ScrollAnimator.cpp [plain text]
#include "config.h"
#include "ScrollAnimator.h"
#include "FloatPoint.h"
#include "PlatformWheelEvent.h"
#include "ScrollableArea.h"
#include <algorithm>
#include <wtf/PassOwnPtr.h>
using namespace std;
namespace WebCore {
ScrollAnimator::ScrollAnimator(ScrollableArea* scrollableArea)
: m_scrollableArea(scrollableArea)
, m_currentPosX(0)
, m_currentPosY(0)
{
}
ScrollAnimator::~ScrollAnimator()
{
}
bool ScrollAnimator::scroll(ScrollbarOrientation orientation, ScrollGranularity, float step, float multiplier)
{
float* currentPos = (orientation == HorizontalScrollbar) ? &m_currentPosX : &m_currentPosY;
float newPos = std::max(std::min(*currentPos + (step * multiplier), static_cast<float>(m_scrollableArea->scrollSize(orientation))), 0.0f);
if (*currentPos == newPos)
return false;
*currentPos = newPos;
notifyPositionChanged();
return true;
}
void ScrollAnimator::scrollToOffsetWithoutAnimation(const FloatPoint& offset)
{
m_currentPosX = offset.x();
m_currentPosY = offset.y();
notifyPositionChanged();
}
bool ScrollAnimator::handleWheelEvent(const PlatformWheelEvent& e)
{
Scrollbar* horizontalScrollbar = m_scrollableArea->horizontalScrollbar();
Scrollbar* verticalScrollbar = m_scrollableArea->verticalScrollbar();
float deltaX = horizontalScrollbar ? e.deltaX() : 0;
float deltaY = verticalScrollbar ? e.deltaY() : 0;
bool handled = false;
IntSize maxForwardScrollDelta = m_scrollableArea->maximumScrollPosition() - m_scrollableArea->scrollPosition();
IntSize maxBackwardScrollDelta = m_scrollableArea->scrollPosition() - m_scrollableArea->minimumScrollPosition();
if ((deltaX < 0 && maxForwardScrollDelta.width() > 0)
|| (deltaX > 0 && maxBackwardScrollDelta.width() > 0)
|| (deltaY < 0 && maxForwardScrollDelta.height() > 0)
|| (deltaY > 0 && maxBackwardScrollDelta.height() > 0)) {
handled = true;
if (e.granularity() == ScrollByPixelVelocityWheelEvent) {
scroll(VerticalScrollbar, ScrollByPixelVelocity, 0, -deltaY);
scroll(HorizontalScrollbar, ScrollByPixelVelocity, 0, -deltaX);
return handled;
}
if (deltaY) {
if (e.granularity() == ScrollByPageWheelEvent) {
bool negative = deltaY < 0;
deltaY = max(max(static_cast<float>(m_scrollableArea->visibleHeight()) * Scrollbar::minFractionToStepWhenPaging(), static_cast<float>(m_scrollableArea->visibleHeight() - Scrollbar::maxOverlapBetweenPages())), 1.0f);
if (negative)
deltaY = -deltaY;
}
scroll(VerticalScrollbar, ScrollByPixel, verticalScrollbar->pixelStep(), -deltaY);
}
if (deltaX) {
if (e.granularity() == ScrollByPageWheelEvent) {
bool negative = deltaX < 0;
deltaX = max(max(static_cast<float>(m_scrollableArea->visibleWidth()) * Scrollbar::minFractionToStepWhenPaging(), static_cast<float>(m_scrollableArea->visibleWidth() - Scrollbar::maxOverlapBetweenPages())), 1.0f);
if (negative)
deltaX = -deltaX;
}
scroll(HorizontalScrollbar, ScrollByPixel, horizontalScrollbar->pixelStep(), -deltaX);
}
}
return handled;
}
bool ScrollAnimator::handleTouchEvent(const PlatformTouchEvent&)
{
return false;
}
void ScrollAnimator::setCurrentPosition(const FloatPoint& position)
{
m_currentPosX = position.x();
m_currentPosY = position.y();
}
FloatPoint ScrollAnimator::currentPosition() const
{
return FloatPoint(m_currentPosX, m_currentPosY);
}
void ScrollAnimator::notifyPositionChanged()
{
m_scrollableArea->setScrollOffsetFromAnimation(IntPoint(m_currentPosX, m_currentPosY));
}
}