ScrollController.mm [plain text]
/*
* Copyright (C) 2011-2017 Apple Inc. All rights reserved.
*
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*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
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* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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#import "config.h"
#import "ScrollController.h"
#import "LayoutSize.h"
#import "Logging.h"
#import "PlatformWheelEvent.h"
#import "WheelEventTestMonitor.h"
#import <sys/sysctl.h>
#import <sys/time.h>
#import <wtf/text/TextStream.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 Seconds scrollVelocityZeroingTimeout = 100_ms;
static const float rubberbandDirectionLockStretchRatio = 1;
static const float rubberbandMinimumRequiredDeltaBeforeStretch = 10;
#endif
#if PLATFORM(MAC)
static float elasticDeltaForTimeDelta(float initialPosition, float initialVelocity, Seconds elapsedTime)
{
return _NSElasticDeltaForTimeDelta(initialPosition, initialVelocity, elapsedTime.seconds());
}
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)
{
}
ScrollController::~ScrollController()
{
ASSERT(m_timersWereStopped);
}
void ScrollController::stopAllTimers()
{
#if ENABLE(RUBBER_BANDING)
if (m_snapRubberbandTimer)
m_snapRubberbandTimer->stop();
#endif
#if ENABLE(CSS_SCROLL_SNAP) && PLATFORM(MAC)
if (m_statelessSnapTransitionTimer)
m_statelessSnapTransitionTimer->stop();
if (m_scrollSnapTimer)
m_scrollSnapTimer->stop();
#endif
#if ASSERT_ENABLED
m_timersWereStopped = true;
#endif
}
#if PLATFORM(MAC)
bool ScrollController::handleWheelEvent(const PlatformWheelEvent& wheelEvent)
{
#if ENABLE(CSS_SCROLL_SNAP)
if (processWheelEventForScrollSnap(wheelEvent))
return false; // FIXME: Why don't we report that we handled it?
#endif
if (wheelEvent.phase() == PlatformWheelEventPhaseMayBegin || wheelEvent.phase() == PlatformWheelEventPhaseCancelled)
return false;
if (wheelEvent.phase() == PlatformWheelEventPhaseBegan) {
// FIXME: Trying to decide if a gesture is horizontal or vertical at the "began" phase is very error-prone.
auto direction = directionFromEvent(wheelEvent, ScrollEventAxis::Horizontal);
// FIXME: pinnedInDirection() needs cleanup.
if (direction && m_client.pinnedInDirection(FloatSize(-wheelEvent.deltaX(), 0)) && !shouldRubberBandInDirection(direction.value()))
return false;
direction = directionFromEvent(wheelEvent, ScrollEventAxis::Vertical);
if (direction && m_client.pinnedInDirection(FloatSize(0, -wheelEvent.deltaY())) && !shouldRubberBandInDirection(direction.value()))
return false;
m_momentumScrollInProgress = false;
m_ignoreMomentumScrolls = false;
m_lastMomentumScrollTimestamp = { };
m_momentumVelocity = { };
IntSize stretchAmount = m_client.stretchAmount();
m_stretchScrollForce.setWidth(reboundDeltaForElasticDelta(stretchAmount.width()));
m_stretchScrollForce.setHeight(reboundDeltaForElasticDelta(stretchAmount.height()));
m_overflowScrollDelta = FloatSize();
stopSnapRubberbandTimer();
updateRubberBandingState();
return true;
}
if (wheelEvent.phase() == PlatformWheelEventPhaseEnded) {
snapRubberBand();
updateRubberBandingState();
return true;
}
bool isMomentumScrollEvent = (wheelEvent.momentumPhase() != PlatformWheelEventPhaseNone);
if (m_ignoreMomentumScrolls && (isMomentumScrollEvent || m_snapRubberbandTimer)) {
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
// FIXME: Use wheelDeltaBiasingTowardsVertical().
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;
auto timeDelta = wheelEvent.timestamp() - m_lastMomentumScrollTimestamp;
if (m_inScrollGesture || m_momentumScrollInProgress) {
if (m_lastMomentumScrollTimestamp && timeDelta > 0_s && timeDelta < scrollVelocityZeroingTimeout) {
m_momentumVelocity.setWidth(eventCoalescedDeltaX / timeDelta.seconds());
m_momentumVelocity.setHeight(eventCoalescedDeltaY / timeDelta.seconds());
m_lastMomentumScrollTimestamp = wheelEvent.timestamp();
} else {
m_lastMomentumScrollTimestamp = wheelEvent.timestamp();
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;
}
}
}
bool handled = 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 (deltaX) {
if (!m_client.allowsHorizontalStretching(wheelEvent)) {
deltaX = 0;
eventCoalescedDeltaX = 0;
handled = false;
} else if (!isHorizontallyStretched && !m_client.pinnedInDirection(FloatSize(deltaX, 0))) {
deltaX *= scrollWheelMultiplier();
m_client.immediateScrollByWithoutContentEdgeConstraints(FloatSize(deltaX, 0));
deltaX = 0;
}
}
if (deltaY) {
if (!m_client.allowsVerticalStretching(wheelEvent)) {
deltaY = 0;
eventCoalescedDeltaY = 0;
handled = false;
} else if (!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 = { };
}
updateRubberBandingState();
return handled;
}
#endif // PLATFORM(MAC)
FloatSize ScrollController::wheelDeltaBiasingTowardsVertical(const PlatformWheelEvent& wheelEvent)
{
auto deltaX = wheelEvent.deltaX();
auto deltaY = wheelEvent.deltaY();
if (fabsf(deltaY) >= fabsf(deltaX))
deltaX = 0;
else
deltaY = 0;
return { deltaX, deltaY };
}
Optional<ScrollDirection> ScrollController::directionFromEvent(const PlatformWheelEvent& wheelEvent, Optional<ScrollEventAxis> axis, WheelAxisBias bias)
{
// FIXME: It's impossible to infer direction from a single event, since the start of a gesture is either zero or
// has small deltas on both axes.
auto wheelDelta = FloatSize { wheelEvent.deltaX(), wheelEvent.deltaY() };
if (bias == WheelAxisBias::Vertical)
wheelDelta = wheelDeltaBiasingTowardsVertical(wheelEvent);
if (axis) {
switch (axis.value()) {
case ScrollEventAxis::Vertical:
if (wheelDelta.height() < 0)
return ScrollDown;
if (wheelDelta.height() > 0)
return ScrollUp;
break;
case ScrollEventAxis::Horizontal:
if (wheelDelta.width() > 0)
return ScrollLeft;
if (wheelDelta.width() < 0)
return ScrollRight;
}
return WTF::nullopt;
}
// Check Y first because vertical scrolling dominates.
if (wheelDelta.height() < 0)
return ScrollDown;
if (wheelDelta.height() > 0)
return ScrollUp;
if (wheelDelta.width() > 0)
return ScrollLeft;
if (wheelDelta.width() < 0)
return ScrollRight;
return WTF::nullopt;
}
#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) {
auto timeDelta = MonotonicTime::now() - m_startTime;
if (m_startStretch.isZero()) {
m_startStretch = m_client.stretchAmount();
if (m_startStretch == FloatSize()) {
stopSnapRubberbandTimer();
m_stretchScrollForce = { };
m_startTime = { };
m_startStretch = { };
m_origVelocity = { };
updateRubberBandingState();
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(), timeDelta)),
roundToDevicePixelTowardZero(elasticDeltaForTimeDelta(m_startStretch.height(), -m_origVelocity.height(), 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 = { };
m_startTime = { };
m_startStretch = { };
m_origVelocity = { };
}
} else {
m_startTime = MonotonicTime::now();
m_startStretch = { };
if (!isRubberBandInProgressInternal())
stopSnapRubberbandTimer();
}
updateRubberBandingState();
}
#endif
void ScrollController::scrollPositionChanged()
{
#if ENABLE(RUBBER_BANDING)
updateRubberBandingState();
#endif
}
bool ScrollController::usesScrollSnap() const
{
#if ENABLE(CSS_SCROLL_SNAP)
return !!m_scrollSnapState;
#else
return false;
#endif
}
bool ScrollController::isUserScrollInProgress() const
{
#if PLATFORM(MAC)
return m_inScrollGesture;
#else
return false;
#endif
}
bool ScrollController::isRubberBandInProgress() const
{
#if ENABLE(RUBBER_BANDING) && PLATFORM(MAC)
return m_isRubberBanding;
#else
return false;
#endif
}
bool ScrollController::isScrollSnapInProgress() const
{
if (!usesScrollSnap())
return false;
#if ENABLE(CSS_SCROLL_SNAP) && PLATFORM(MAC)
if (m_inScrollGesture || m_momentumScrollInProgress || m_scrollSnapTimer)
return true;
#endif
return false;
}
#if ENABLE(RUBBER_BANDING)
void ScrollController::startSnapRubberbandTimer()
{
m_client.willStartRubberBandSnapAnimation();
// Make a new one each time to ensure it fires on the current RunLoop.
m_snapRubberbandTimer = m_client.createTimer([this] {
snapRubberBandTimerFired();
});
m_snapRubberbandTimer->startRepeating(1_s / 60.);
m_client.deferWheelEventTestCompletionForReason(reinterpret_cast<WheelEventTestMonitor::ScrollableAreaIdentifier>(this), WheelEventTestMonitor::RubberbandInProgress);
}
void ScrollController::stopSnapRubberbandTimer()
{
m_client.didStopRubberbandSnapAnimation();
if (m_snapRubberbandTimer) {
m_snapRubberbandTimer->stop();
m_snapRubberbandTimer = nullptr;
}
m_client.removeWheelEventTestCompletionDeferralForReason(reinterpret_cast<WheelEventTestMonitor::ScrollableAreaIdentifier>(this), WheelEventTestMonitor::RubberbandInProgress);
}
void ScrollController::snapRubberBand()
{
auto timeDelta = WallTime::now() - m_lastMomentumScrollTimestamp;
if (m_lastMomentumScrollTimestamp && timeDelta >= scrollVelocityZeroingTimeout)
m_momentumVelocity = { };
if (m_snapRubberbandTimer)
return;
m_startTime = MonotonicTime::now();
m_startStretch = { };
m_origVelocity = { };
startSnapRubberbandTimer();
}
bool ScrollController::shouldRubberBandInHorizontalDirection(const PlatformWheelEvent& wheelEvent) const
{
auto direction = directionFromEvent(wheelEvent, ScrollEventAxis::Horizontal);
if (direction)
return shouldRubberBandInDirection(direction.value());
return true;
}
bool ScrollController::shouldRubberBandInDirection(ScrollDirection direction) const
{
return m_client.shouldRubberBandInDirection(direction);
}
bool ScrollController::isRubberBandInProgressInternal() const
{
if (!m_inScrollGesture && !m_momentumScrollInProgress && !m_snapRubberbandTimer)
return false;
return !m_client.stretchAmount().isZero();
}
void ScrollController::updateRubberBandingState()
{
bool isRubberBanding = isRubberBandInProgressInternal();
if (isRubberBanding == m_isRubberBanding)
return;
m_isRubberBanding = isRubberBanding;
m_client.rubberBandingStateChanged(m_isRubberBanding);
}
#endif // ENABLE(RUBBER_BANDING)
#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::MomentumScrollBegin;
case PlatformWheelEventPhaseChanged:
return WheelEventStatus::MomentumScrolling;
case PlatformWheelEventPhaseEnded:
return WheelEventStatus::MomentumScrollEnd;
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;
}
#if !LOG_DISABLED
static TextStream& operator<<(TextStream& ts, WheelEventStatus status)
{
switch (status) {
case WheelEventStatus::UserScrollBegin: ts << "UserScrollBegin"; break;
case WheelEventStatus::UserScrolling: ts << "UserScrolling"; break;
case WheelEventStatus::UserScrollEnd: ts << "UserScrollEnd"; break;
case WheelEventStatus::MomentumScrollBegin: ts << "MomentumScrollBegin"; break;
case WheelEventStatus::MomentumScrolling: ts << "MomentumScrolling"; break;
case WheelEventStatus::MomentumScrollEnd: ts << "MomentumScrollEnd"; break;
case WheelEventStatus::StatelessScrollEvent: ts << "StatelessScrollEvent"; break;
case WheelEventStatus::Unknown: ts << "Unknown"; break;
}
return ts;
}
#endif
bool ScrollController::shouldOverrideMomentumScrolling() const
{
if (!usesScrollSnap())
return false;
ScrollSnapState scrollSnapState = m_scrollSnapState->currentState();
return scrollSnapState == ScrollSnapState::Gliding || scrollSnapState == ScrollSnapState::DestinationReached;
}
void ScrollController::scheduleStatelessScrollSnap()
{
stopScrollSnapTimer();
if (m_statelessSnapTransitionTimer) {
m_statelessSnapTransitionTimer->stop();
m_statelessSnapTransitionTimer = nullptr;
}
if (!usesScrollSnap())
return;
static const Seconds statelessScrollSnapDelay = 750_ms;
m_statelessSnapTransitionTimer = m_client.createTimer([this] {
statelessSnapTransitionTimerFired();
});
m_statelessSnapTransitionTimer->startOneShot(statelessScrollSnapDelay);
startDeferringWheelEventTestCompletionDueToScrollSnapping();
}
void ScrollController::statelessSnapTransitionTimerFired()
{
m_statelessSnapTransitionTimer = nullptr;
if (!usesScrollSnap())
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 (!usesScrollSnap())
return false;
if (m_scrollSnapState->snapOffsetsForAxis(ScrollEventAxis::Horizontal).isEmpty() && m_scrollSnapState->snapOffsetsForAxis(ScrollEventAxis::Vertical).isEmpty())
return false;
auto status = toWheelEventStatus(wheelEvent.phase(), wheelEvent.momentumPhase());
LOG_WITH_STREAM(ScrollSnap, stream << "ScrollController " << this << " processWheelEventForScrollSnap: status " << status);
bool isMomentumScrolling = 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::MomentumScrollBegin:
m_scrollSnapState->transitionToGlideAnimationState(m_client.scrollExtent(), m_client.viewportSize(), m_client.pageScaleFactor(), m_client.scrollOffset(), m_dragEndedScrollingVelocity, FloatSize(-wheelEvent.deltaX(), -wheelEvent.deltaY()));
m_dragEndedScrollingVelocity = { };
isMomentumScrolling = true;
break;
case WheelEventStatus::MomentumScrolling:
case WheelEventStatus::MomentumScrollEnd:
isMomentumScrolling = true;
break;
case WheelEventStatus::StatelessScrollEvent:
m_scrollSnapState->transitionToUserInteractionState();
scheduleStatelessScrollSnap();
break;
case WheelEventStatus::Unknown:
ASSERT_NOT_REACHED();
break;
}
return isMomentumScrolling && shouldOverrideMomentumScrolling();
}
void ScrollController::updateGestureInProgressState(const PlatformWheelEvent& wheelEvent)
{
if (wheelEvent.isGestureBegin() || wheelEvent.isTransitioningToMomentumScroll())
m_inScrollGesture = true;
else if (wheelEvent.isEndOfNonMomentumScroll() || wheelEvent.isGestureCancel() || wheelEvent.isEndOfMomentumScroll())
m_inScrollGesture = false;
updateRubberBandingState();
}
void ScrollController::startScrollSnapTimer()
{
if (m_scrollSnapTimer)
return;
LOG_WITH_STREAM(ScrollSnap, stream << "ScrollController " << this << " startScrollSnapTimer (main thread " << isMainThread() << ")");
startDeferringWheelEventTestCompletionDueToScrollSnapping();
m_client.willStartScrollSnapAnimation();
m_scrollSnapTimer = m_client.createTimer([this] {
scrollSnapTimerFired();
});
m_scrollSnapTimer->startRepeating(1_s / 60.);
}
void ScrollController::stopScrollSnapTimer()
{
if (!m_scrollSnapTimer)
return;
LOG_WITH_STREAM(ScrollSnap, stream << "ScrollController " << this << " stopScrollSnapTimer (main thread " << isMainThread() << ")");
stopDeferringWheelEventTestCompletionDueToScrollSnapping();
m_client.didStopScrollSnapAnimation();
m_scrollSnapTimer->stop();
m_scrollSnapTimer = nullptr;
}
void ScrollController::scrollSnapTimerFired()
{
if (!usesScrollSnap()) {
ASSERT_NOT_REACHED();
return;
}
bool isAnimationComplete;
auto animationOffset = m_scrollSnapState->currentAnimatedScrollOffset(isAnimationComplete);
auto currentOffset = m_client.scrollOffset();
LOG_WITH_STREAM(ScrollSnap, stream << "ScrollController " << this << " scrollSnapTimerFired - isAnimationComplete " << isAnimationComplete << " currentOffset " << currentOffset << " (main thread " << isMainThread() << ")");
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, { }, { });
LOG_WITH_STREAM(ScrollSnap, stream << "ScrollController " << this << " updateScrollSnapState for " << scrollableArea << " new state " << ValueOrNull(m_scrollSnapState.get()));
}
void ScrollController::updateScrollSnapPoints(ScrollEventAxis axis, const Vector<LayoutUnit>& snapPoints, const Vector<ScrollOffsetRange<LayoutUnit>>& snapRanges)
{
bool shouldComputeCurrentSnapIndices = false;
if (!m_scrollSnapState) {
if (snapPoints.isEmpty())
return;
m_scrollSnapState = makeUnique<ScrollSnapAnimatorState>();
shouldComputeCurrentSnapIndices = true;
}
if (snapPoints.isEmpty() && m_scrollSnapState->snapOffsetsForAxis(otherScrollEventAxis(axis)).isEmpty())
m_scrollSnapState = nullptr;
else {
m_scrollSnapState->setSnapOffsetsAndPositionRangesForAxis(axis, snapPoints, snapRanges);
if (shouldComputeCurrentSnapIndices) {
setActiveScrollSnapIndicesForOffset(roundedIntPoint(m_client.scrollOffset()));
LOG_WITH_STREAM(ScrollSnap, stream << "ScrollController::updateScrollSnapPoints - computed initial snap indices: x " << m_scrollSnapState->activeSnapIndexForAxis(ScrollEventAxis::Horizontal) << ", y " << m_scrollSnapState->activeSnapIndexForAxis(ScrollEventAxis::Vertical));
}
}
}
unsigned ScrollController::activeScrollSnapIndexForAxis(ScrollEventAxis axis) const
{
if (!usesScrollSnap())
return 0;
return m_scrollSnapState->activeSnapIndexForAxis(axis);
}
void ScrollController::setActiveScrollSnapIndexForAxis(ScrollEventAxis axis, unsigned index)
{
if (!usesScrollSnap())
return;
m_scrollSnapState->setActiveSnapIndexForAxis(axis, index);
}
void ScrollController::setNearestScrollSnapIndexForAxisAndOffset(ScrollEventAxis axis, int offset)
{
if (!usesScrollSnap())
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(ScrollOffset offset)
{
if (!usesScrollSnap())
return;
setNearestScrollSnapIndexForAxisAndOffset(ScrollEventAxis::Horizontal, offset.x());
setNearestScrollSnapIndexForAxisAndOffset(ScrollEventAxis::Vertical, offset.y());
}
#endif
} // namespace WebCore
#endif // ENABLE(RUBBER_BANDING)