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
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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
ScrollAnimator(ScrollableArea * scrollableArea)43 ScrollAnimator::ScrollAnimator(ScrollableArea* scrollableArea)
44 : m_scrollableArea(scrollableArea)
45 , m_currentPosX(0)
46 , m_currentPosY(0)
47 {
48 }
49
~ScrollAnimator()50 ScrollAnimator::~ScrollAnimator()
51 {
52 }
53
scroll(ScrollbarOrientation orientation,ScrollGranularity,float step,float multiplier)54 bool ScrollAnimator::scroll(ScrollbarOrientation orientation, ScrollGranularity, float step, float multiplier)
55 {
56 float* currentPos = (orientation == HorizontalScrollbar) ? &m_currentPosX : &m_currentPosY;
57 float newPos = clampScrollPosition(orientation, *currentPos + step * multiplier);
58 float delta = *currentPos - newPos;
59 if (*currentPos == newPos)
60 return false;
61 *currentPos = newPos;
62
63 notifyPositionChanged(orientation == HorizontalScrollbar ? FloatSize(delta, 0) : FloatSize(0, delta));
64
65 return true;
66 }
67
scrollToOffsetWithoutAnimation(const FloatPoint & offset)68 void ScrollAnimator::scrollToOffsetWithoutAnimation(const FloatPoint& offset)
69 {
70 FloatSize delta = FloatSize(offset.x() - m_currentPosX, offset.y() - m_currentPosY);
71 m_currentPosX = offset.x();
72 m_currentPosY = offset.y();
73 notifyPositionChanged(delta);
74 }
75
handleWheelEvent(const PlatformWheelEvent & e)76 bool ScrollAnimator::handleWheelEvent(const PlatformWheelEvent& e)
77 {
78 bool canScrollX = m_scrollableArea->userInputScrollable(HorizontalScrollbar);
79 bool canScrollY = m_scrollableArea->userInputScrollable(VerticalScrollbar);
80
81 // Accept the event if we are scrollable in that direction and can still
82 // scroll any further.
83 float deltaX = canScrollX ? e.deltaX() : 0;
84 float deltaY = canScrollY ? e.deltaY() : 0;
85
86 bool handled = false;
87
88 #if !OS(MACOSX)
89 ScrollGranularity granularity = e.hasPreciseScrollingDeltas() ? ScrollByPrecisePixel : ScrollByPixel;
90 #else
91 ScrollGranularity granularity = ScrollByPixel;
92 #endif
93
94 IntSize maxForwardScrollDelta = m_scrollableArea->maximumScrollPosition() - m_scrollableArea->scrollPosition();
95 IntSize maxBackwardScrollDelta = m_scrollableArea->scrollPosition() - m_scrollableArea->minimumScrollPosition();
96 if ((deltaX < 0 && maxForwardScrollDelta.width() > 0)
97 || (deltaX > 0 && maxBackwardScrollDelta.width() > 0)
98 || (deltaY < 0 && maxForwardScrollDelta.height() > 0)
99 || (deltaY > 0 && maxBackwardScrollDelta.height() > 0)) {
100 handled = true;
101
102 if (deltaY) {
103 if (e.granularity() == ScrollByPageWheelEvent) {
104 bool negative = deltaY < 0;
105 deltaY = m_scrollableArea->pageStep(VerticalScrollbar);
106 if (negative)
107 deltaY = -deltaY;
108 }
109
110 scroll(VerticalScrollbar, granularity, m_scrollableArea->pixelStep(VerticalScrollbar), -deltaY);
111 }
112
113 if (deltaX) {
114 if (e.granularity() == ScrollByPageWheelEvent) {
115 bool negative = deltaX < 0;
116 deltaX = m_scrollableArea->pageStep(HorizontalScrollbar);
117 if (negative)
118 deltaX = -deltaX;
119 }
120
121 scroll(HorizontalScrollbar, granularity, m_scrollableArea->pixelStep(HorizontalScrollbar), -deltaX);
122 }
123 }
124 return handled;
125 }
126
setCurrentPosition(const FloatPoint & position)127 void ScrollAnimator::setCurrentPosition(const FloatPoint& position)
128 {
129 m_currentPosX = position.x();
130 m_currentPosY = position.y();
131 }
132
currentPosition() const133 FloatPoint ScrollAnimator::currentPosition() const
134 {
135 return FloatPoint(m_currentPosX, m_currentPosY);
136 }
137
notifyPositionChanged(const FloatSize &)138 void ScrollAnimator::notifyPositionChanged(const FloatSize&)
139 {
140 m_scrollableArea->setScrollOffsetFromAnimation(IntPoint(m_currentPosX, m_currentPosY));
141 }
142
clampScrollPosition(ScrollbarOrientation orientation,float pos)143 float ScrollAnimator::clampScrollPosition(ScrollbarOrientation orientation, float pos)
144 {
145 float maxScrollPos = m_scrollableArea->maximumScrollPosition(orientation);
146 float minScrollPos = m_scrollableArea->minimumScrollPosition(orientation);
147 return std::max(std::min(pos, maxScrollPos), minScrollPos);
148 }
149
150 } // namespace WebCore
151