ScrollController.mm [plain text]
/*
* Copyright (C) 2011-2017 Apple Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
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* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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*/
#import "config.h"
#import "ScrollController.h"
#import "LayoutSize.h"
#import "PlatformWheelEvent.h"
#import "WheelEventTestMonitor.h"
#import <sys/sysctl.h>
#import <sys/time.h>
#if ENABLE(CSS_SCROLL_SNAP)
#import "ScrollSnapAnimatorState.h"
#import "ScrollableArea.h"
#endif
#if PLATFORM(MAC)
#import <pal/spi/mac/NSScrollViewSPI.h>
#endif
#if ENABLE(RUBBER_BANDING) || ENABLE(CSS_SCROLL_SNAP)
namespace WebCore {
#if ENABLE(RUBBER_BANDING)
static const float scrollVelocityZeroingTimeout = 0.10f;
static const float rubberbandDirectionLockStretchRatio = 1;
static const float rubberbandMinimumRequiredDeltaBeforeStretch = 10;
#endif
#if PLATFORM(MAC)
static float elasticDeltaForTimeDelta(float initialPosition, float initialVelocity, float elapsedTime)
{
return _NSElasticDeltaForTimeDelta(initialPosition, initialVelocity, elapsedTime);
}
static float elasticDeltaForReboundDelta(float delta)
{
return _NSElasticDeltaForReboundDelta(delta);
}
static float reboundDeltaForElasticDelta(float delta)
{
return _NSReboundDeltaForElasticDelta(delta);
}
static float scrollWheelMultiplier()
{
static float multiplier = -1;
if (multiplier < 0) {
multiplier = [[NSUserDefaults standardUserDefaults] floatForKey:@"NSScrollWheelMultiplier"];
if (multiplier <= 0)
multiplier = 1;
}
return multiplier;
}
#endif
static ScrollEventAxis otherScrollEventAxis(ScrollEventAxis axis)
{
return axis == ScrollEventAxis::Horizontal ? ScrollEventAxis::Vertical : ScrollEventAxis::Horizontal;
}
ScrollController::ScrollController(ScrollControllerClient& client)
: m_client(client)
#if ENABLE(RUBBER_BANDING)
, m_snapRubberbandTimer(RunLoop::current(), this, &ScrollController::snapRubberBandTimerFired)
#endif
#if ENABLE(CSS_SCROLL_SNAP) && PLATFORM(MAC)
, m_statelessSnapTransitionTimer(RunLoop::current(), this, &ScrollController::statelessSnapTransitionTimerFired)
, m_scrollSnapTimer(RunLoop::current(), this, &ScrollController::scrollSnapTimerFired)
#endif
{
}
#if PLATFORM(MAC)
bool ScrollController::handleWheelEvent(const PlatformWheelEvent& wheelEvent)
{
#if ENABLE(CSS_SCROLL_SNAP)
if (!processWheelEventForScrollSnap(wheelEvent))
return false;
#endif
if (wheelEvent.phase() == PlatformWheelEventPhaseBegan) {
// First, check if we should rubber-band at all.
if (m_client.pinnedInDirection(FloatSize(-wheelEvent.deltaX(), 0))
&& !shouldRubberBandInHorizontalDirection(wheelEvent))
return false;
m_inScrollGesture = true;
m_momentumScrollInProgress = false;
m_ignoreMomentumScrolls = false;
m_lastMomentumScrollTimestamp = 0;
m_momentumVelocity = FloatSize();
IntSize stretchAmount = m_client.stretchAmount();
m_stretchScrollForce.setWidth(reboundDeltaForElasticDelta(stretchAmount.width()));
m_stretchScrollForce.setHeight(reboundDeltaForElasticDelta(stretchAmount.height()));
m_overflowScrollDelta = FloatSize();
stopSnapRubberbandTimer();
return true;
}
if (wheelEvent.phase() == PlatformWheelEventPhaseEnded) {
snapRubberBand();
return true;
}
bool isMomentumScrollEvent = (wheelEvent.momentumPhase() != PlatformWheelEventPhaseNone);
if (m_ignoreMomentumScrolls && (isMomentumScrollEvent || m_snapRubberbandTimerIsActive)) {
if (wheelEvent.momentumPhase() == PlatformWheelEventPhaseEnded) {
m_ignoreMomentumScrolls = false;
return true;
}
return false;
}
float deltaX = m_overflowScrollDelta.width();
float deltaY = m_overflowScrollDelta.height();
// Reset overflow values because we may decide to remove delta at various points and put it into overflow.
m_overflowScrollDelta = FloatSize();
IntSize stretchAmount = m_client.stretchAmount();
bool isVerticallyStretched = stretchAmount.height();
bool isHorizontallyStretched = stretchAmount.width();
float eventCoalescedDeltaX;
float eventCoalescedDeltaY;
if (isVerticallyStretched || isHorizontallyStretched) {
eventCoalescedDeltaX = -wheelEvent.unacceleratedScrollingDeltaX();
eventCoalescedDeltaY = -wheelEvent.unacceleratedScrollingDeltaY();
} else {
eventCoalescedDeltaX = -wheelEvent.deltaX();
eventCoalescedDeltaY = -wheelEvent.deltaY();
}
deltaX += eventCoalescedDeltaX;
deltaY += eventCoalescedDeltaY;
// Slightly prefer scrolling vertically by applying the = case to deltaY
if (fabsf(deltaY) >= fabsf(deltaX))
deltaX = 0;
else
deltaY = 0;
bool shouldStretch = false;
PlatformWheelEventPhase momentumPhase = wheelEvent.momentumPhase();
// If we are starting momentum scrolling then do some setup.
if (!m_momentumScrollInProgress && (momentumPhase == PlatformWheelEventPhaseBegan || momentumPhase == PlatformWheelEventPhaseChanged))
m_momentumScrollInProgress = true;
CFTimeInterval timeDelta = wheelEvent.timestamp().secondsSinceEpoch().value() - m_lastMomentumScrollTimestamp;
if (m_inScrollGesture || m_momentumScrollInProgress) {
if (m_lastMomentumScrollTimestamp && timeDelta > 0 && timeDelta < scrollVelocityZeroingTimeout) {
m_momentumVelocity.setWidth(eventCoalescedDeltaX / (float)timeDelta);
m_momentumVelocity.setHeight(eventCoalescedDeltaY / (float)timeDelta);
m_lastMomentumScrollTimestamp = wheelEvent.timestamp().secondsSinceEpoch().value();
} else {
m_lastMomentumScrollTimestamp = wheelEvent.timestamp().secondsSinceEpoch().value();
m_momentumVelocity = FloatSize();
}
if (isVerticallyStretched) {
if (!isHorizontallyStretched && m_client.pinnedInDirection(FloatSize(deltaX, 0))) {
// Stretching only in the vertical.
if (deltaY && (fabsf(deltaX / deltaY) < rubberbandDirectionLockStretchRatio))
deltaX = 0;
else if (fabsf(deltaX) < rubberbandMinimumRequiredDeltaBeforeStretch) {
m_overflowScrollDelta.setWidth(m_overflowScrollDelta.width() + deltaX);
deltaX = 0;
} else
m_overflowScrollDelta.setWidth(m_overflowScrollDelta.width() + deltaX);
}
} else if (isHorizontallyStretched) {
// Stretching only in the horizontal.
if (m_client.pinnedInDirection(FloatSize(0, deltaY))) {
if (deltaX && (fabsf(deltaY / deltaX) < rubberbandDirectionLockStretchRatio))
deltaY = 0;
else if (fabsf(deltaY) < rubberbandMinimumRequiredDeltaBeforeStretch) {
m_overflowScrollDelta.setHeight(m_overflowScrollDelta.height() + deltaY);
deltaY = 0;
} else
m_overflowScrollDelta.setHeight(m_overflowScrollDelta.height() + deltaY);
}
} else {
// Not stretching at all yet.
if (m_client.pinnedInDirection(FloatSize(deltaX, deltaY))) {
if (fabsf(deltaY) >= fabsf(deltaX)) {
if (fabsf(deltaX) < rubberbandMinimumRequiredDeltaBeforeStretch) {
m_overflowScrollDelta.setWidth(m_overflowScrollDelta.width() + deltaX);
deltaX = 0;
} else
m_overflowScrollDelta.setWidth(m_overflowScrollDelta.width() + deltaX);
}
shouldStretch = true;
}
}
}
if (deltaX || deltaY) {
if (!(shouldStretch || isVerticallyStretched || isHorizontallyStretched)) {
if (deltaY) {
deltaY *= scrollWheelMultiplier();
m_client.immediateScrollBy(FloatSize(0, deltaY));
}
if (deltaX) {
deltaX *= scrollWheelMultiplier();
m_client.immediateScrollBy(FloatSize(deltaX, 0));
}
} else {
if (!m_client.allowsHorizontalStretching(wheelEvent)) {
deltaX = 0;
eventCoalescedDeltaX = 0;
} else if (deltaX && !isHorizontallyStretched && !m_client.pinnedInDirection(FloatSize(deltaX, 0))) {
deltaX *= scrollWheelMultiplier();
m_client.immediateScrollByWithoutContentEdgeConstraints(FloatSize(deltaX, 0));
deltaX = 0;
}
if (!m_client.allowsVerticalStretching(wheelEvent)) {
deltaY = 0;
eventCoalescedDeltaY = 0;
} else if (deltaY && !isVerticallyStretched && !m_client.pinnedInDirection(FloatSize(0, deltaY))) {
deltaY *= scrollWheelMultiplier();
m_client.immediateScrollByWithoutContentEdgeConstraints(FloatSize(0, deltaY));
deltaY = 0;
}
IntSize stretchAmount = m_client.stretchAmount();
if (m_momentumScrollInProgress) {
if ((m_client.pinnedInDirection(FloatSize(eventCoalescedDeltaX, eventCoalescedDeltaY)) || (fabsf(eventCoalescedDeltaX) + fabsf(eventCoalescedDeltaY) <= 0)) && m_lastMomentumScrollTimestamp) {
m_ignoreMomentumScrolls = true;
m_momentumScrollInProgress = false;
snapRubberBand();
}
}
m_stretchScrollForce.setWidth(m_stretchScrollForce.width() + deltaX);
m_stretchScrollForce.setHeight(m_stretchScrollForce.height() + deltaY);
FloatSize dampedDelta(ceilf(elasticDeltaForReboundDelta(m_stretchScrollForce.width())), ceilf(elasticDeltaForReboundDelta(m_stretchScrollForce.height())));
m_client.immediateScrollByWithoutContentEdgeConstraints(dampedDelta - stretchAmount);
}
}
if (m_momentumScrollInProgress && momentumPhase == PlatformWheelEventPhaseEnded) {
m_momentumScrollInProgress = false;
m_ignoreMomentumScrolls = false;
m_lastMomentumScrollTimestamp = 0;
}
return true;
}
#endif
#if ENABLE(RUBBER_BANDING)
static inline float roundTowardZero(float num)
{
return num > 0 ? ceilf(num - 0.5f) : floorf(num + 0.5f);
}
static inline float roundToDevicePixelTowardZero(float num)
{
float roundedNum = roundf(num);
if (fabs(num - roundedNum) < 0.125)
num = roundedNum;
return roundTowardZero(num);
}
void ScrollController::snapRubberBandTimerFired()
{
if (isScrollSnapInProgress())
return;
if (!m_momentumScrollInProgress || m_ignoreMomentumScrolls) {
CFTimeInterval timeDelta = [NSDate timeIntervalSinceReferenceDate] - m_startTime;
if (m_startStretch == FloatSize()) {
m_startStretch = m_client.stretchAmount();
if (m_startStretch == FloatSize()) {
stopSnapRubberbandTimer();
m_stretchScrollForce = FloatSize();
m_startTime = 0;
m_startStretch = FloatSize();
m_origVelocity = FloatSize();
return;
}
m_origVelocity = m_momentumVelocity;
// Just like normal scrolling, prefer vertical rubberbanding
if (fabsf(m_origVelocity.height()) >= fabsf(m_origVelocity.width()))
m_origVelocity.setWidth(0);
// Don't rubber-band horizontally if it's not possible to scroll horizontally
if (!m_client.canScrollHorizontally())
m_origVelocity.setWidth(0);
// Don't rubber-band vertically if it's not possible to scroll vertically
if (!m_client.canScrollVertically())
m_origVelocity.setHeight(0);
}
FloatPoint delta(roundToDevicePixelTowardZero(elasticDeltaForTimeDelta(m_startStretch.width(), -m_origVelocity.width(), (float)timeDelta)),
roundToDevicePixelTowardZero(elasticDeltaForTimeDelta(m_startStretch.height(), -m_origVelocity.height(), (float)timeDelta)));
if (fabs(delta.x()) >= 1 || fabs(delta.y()) >= 1) {
m_client.immediateScrollByWithoutContentEdgeConstraints(FloatSize(delta.x(), delta.y()) - m_client.stretchAmount());
FloatSize newStretch = m_client.stretchAmount();
m_stretchScrollForce.setWidth(reboundDeltaForElasticDelta(newStretch.width()));
m_stretchScrollForce.setHeight(reboundDeltaForElasticDelta(newStretch.height()));
} else {
m_client.adjustScrollPositionToBoundsIfNecessary();
stopSnapRubberbandTimer();
m_stretchScrollForce = FloatSize();
m_startTime = 0;
m_startStretch = FloatSize();
m_origVelocity = FloatSize();
}
} else {
m_startTime = [NSDate timeIntervalSinceReferenceDate];
m_startStretch = FloatSize();
if (!isRubberBandInProgress())
stopSnapRubberbandTimer();
}
}
#endif
bool ScrollController::isRubberBandInProgress() const
{
#if ENABLE(RUBBER_BANDING) && PLATFORM(MAC)
if (!m_inScrollGesture && !m_momentumScrollInProgress && !m_snapRubberbandTimerIsActive)
return false;
return !m_client.stretchAmount().isZero();
#else
return false;
#endif
}
bool ScrollController::isScrollSnapInProgress() const
{
#if ENABLE(CSS_SCROLL_SNAP) && PLATFORM(MAC)
if (m_inScrollGesture || m_momentumScrollInProgress || m_scrollSnapTimer.isActive())
return true;
#endif
return false;
}
#if ENABLE(RUBBER_BANDING)
void ScrollController::startSnapRubberbandTimer()
{
m_client.startSnapRubberbandTimer();
m_snapRubberbandTimer.startRepeating(1_s / 60.);
m_client.deferWheelEventTestCompletionForReason(reinterpret_cast<WheelEventTestMonitor::ScrollableAreaIdentifier>(this), WheelEventTestMonitor::RubberbandInProgress);
}
void ScrollController::stopSnapRubberbandTimer()
{
m_client.stopSnapRubberbandTimer();
m_snapRubberbandTimer.stop();
m_snapRubberbandTimerIsActive = false;
m_client.removeWheelEventTestCompletionDeferralForReason(reinterpret_cast<WheelEventTestMonitor::ScrollableAreaIdentifier>(this), WheelEventTestMonitor::RubberbandInProgress);
}
void ScrollController::snapRubberBand()
{
CFTimeInterval timeDelta = [NSProcessInfo processInfo].systemUptime - m_lastMomentumScrollTimestamp;
if (m_lastMomentumScrollTimestamp && timeDelta >= scrollVelocityZeroingTimeout)
m_momentumVelocity = FloatSize();
m_inScrollGesture = false;
if (m_snapRubberbandTimerIsActive)
return;
m_startTime = [NSDate timeIntervalSinceReferenceDate];
m_startStretch = FloatSize();
m_origVelocity = FloatSize();
startSnapRubberbandTimer();
m_snapRubberbandTimerIsActive = true;
}
bool ScrollController::shouldRubberBandInHorizontalDirection(const PlatformWheelEvent& wheelEvent)
{
if (wheelEvent.deltaX() > 0)
return m_client.shouldRubberBandInDirection(ScrollLeft);
if (wheelEvent.deltaX() < 0)
return m_client.shouldRubberBandInDirection(ScrollRight);
return true;
}
#endif
#if ENABLE(CSS_SCROLL_SNAP)
#if PLATFORM(MAC)
static inline WheelEventStatus toWheelEventStatus(PlatformWheelEventPhase phase, PlatformWheelEventPhase momentumPhase)
{
if (phase == PlatformWheelEventPhaseNone) {
switch (momentumPhase) {
case PlatformWheelEventPhaseBegan:
return WheelEventStatus::InertialScrollBegin;
case PlatformWheelEventPhaseChanged:
return WheelEventStatus::InertialScrolling;
case PlatformWheelEventPhaseEnded:
return WheelEventStatus::InertialScrollEnd;
case PlatformWheelEventPhaseNone:
return WheelEventStatus::StatelessScrollEvent;
default:
return WheelEventStatus::Unknown;
}
}
if (momentumPhase == PlatformWheelEventPhaseNone) {
switch (phase) {
case PlatformWheelEventPhaseBegan:
case PlatformWheelEventPhaseMayBegin:
return WheelEventStatus::UserScrollBegin;
case PlatformWheelEventPhaseChanged:
return WheelEventStatus::UserScrolling;
case PlatformWheelEventPhaseEnded:
case PlatformWheelEventPhaseCancelled:
return WheelEventStatus::UserScrollEnd;
default:
return WheelEventStatus::Unknown;
}
}
return WheelEventStatus::Unknown;
}
bool ScrollController::shouldOverrideInertialScrolling() const
{
if (!m_scrollSnapState)
return false;
ScrollSnapState scrollSnapState = m_scrollSnapState->currentState();
return scrollSnapState == ScrollSnapState::Gliding || scrollSnapState == ScrollSnapState::DestinationReached;
}
void ScrollController::scheduleStatelessScrollSnap()
{
stopScrollSnapTimer();
m_statelessSnapTransitionTimer.stop();
if (!m_scrollSnapState)
return;
static const Seconds statelessScrollSnapDelay = 750_ms;
m_statelessSnapTransitionTimer.startOneShot(statelessScrollSnapDelay);
startDeferringWheelEventTestCompletionDueToScrollSnapping();
}
void ScrollController::statelessSnapTransitionTimerFired()
{
if (!m_scrollSnapState)
return;
m_scrollSnapState->transitionToSnapAnimationState(m_client.scrollExtent(), m_client.viewportSize(), m_client.pageScaleFactor(), m_client.scrollOffset());
startScrollSnapTimer();
}
void ScrollController::startDeferringWheelEventTestCompletionDueToScrollSnapping()
{
m_client.deferWheelEventTestCompletionForReason(reinterpret_cast<WheelEventTestMonitor::ScrollableAreaIdentifier>(this), WheelEventTestMonitor::ScrollSnapInProgress);
}
void ScrollController::stopDeferringWheelEventTestCompletionDueToScrollSnapping()
{
m_client.removeWheelEventTestCompletionDeferralForReason(reinterpret_cast<WheelEventTestMonitor::ScrollableAreaIdentifier>(this), WheelEventTestMonitor::ScrollSnapInProgress);
}
bool ScrollController::processWheelEventForScrollSnap(const PlatformWheelEvent& wheelEvent)
{
if (!m_scrollSnapState)
return true;
if (m_scrollSnapState->snapOffsetsForAxis(ScrollEventAxis::Horizontal).isEmpty() && m_scrollSnapState->snapOffsetsForAxis(ScrollEventAxis::Vertical).isEmpty())
return true;
WheelEventStatus status = toWheelEventStatus(wheelEvent.phase(), wheelEvent.momentumPhase());
bool isInertialScrolling = false;
switch (status) {
case WheelEventStatus::UserScrollBegin:
case WheelEventStatus::UserScrolling:
stopScrollSnapTimer();
m_scrollSnapState->transitionToUserInteractionState();
m_dragEndedScrollingVelocity = -wheelEvent.scrollingVelocity();
break;
case WheelEventStatus::UserScrollEnd:
m_scrollSnapState->transitionToSnapAnimationState(m_client.scrollExtent(), m_client.viewportSize(), m_client.pageScaleFactor(), m_client.scrollOffset());
startScrollSnapTimer();
break;
case WheelEventStatus::InertialScrollBegin:
m_scrollSnapState->transitionToGlideAnimationState(m_client.scrollExtent(), m_client.viewportSize(), m_client.pageScaleFactor(), m_client.scrollOffset(), m_dragEndedScrollingVelocity, FloatSize(-wheelEvent.deltaX(), -wheelEvent.deltaY()));
m_dragEndedScrollingVelocity = { };
isInertialScrolling = true;
break;
case WheelEventStatus::InertialScrolling:
case WheelEventStatus::InertialScrollEnd:
isInertialScrolling = true;
break;
case WheelEventStatus::StatelessScrollEvent:
m_scrollSnapState->transitionToUserInteractionState();
scheduleStatelessScrollSnap();
break;
case WheelEventStatus::Unknown:
ASSERT_NOT_REACHED();
break;
}
return !(isInertialScrolling && shouldOverrideInertialScrolling());
}
void ScrollController::startScrollSnapTimer()
{
if (m_scrollSnapTimer.isActive())
return;
startDeferringWheelEventTestCompletionDueToScrollSnapping();
m_client.startScrollSnapTimer();
m_scrollSnapTimer.startRepeating(1_s / 60.);
}
void ScrollController::stopScrollSnapTimer()
{
if (!m_scrollSnapTimer.isActive())
return;
stopDeferringWheelEventTestCompletionDueToScrollSnapping();
m_client.stopScrollSnapTimer();
m_scrollSnapTimer.stop();
}
void ScrollController::scrollSnapTimerFired()
{
if (!m_scrollSnapState) {
ASSERT_NOT_REACHED();
return;
}
bool isAnimationComplete;
auto animationOffset = m_scrollSnapState->currentAnimatedScrollOffset(isAnimationComplete);
auto currentOffset = m_client.scrollOffset();
m_client.immediateScrollByWithoutContentEdgeConstraints(FloatSize(animationOffset.x() - currentOffset.x(), animationOffset.y() - currentOffset.y()));
if (isAnimationComplete) {
m_scrollSnapState->transitionToDestinationReachedState();
stopScrollSnapTimer();
}
}
#endif // PLATFORM(MAC)
void ScrollController::updateScrollSnapState(const ScrollableArea& scrollableArea)
{
if (auto* snapOffsets = scrollableArea.horizontalSnapOffsets()) {
if (auto* snapOffsetRanges = scrollableArea.horizontalSnapOffsetRanges())
updateScrollSnapPoints(ScrollEventAxis::Horizontal, *snapOffsets, *snapOffsetRanges);
else
updateScrollSnapPoints(ScrollEventAxis::Horizontal, *snapOffsets, { });
} else
updateScrollSnapPoints(ScrollEventAxis::Horizontal, { }, { });
if (auto* snapOffsets = scrollableArea.verticalSnapOffsets()) {
if (auto* snapOffsetRanges = scrollableArea.verticalSnapOffsetRanges())
updateScrollSnapPoints(ScrollEventAxis::Vertical, *snapOffsets, *snapOffsetRanges);
else
updateScrollSnapPoints(ScrollEventAxis::Vertical, *snapOffsets, { });
} else
updateScrollSnapPoints(ScrollEventAxis::Vertical, { }, { });
}
void ScrollController::updateScrollSnapPoints(ScrollEventAxis axis, const Vector<LayoutUnit>& snapPoints, const Vector<ScrollOffsetRange<LayoutUnit>>& snapRanges)
{
if (!m_scrollSnapState) {
if (snapPoints.isEmpty())
return;
m_scrollSnapState = makeUnique<ScrollSnapAnimatorState>();
}
if (snapPoints.isEmpty() && m_scrollSnapState->snapOffsetsForAxis(otherScrollEventAxis(axis)).isEmpty())
m_scrollSnapState = nullptr;
else
m_scrollSnapState->setSnapOffsetsAndPositionRangesForAxis(axis, snapPoints, snapRanges);
}
unsigned ScrollController::activeScrollSnapIndexForAxis(ScrollEventAxis axis) const
{
if (!m_scrollSnapState)
return 0;
return m_scrollSnapState->activeSnapIndexForAxis(axis);
}
void ScrollController::setActiveScrollSnapIndexForAxis(ScrollEventAxis axis, unsigned index)
{
if (!m_scrollSnapState)
return;
m_scrollSnapState->setActiveSnapIndexForAxis(axis, index);
}
void ScrollController::setNearestScrollSnapIndexForAxisAndOffset(ScrollEventAxis axis, int offset)
{
if (!m_scrollSnapState)
return;
float scaleFactor = m_client.pageScaleFactor();
ScrollSnapAnimatorState& snapState = *m_scrollSnapState;
auto snapOffsets = snapState.snapOffsetsForAxis(axis);
if (!snapOffsets.size())
return;
LayoutUnit clampedOffset = std::min(std::max(LayoutUnit(offset / scaleFactor), snapOffsets.first()), snapOffsets.last());
unsigned activeIndex = 0;
closestSnapOffset(snapState.snapOffsetsForAxis(axis), snapState.snapOffsetRangesForAxis(axis), clampedOffset, 0, activeIndex);
if (activeIndex == activeScrollSnapIndexForAxis(axis))
return;
m_activeScrollSnapIndexDidChange = true;
setActiveScrollSnapIndexForAxis(axis, activeIndex);
}
void ScrollController::setActiveScrollSnapIndicesForOffset(int x, int y)
{
if (!m_scrollSnapState)
return;
setNearestScrollSnapIndexForAxisAndOffset(ScrollEventAxis::Horizontal, x);
setNearestScrollSnapIndexForAxisAndOffset(ScrollEventAxis::Vertical, y);
}
#endif
} // namespace WebCore
#endif // ENABLE(RUBBER_BANDING)