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/*
* Copyright (C) 2014-2015 Apple Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 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)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
* THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "config.h"
#include "ScrollSnapAnimatorState.h"
#include "Logging.h"
#include "ScrollExtents.h"
#include "ScrollingEffectsController.h"
#include <wtf/MathExtras.h>
#include <wtf/text/TextStream.h>
namespace WebCore {
ScrollSnapAnimatorState::~ScrollSnapAnimatorState() = default;
bool ScrollSnapAnimatorState::transitionToSnapAnimationState(const ScrollExtents& scrollExtents, float pageScale, const FloatPoint& initialOffset)
{
return setupAnimationForState(ScrollSnapState::Snapping, scrollExtents, pageScale, initialOffset, { }, { });
}
bool ScrollSnapAnimatorState::transitionToGlideAnimationState(const ScrollExtents& scrollExtents, float pageScale, const FloatPoint& initialOffset, const FloatSize& initialVelocity, const FloatSize& initialDelta)
{
return setupAnimationForState(ScrollSnapState::Gliding, scrollExtents, pageScale, initialOffset, initialVelocity, initialDelta);
}
bool ScrollSnapAnimatorState::setupAnimationForState(ScrollSnapState state, const ScrollExtents& scrollExtents, float pageScale, const FloatPoint& initialOffset, const FloatSize& initialVelocity, const FloatSize& initialDelta)
{
ASSERT(state == ScrollSnapState::Snapping || state == ScrollSnapState::Gliding);
if (m_currentState == state)
return false;
bool animating = m_scrollController.startMomentumScrollWithInitialVelocity(initialOffset, initialVelocity, initialDelta, [&](const FloatPoint& targetOffset) {
float targetOffsetX, targetOffsetY;
std::tie(targetOffsetX, m_activeSnapIndexX) = targetOffsetForStartOffset(ScrollEventAxis::Horizontal, scrollExtents, initialOffset.x(), targetOffset, pageScale, initialDelta.width());
std::tie(targetOffsetY, m_activeSnapIndexY) = targetOffsetForStartOffset(ScrollEventAxis::Vertical, scrollExtents, initialOffset.y(), targetOffset, pageScale, initialDelta.height());
LOG_WITH_STREAM(ScrollAnimations, stream << "ScrollSnapAnimatorState::setupAnimationForState() - target offset " << targetOffset << " modified to " << FloatPoint(targetOffsetX, targetOffsetY));
return FloatPoint { targetOffsetX, targetOffsetY };
});
if (!animating)
return false;
m_currentState = state;
return animating;
}
std::optional<unsigned> ScrollSnapAnimatorState::closestSnapPointForOffset(ScrollEventAxis axis, ScrollOffset scrollOffset, const ScrollExtents& scrollExtents, float pageScale) const
{
LayoutPoint layoutScrollOffset(scrollOffset.x() / pageScale, scrollOffset.y() / pageScale);
auto snapOffsets = snapOffsetsForAxis(axis);
LayoutSize viewportSize(scrollExtents.viewportSize);
std::optional<unsigned> activeIndex;
if (snapOffsets.size())
activeIndex = snapOffsetInfo().closestSnapOffset(axis, viewportSize, layoutScrollOffset, 0).second;
return activeIndex;
}
float ScrollSnapAnimatorState::adjustedScrollDestination(ScrollEventAxis axis, FloatPoint destinationOffset, float velocity, std::optional<float> originalOffset, const ScrollExtents& scrollExtents, float pageScale) const
{
auto snapOffsets = snapOffsetsForAxis(axis);
if (!snapOffsets.size())
return valueForAxis(destinationOffset, axis);
std::optional<LayoutUnit> originalOffsetInLayoutUnits;
if (originalOffset)
originalOffsetInLayoutUnits = LayoutUnit(*originalOffset / pageScale);
LayoutSize viewportSize(scrollExtents.viewportSize);
LayoutPoint layoutDestinationOffset(destinationOffset.x() / pageScale, destinationOffset.y() / pageScale);
LayoutUnit offset = snapOffsetInfo().closestSnapOffset(axis, viewportSize, layoutDestinationOffset, velocity, originalOffsetInLayoutUnits).first;
return offset * pageScale;
}
bool ScrollSnapAnimatorState::resnapAfterLayout(ScrollOffset scrollOffset, const ScrollExtents& scrollExtents, float pageScale)
{
bool snapPointChanged = false;
// If we are already snapped in a particular axis, maintain that. Otherwise, snap to the nearest eligible snap point.
auto activeHorizontalIndex = activeSnapIndexForAxis(ScrollEventAxis::Horizontal);
if (!activeHorizontalIndex || *activeHorizontalIndex >= snapOffsetsForAxis(ScrollEventAxis::Horizontal).size())
snapPointChanged |= setNearestScrollSnapIndexForAxisAndOffset(ScrollEventAxis::Horizontal, scrollOffset, scrollExtents, pageScale);
auto activeVerticalIndex = activeSnapIndexForAxis(ScrollEventAxis::Vertical);
if (!activeVerticalIndex || *activeVerticalIndex >= snapOffsetsForAxis(ScrollEventAxis::Vertical).size())
snapPointChanged |= setNearestScrollSnapIndexForAxisAndOffset(ScrollEventAxis::Vertical, scrollOffset, scrollExtents, pageScale);
return snapPointChanged;
}
bool ScrollSnapAnimatorState::setNearestScrollSnapIndexForAxisAndOffset(ScrollEventAxis axis, ScrollOffset scrollOffset, const ScrollExtents& scrollExtents, float pageScale)
{
auto activeIndex = closestSnapPointForOffset(axis, scrollOffset, scrollExtents, pageScale);
if (activeIndex == activeSnapIndexForAxis(axis))
return false;
setActiveSnapIndexForAxis(axis, activeIndex);
return true;
}
bool ScrollSnapAnimatorState::setNearestScrollSnapIndexForOffset(ScrollOffset scrollOffset, const ScrollExtents& scrollExtents, float pageScale)
{
bool snapIndexChanged = false;
snapIndexChanged |= setNearestScrollSnapIndexForAxisAndOffset(ScrollEventAxis::Horizontal, scrollOffset, scrollExtents, pageScale);
snapIndexChanged |= setNearestScrollSnapIndexForAxisAndOffset(ScrollEventAxis::Vertical, scrollOffset, scrollExtents, pageScale);
return snapIndexChanged;
}
void ScrollSnapAnimatorState::transitionToUserInteractionState()
{
teardownAnimationForState(ScrollSnapState::UserInteraction);
}
void ScrollSnapAnimatorState::transitionToDestinationReachedState()
{
teardownAnimationForState(ScrollSnapState::DestinationReached);
}
void ScrollSnapAnimatorState::teardownAnimationForState(ScrollSnapState state)
{
ASSERT(state == ScrollSnapState::UserInteraction || state == ScrollSnapState::DestinationReached);
if (m_currentState == state)
return;
m_scrollController.stopAnimatedScroll();
m_currentState = state;
}
std::pair<float, std::optional<unsigned>> ScrollSnapAnimatorState::targetOffsetForStartOffset(ScrollEventAxis axis, const ScrollExtents& scrollExtents, float startOffset, FloatPoint predictedOffset, float pageScale, float initialDelta) const
{
auto minScrollOffset = (axis == ScrollEventAxis::Horizontal) ? scrollExtents.minimumScrollOffset().x() : scrollExtents.minimumScrollOffset().y();
auto maxScrollOffset = (axis == ScrollEventAxis::Horizontal) ? scrollExtents.maximumScrollOffset().x() : scrollExtents.maximumScrollOffset().y();
const auto& snapOffsets = m_snapOffsetsInfo.offsetsForAxis(axis);
if (snapOffsets.isEmpty())
return std::make_pair(clampTo<float>(axis == ScrollEventAxis::Horizontal ? predictedOffset.x() : predictedOffset.y(), minScrollOffset, maxScrollOffset), std::nullopt);
LayoutPoint predictedLayoutOffset(predictedOffset.x() / pageScale, predictedOffset.y() / pageScale);
auto [targetOffset, snapIndex] = m_snapOffsetsInfo.closestSnapOffset(axis, LayoutSize { scrollExtents.viewportSize }, predictedLayoutOffset, initialDelta, LayoutUnit(startOffset / pageScale));
return std::make_pair(pageScale * clampTo<float>(float { targetOffset }, minScrollOffset, maxScrollOffset), snapIndex);
}
TextStream& operator<<(TextStream& ts, const ScrollSnapAnimatorState& state)
{
ts << "ScrollSnapAnimatorState";
ts.dumpProperty("snap offsets x", state.snapOffsetsForAxis(ScrollEventAxis::Horizontal));
ts.dumpProperty("snap offsets y", state.snapOffsetsForAxis(ScrollEventAxis::Vertical));
ts.dumpProperty("active snap index x", state.activeSnapIndexForAxis(ScrollEventAxis::Horizontal));
ts.dumpProperty("active snap index y", state.activeSnapIndexForAxis(ScrollEventAxis::Vertical));
return ts;
}
} // namespace WebCore
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