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1 /*
2  * Copyright (C) 2008, 2011 Apple 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
6  * are met:
7  * 1. Redistributions of source code must retain the above copyright
8  *    notice, this list of conditions and the following disclaimer.
9  * 2. Redistributions in binary form must reproduce the above copyright
10  *    notice, this list of conditions and the following disclaimer in the
11  *    documentation and/or other materials provided with the distribution.
12  *
13  * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
14  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
17  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
18  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
19  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
20  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
21  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
23  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24  */
25 
26 #ifndef ScrollableArea_h
27 #define ScrollableArea_h
28 
29 #include "IntRect.h"
30 #include "Scrollbar.h"
31 #include <wtf/Vector.h>
32 
33 namespace WebCore {
34 
35 class FloatPoint;
36 class GraphicsContext;
37 class PlatformGestureEvent;
38 class PlatformWheelEvent;
39 class ScrollAnimator;
40 #if USE(ACCELERATED_COMPOSITING)
41 class GraphicsLayer;
42 #endif
43 
44 class ScrollableArea {
45 public:
46     ScrollableArea();
47     virtual ~ScrollableArea();
48 
49     bool scroll(ScrollDirection, ScrollGranularity, float multiplier = 1);
50     void scrollToOffsetWithoutAnimation(const FloatPoint&);
51     void scrollToOffsetWithoutAnimation(ScrollbarOrientation, float offset);
52     void scrollToXOffsetWithoutAnimation(float x);
53     void scrollToYOffsetWithoutAnimation(float x);
54 
55     void handleWheelEvent(PlatformWheelEvent&);
56 #if ENABLE(GESTURE_EVENTS)
57     void handleGestureEvent(const PlatformGestureEvent&);
58 #endif
59 
60     // Functions for controlling if you can scroll past the end of the document.
constrainsScrollingToContentEdge()61     bool constrainsScrollingToContentEdge() const { return m_constrainsScrollingToContentEdge; }
setConstrainsScrollingToContentEdge(bool constrainsScrollingToContentEdge)62     void setConstrainsScrollingToContentEdge(bool constrainsScrollingToContentEdge) { m_constrainsScrollingToContentEdge = constrainsScrollingToContentEdge; }
63 
setVerticalScrollElasticity(ScrollElasticity scrollElasticity)64     void setVerticalScrollElasticity(ScrollElasticity scrollElasticity) { m_verticalScrollElasticity = scrollElasticity; }
verticalScrollElasticity()65     ScrollElasticity verticalScrollElasticity() const { return m_verticalScrollElasticity; }
66 
setHorizontalScrollElasticity(ScrollElasticity scrollElasticity)67     void setHorizontalScrollElasticity(ScrollElasticity scrollElasticity) { m_horizontalScrollElasticity = scrollElasticity; }
horizontalScrollElasticity()68     ScrollElasticity horizontalScrollElasticity() const { return m_horizontalScrollElasticity; }
69 
inLiveResize()70     bool inLiveResize() const { return m_inLiveResize; }
71     void willStartLiveResize();
72     void willEndLiveResize();
73 
74     void didAddVerticalScrollbar(Scrollbar*);
75     void willRemoveVerticalScrollbar(Scrollbar*);
76     void didAddHorizontalScrollbar(Scrollbar*);
77     void willRemoveHorizontalScrollbar(Scrollbar*);
78 
79     bool hasOverlayScrollbars() const;
80 
scrollAnimator()81     ScrollAnimator* scrollAnimator() const { return m_scrollAnimator.get(); }
scrollOrigin()82     const IntPoint& scrollOrigin() const { return m_scrollOrigin; }
83 
84     virtual bool isActive() const = 0;
85     virtual int scrollSize(ScrollbarOrientation) const = 0;
86     virtual int scrollPosition(Scrollbar*) const = 0;
87     void invalidateScrollbar(Scrollbar*, const IntRect&);
88     virtual bool isScrollCornerVisible() const = 0;
89     virtual IntRect scrollCornerRect() const = 0;
90     void invalidateScrollCorner();
getTickmarks(Vector<IntRect> &)91     virtual void getTickmarks(Vector<IntRect>&) const { }
92 
93     // This function should be overriden by subclasses to perform the actual
94     // scroll of the content.
95     virtual void setScrollOffset(const IntPoint&) = 0;
96 
97     // Convert points and rects between the scrollbar and its containing view.
98     // The client needs to implement these in order to be aware of layout effects
99     // like CSS transforms.
convertFromScrollbarToContainingView(const Scrollbar * scrollbar,const IntRect & scrollbarRect)100     virtual IntRect convertFromScrollbarToContainingView(const Scrollbar* scrollbar, const IntRect& scrollbarRect) const
101     {
102         return scrollbar->Widget::convertToContainingView(scrollbarRect);
103     }
convertFromContainingViewToScrollbar(const Scrollbar * scrollbar,const IntRect & parentRect)104     virtual IntRect convertFromContainingViewToScrollbar(const Scrollbar* scrollbar, const IntRect& parentRect) const
105     {
106         return scrollbar->Widget::convertFromContainingView(parentRect);
107     }
convertFromScrollbarToContainingView(const Scrollbar * scrollbar,const IntPoint & scrollbarPoint)108     virtual IntPoint convertFromScrollbarToContainingView(const Scrollbar* scrollbar, const IntPoint& scrollbarPoint) const
109     {
110         return scrollbar->Widget::convertToContainingView(scrollbarPoint);
111     }
convertFromContainingViewToScrollbar(const Scrollbar * scrollbar,const IntPoint & parentPoint)112     virtual IntPoint convertFromContainingViewToScrollbar(const Scrollbar* scrollbar, const IntPoint& parentPoint) const
113     {
114         return scrollbar->Widget::convertFromContainingView(parentPoint);
115     }
116 
horizontalScrollbar()117     virtual Scrollbar* horizontalScrollbar() const { return 0; }
verticalScrollbar()118     virtual Scrollbar* verticalScrollbar() const { return 0; }
119 
scrollPosition()120     virtual IntPoint scrollPosition() const { ASSERT_NOT_REACHED(); return IntPoint(); }
minimumScrollPosition()121     virtual IntPoint minimumScrollPosition() const { ASSERT_NOT_REACHED(); return IntPoint(); }
maximumScrollPosition()122     virtual IntPoint maximumScrollPosition() const { ASSERT_NOT_REACHED(); return IntPoint(); }
123     virtual IntRect visibleContentRect(bool = false) const { ASSERT_NOT_REACHED(); return IntRect(); }
visibleHeight()124     virtual int visibleHeight() const { ASSERT_NOT_REACHED(); return 0; }
visibleWidth()125     virtual int visibleWidth() const { ASSERT_NOT_REACHED(); return 0; }
contentsSize()126     virtual IntSize contentsSize() const { ASSERT_NOT_REACHED(); return IntSize(); }
overhangAmount()127     virtual IntSize overhangAmount() const { ASSERT_NOT_REACHED(); return IntSize(); }
currentMousePosition()128     virtual IntPoint currentMousePosition() const { return IntPoint(); }
didCompleteRubberBand(const IntSize &)129     virtual void didCompleteRubberBand(const IntSize&) const { ASSERT_NOT_REACHED(); }
shouldSuspendScrollAnimations()130     virtual bool shouldSuspendScrollAnimations() const { return true; }
scrollbarStyleChanged()131     virtual void scrollbarStyleChanged() { }
132 
disconnectFromPage()133     virtual void disconnectFromPage() { }
134 
135 private:
136     // NOTE: Only called from the ScrollAnimator.
137     friend class ScrollAnimator;
138     void setScrollOffsetFromAnimation(const IntPoint&);
139 
140     OwnPtr<ScrollAnimator> m_scrollAnimator;
141     bool m_constrainsScrollingToContentEdge;
142 
143     bool m_inLiveResize;
144 
145     ScrollElasticity m_verticalScrollElasticity;
146     ScrollElasticity m_horizontalScrollElasticity;
147 
148 protected:
149     virtual void invalidateScrollbarRect(Scrollbar*, const IntRect&) = 0;
150     virtual void invalidateScrollCornerRect(const IntRect&) = 0;
151 
152 #if USE(ACCELERATED_COMPOSITING)
layerForHorizontalScrollbar()153     virtual GraphicsLayer* layerForHorizontalScrollbar() const { return 0; }
layerForVerticalScrollbar()154     virtual GraphicsLayer* layerForVerticalScrollbar() const { return 0; }
layerForScrollCorner()155     virtual GraphicsLayer* layerForScrollCorner() const { return 0; }
156 #endif
157 
158     // There are 8 possible combinations of writing mode and direction. Scroll origin will be non-zero in the x or y axis
159     // if there is any reversed direction or writing-mode. The combinations are:
160     // writing-mode / direction     scrollOrigin.x() set    scrollOrigin.y() set
161     // horizontal-tb / ltr          NO                      NO
162     // horizontal-tb / rtl          YES                     NO
163     // horizontal-bt / ltr          NO                      YES
164     // horizontal-bt / rtl          YES                     YES
165     // vertical-lr / ltr            NO                      NO
166     // vertical-lr / rtl            NO                      YES
167     // vertical-rl / ltr            YES                     NO
168     // vertical-rl / rtl            YES                     YES
169     IntPoint m_scrollOrigin;
170 };
171 
172 } // namespace WebCore
173 
174 #endif // ScrollableArea_h
175