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32 #include "platform/scroll/ScrollAnimator.h"
34 #include "platform/geometry/FloatPoint.h"
35 #include "platform/scroll/ScrollableArea.h"
36 #include "wtf/PassOwnPtr.h"
43 ScrollAnimator::ScrollAnimator(ScrollableArea* scrollableArea)
44 : m_scrollableArea(scrollableArea)
50 ScrollAnimator::~ScrollAnimator()
54 bool ScrollAnimator::scroll(ScrollbarOrientation orientation, ScrollGranularity, float step, float delta)
56 float& currentPos = (orientation == HorizontalScrollbar) ? m_currentPosX : m_currentPosY;
57 float newPos = clampScrollPosition(orientation, currentPos + step * delta);
58 if (currentPos == newPos)
62 notifyPositionChanged();
67 void ScrollAnimator::scrollToOffsetWithoutAnimation(const FloatPoint& offset)
69 m_currentPosX = offset.x();
70 m_currentPosY = offset.y();
71 notifyPositionChanged();
74 bool ScrollAnimator::handleWheelEvent(const PlatformWheelEvent& e)
76 bool canScrollX = m_scrollableArea->userInputScrollable(HorizontalScrollbar);
77 bool canScrollY = m_scrollableArea->userInputScrollable(VerticalScrollbar);
79 // Accept the event if we are scrollable in that direction and can still
80 // scroll any further.
81 float deltaX = canScrollX ? e.deltaX() : 0;
82 float deltaY = canScrollY ? e.deltaY() : 0;
87 ScrollGranularity granularity = e.hasPreciseScrollingDeltas() ? ScrollByPrecisePixel : ScrollByPixel;
89 ScrollGranularity granularity = ScrollByPixel;
92 IntSize maxForwardScrollDelta = m_scrollableArea->maximumScrollPosition() - m_scrollableArea->scrollPosition();
93 IntSize maxBackwardScrollDelta = m_scrollableArea->scrollPosition() - m_scrollableArea->minimumScrollPosition();
94 if ((deltaX < 0 && maxForwardScrollDelta.width() > 0)
95 || (deltaX > 0 && maxBackwardScrollDelta.width() > 0)
96 || (deltaY < 0 && maxForwardScrollDelta.height() > 0)
97 || (deltaY > 0 && maxBackwardScrollDelta.height() > 0)) {
101 if (e.granularity() == ScrollByPageWheelEvent) {
102 bool negative = deltaY < 0;
103 deltaY = m_scrollableArea->pageStep(VerticalScrollbar);
108 scroll(VerticalScrollbar, granularity, m_scrollableArea->pixelStep(VerticalScrollbar), -deltaY);
112 if (e.granularity() == ScrollByPageWheelEvent) {
113 bool negative = deltaX < 0;
114 deltaX = m_scrollableArea->pageStep(HorizontalScrollbar);
119 scroll(HorizontalScrollbar, granularity, m_scrollableArea->pixelStep(HorizontalScrollbar), -deltaX);
125 void ScrollAnimator::setCurrentPosition(const FloatPoint& position)
127 m_currentPosX = position.x();
128 m_currentPosY = position.y();
131 FloatPoint ScrollAnimator::currentPosition() const
133 return FloatPoint(m_currentPosX, m_currentPosY);
136 void ScrollAnimator::notifyPositionChanged()
138 m_scrollableArea->setScrollOffsetFromAnimation(IntPoint(m_currentPosX, m_currentPosY));
141 float ScrollAnimator::clampScrollPosition(ScrollbarOrientation orientation, float pos)
143 float maxScrollPos = m_scrollableArea->maximumScrollPosition(orientation);
144 float minScrollPos = m_scrollableArea->minimumScrollPosition(orientation);
145 return std::max(std::min(pos, maxScrollPos), minScrollPos);
148 } // namespace WebCore