1 /* 2 * Copyright (c) 2010, Google Inc. All rights reserved. 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions are 6 * met: 7 * 8 * * Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * * Redistributions in binary form must reproduce the above 11 * copyright notice, this list of conditions and the following disclaimer 12 * in the documentation and/or other materials provided with the 13 * distribution. 14 * * Neither the name of Google Inc. nor the names of its 15 * contributors may be used to endorse or promote products derived from 16 * this software without specific prior written permission. 17 * 18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 19 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 20 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 21 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 22 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 23 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 24 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 26 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 28 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 29 */ 30 31 #include "config.h" 32 #include "platform/scroll/ScrollAnimator.h" 33 34 #include "platform/geometry/FloatPoint.h" 35 #include "platform/scroll/ScrollableArea.h" 36 #include "wtf/PassOwnPtr.h" 37 #include <algorithm> 38 39 using namespace std; 40 41 namespace WebCore { 42 43 ScrollAnimator::ScrollAnimator(ScrollableArea* scrollableArea) 44 : m_scrollableArea(scrollableArea) 45 , m_currentPosX(0) 46 , m_currentPosY(0) 47 { 48 } 49 50 ScrollAnimator::~ScrollAnimator() 51 { 52 } 53 54 bool ScrollAnimator::scroll(ScrollbarOrientation orientation, ScrollGranularity, float step, float delta) 55 { 56 float& currentPos = (orientation == HorizontalScrollbar) ? m_currentPosX : m_currentPosY; 57 float newPos = clampScrollPosition(orientation, currentPos + step * delta); 58 if (currentPos == newPos) 59 return false; 60 currentPos = newPos; 61 62 notifyPositionChanged(); 63 64 return true; 65 } 66 67 void ScrollAnimator::scrollToOffsetWithoutAnimation(const FloatPoint& offset) 68 { 69 m_currentPosX = offset.x(); 70 m_currentPosY = offset.y(); 71 notifyPositionChanged(); 72 } 73 74 bool ScrollAnimator::handleWheelEvent(const PlatformWheelEvent& e) 75 { 76 bool canScrollX = m_scrollableArea->userInputScrollable(HorizontalScrollbar); 77 bool canScrollY = m_scrollableArea->userInputScrollable(VerticalScrollbar); 78 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; 83 84 bool handled = false; 85 86 #if !OS(MACOSX) 87 ScrollGranularity granularity = e.hasPreciseScrollingDeltas() ? ScrollByPrecisePixel : ScrollByPixel; 88 #else 89 ScrollGranularity granularity = ScrollByPixel; 90 #endif 91 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)) { 98 handled = true; 99 100 if (deltaY) { 101 if (e.granularity() == ScrollByPageWheelEvent) { 102 bool negative = deltaY < 0; 103 deltaY = m_scrollableArea->pageStep(VerticalScrollbar); 104 if (negative) 105 deltaY = -deltaY; 106 } 107 108 scroll(VerticalScrollbar, granularity, m_scrollableArea->pixelStep(VerticalScrollbar), -deltaY); 109 } 110 111 if (deltaX) { 112 if (e.granularity() == ScrollByPageWheelEvent) { 113 bool negative = deltaX < 0; 114 deltaX = m_scrollableArea->pageStep(HorizontalScrollbar); 115 if (negative) 116 deltaX = -deltaX; 117 } 118 119 scroll(HorizontalScrollbar, granularity, m_scrollableArea->pixelStep(HorizontalScrollbar), -deltaX); 120 } 121 } 122 return handled; 123 } 124 125 void ScrollAnimator::setCurrentPosition(const FloatPoint& position) 126 { 127 m_currentPosX = position.x(); 128 m_currentPosY = position.y(); 129 } 130 131 FloatPoint ScrollAnimator::currentPosition() const 132 { 133 return FloatPoint(m_currentPosX, m_currentPosY); 134 } 135 136 void ScrollAnimator::notifyPositionChanged() 137 { 138 m_scrollableArea->setScrollOffsetFromAnimation(IntPoint(m_currentPosX, m_currentPosY)); 139 } 140 141 float ScrollAnimator::clampScrollPosition(ScrollbarOrientation orientation, float pos) 142 { 143 float maxScrollPos = m_scrollableArea->maximumScrollPosition(orientation); 144 float minScrollPos = m_scrollableArea->minimumScrollPosition(orientation); 145 return std::max(std::min(pos, maxScrollPos), minScrollPos); 146 } 147 148 } // namespace WebCore 149