mDestination.x), + VelocityComponent(timeProgress, mTimingFunctionY, mStartPos.y, + mDestination.y)); +} + +nscoord ScrollAnimationBezierPhysics::VelocityComponent( + double aTimeProgress, const SMILKeySpline& aTimingFunction, nscoord aStart, + nscoord aDestination) const { + double dt, dxy; + aTimingFunction.GetSplineDerivativeValues(aTimeProgress, dt, dxy); + if (dt == 0) return dxy >= 0 ? nscoord_MAX : nscoord_MIN; + + const TimeDuration oneSecond = TimeDuration::FromSeconds(1); + double slope = dxy / dt; + return NSToCoordRound(slope * (aDestination - aStart) / + (mDuration / oneSecond)); +} |