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
33namespace WebCore {
34
35class FloatPoint;
36class GraphicsContext;
37class PlatformGestureEvent;
38class PlatformWheelEvent;
39class ScrollAnimator;
40#if USE(ACCELERATED_COMPOSITING)
41class GraphicsLayer;
42#endif
43
44class ScrollableArea {
45public:
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.
61    bool constrainsScrollingToContentEdge() const { return m_constrainsScrollingToContentEdge; }
62    void setConstrainsScrollingToContentEdge(bool constrainsScrollingToContentEdge) { m_constrainsScrollingToContentEdge = constrainsScrollingToContentEdge; }
63
64    void setVerticalScrollElasticity(ScrollElasticity scrollElasticity) { m_verticalScrollElasticity = scrollElasticity; }
65    ScrollElasticity verticalScrollElasticity() const { return m_verticalScrollElasticity; }
66
67    void setHorizontalScrollElasticity(ScrollElasticity scrollElasticity) { m_horizontalScrollElasticity = scrollElasticity; }
68    ScrollElasticity horizontalScrollElasticity() const { return m_horizontalScrollElasticity; }
69
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
81    ScrollAnimator* scrollAnimator() const { return m_scrollAnimator.get(); }
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();
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.
100    virtual IntRect convertFromScrollbarToContainingView(const Scrollbar* scrollbar, const IntRect& scrollbarRect) const
101    {
102        return scrollbar->Widget::convertToContainingView(scrollbarRect);
103    }
104    virtual IntRect convertFromContainingViewToScrollbar(const Scrollbar* scrollbar, const IntRect& parentRect) const
105    {
106        return scrollbar->Widget::convertFromContainingView(parentRect);
107    }
108    virtual IntPoint convertFromScrollbarToContainingView(const Scrollbar* scrollbar, const IntPoint& scrollbarPoint) const
109    {
110        return scrollbar->Widget::convertToContainingView(scrollbarPoint);
111    }
112    virtual IntPoint convertFromContainingViewToScrollbar(const Scrollbar* scrollbar, const IntPoint& parentPoint) const
113    {
114        return scrollbar->Widget::convertFromContainingView(parentPoint);
115    }
116
117    virtual Scrollbar* horizontalScrollbar() const { return 0; }
118    virtual Scrollbar* verticalScrollbar() const { return 0; }
119
120    virtual IntPoint scrollPosition() const { ASSERT_NOT_REACHED(); return IntPoint(); }
121    virtual IntPoint minimumScrollPosition() const { ASSERT_NOT_REACHED(); return IntPoint(); }
122    virtual IntPoint maximumScrollPosition() const { ASSERT_NOT_REACHED(); return IntPoint(); }
123    virtual IntRect visibleContentRect(bool = false) const { ASSERT_NOT_REACHED(); return IntRect(); }
124    virtual int visibleHeight() const { ASSERT_NOT_REACHED(); return 0; }
125    virtual int visibleWidth() const { ASSERT_NOT_REACHED(); return 0; }
126    virtual IntSize contentsSize() const { ASSERT_NOT_REACHED(); return IntSize(); }
127    virtual IntSize overhangAmount() const { ASSERT_NOT_REACHED(); return IntSize(); }
128    virtual IntPoint currentMousePosition() const { return IntPoint(); }
129    virtual void didCompleteRubberBand(const IntSize&) const { ASSERT_NOT_REACHED(); }
130    virtual bool shouldSuspendScrollAnimations() const { return true; }
131    virtual void scrollbarStyleChanged() { }
132
133    virtual void disconnectFromPage() { }
134
135private:
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
148protected:
149    virtual void invalidateScrollbarRect(Scrollbar*, const IntRect&) = 0;
150    virtual void invalidateScrollCornerRect(const IntRect&) = 0;
151
152#if USE(ACCELERATED_COMPOSITING)
153    virtual GraphicsLayer* layerForHorizontalScrollbar() const { return 0; }
154    virtual GraphicsLayer* layerForVerticalScrollbar() const { return 0; }
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