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 "ScrollAnimator.h"
33
34 #include "FloatPoint.h"
35 #include "PlatformWheelEvent.h"
36 #include "ScrollableArea.h"
37 #include <algorithm>
38 #include <wtf/PassOwnPtr.h>
39
40 using namespace std;
41
42 namespace WebCore {
43
44 #if !ENABLE(SMOOTH_SCROLLING)
create(ScrollableArea * scrollableArea)45 PassOwnPtr<ScrollAnimator> ScrollAnimator::create(ScrollableArea* scrollableArea)
46 {
47 return adoptPtr(new ScrollAnimator(scrollableArea));
48 }
49 #endif
50
ScrollAnimator(ScrollableArea * scrollableArea)51 ScrollAnimator::ScrollAnimator(ScrollableArea* scrollableArea)
52 : m_scrollableArea(scrollableArea)
53 , m_currentPosX(0)
54 , m_currentPosY(0)
55 {
56 }
57
~ScrollAnimator()58 ScrollAnimator::~ScrollAnimator()
59 {
60 }
61
scroll(ScrollbarOrientation orientation,ScrollGranularity,float step,float multiplier)62 bool ScrollAnimator::scroll(ScrollbarOrientation orientation, ScrollGranularity, float step, float multiplier)
63 {
64 float* currentPos = (orientation == HorizontalScrollbar) ? &m_currentPosX : &m_currentPosY;
65 float newPos = std::max(std::min(*currentPos + (step * multiplier), static_cast<float>(m_scrollableArea->scrollSize(orientation))), 0.0f);
66 if (*currentPos == newPos)
67 return false;
68 *currentPos = newPos;
69
70 notityPositionChanged();
71
72 return true;
73 }
74
scrollToOffsetWithoutAnimation(const FloatPoint & offset)75 void ScrollAnimator::scrollToOffsetWithoutAnimation(const FloatPoint& offset)
76 {
77 if (m_currentPosX != offset.x() || m_currentPosY != offset.y()) {
78 m_currentPosX = offset.x();
79 m_currentPosY = offset.y();
80 notityPositionChanged();
81 }
82 }
83
handleWheelEvent(PlatformWheelEvent & e)84 void ScrollAnimator::handleWheelEvent(PlatformWheelEvent& e)
85 {
86 Scrollbar* horizontalScrollbar = m_scrollableArea->horizontalScrollbar();
87 Scrollbar* verticalScrollbar = m_scrollableArea->verticalScrollbar();
88
89 // Accept the event if we have a scrollbar in that direction and can still
90 // scroll any further.
91 float deltaX = horizontalScrollbar ? e.deltaX() : 0;
92 float deltaY = verticalScrollbar ? e.deltaY() : 0;
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 e.accept();
101 if (e.granularity() == ScrollByPageWheelEvent) {
102 ASSERT(!e.deltaX());
103 bool negative = deltaY < 0;
104 deltaY = max(max(static_cast<float>(m_scrollableArea->visibleHeight()) * Scrollbar::minFractionToStepWhenPaging(), static_cast<float>(m_scrollableArea->visibleHeight() - Scrollbar::maxOverlapBetweenPages())), 1.0f);
105 if (negative)
106 deltaY = -deltaY;
107 }
108
109 if (deltaY)
110 scroll(VerticalScrollbar, ScrollByPixel, verticalScrollbar->pixelStep(), -deltaY);
111 if (deltaX)
112 scroll(HorizontalScrollbar, ScrollByPixel, horizontalScrollbar->pixelStep(), -deltaX);
113 }
114 }
115
116 #if ENABLE(GESTURE_EVENTS)
handleGestureEvent(const PlatformGestureEvent &)117 void ScrollAnimator::handleGestureEvent(const PlatformGestureEvent&)
118 {
119 }
120 #endif
121
currentPosition() const122 FloatPoint ScrollAnimator::currentPosition() const
123 {
124 return FloatPoint(m_currentPosX, m_currentPosY);
125 }
126
notityPositionChanged()127 void ScrollAnimator::notityPositionChanged()
128 {
129 m_scrollableArea->setScrollOffsetFromAnimation(IntPoint(m_currentPosX, m_currentPosY));
130 }
131
132 } // namespace WebCore
133