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#ifndef ScrollAnimator_h
32#define ScrollAnimator_h
33
34#include "FloatSize.h"
35#include "PlatformWheelEvent.h"
36#include "ScrollTypes.h"
37#include <wtf/FastMalloc.h>
38#include <wtf/Forward.h>
39
40namespace WebCore {
41
42class FloatPoint;
43class PlatformTouchEvent;
44class ScrollableArea;
45class Scrollbar;
46
47class ScrollAnimator {
48    WTF_MAKE_FAST_ALLOCATED;
49public:
50    static PassOwnPtr<ScrollAnimator> create(ScrollableArea*);
51
52    virtual ~ScrollAnimator();
53
54    // Computes a scroll destination for the given parameters.  Returns false if
55    // already at the destination.  Otherwise, starts scrolling towards the
56    // destination and returns true.  Scrolling may be immediate or animated.
57    // The base class implementation always scrolls immediately, never animates.
58    virtual bool scroll(ScrollbarOrientation, ScrollGranularity, float step, float multiplier);
59
60    virtual void scrollToOffsetWithoutAnimation(const FloatPoint&);
61
62    ScrollableArea* scrollableArea() const { return m_scrollableArea; }
63
64    virtual bool handleWheelEvent(const PlatformWheelEvent&);
65
66#if ENABLE(TOUCH_EVENTS)
67    virtual bool handleTouchEvent(const PlatformTouchEvent&);
68#endif
69
70#if PLATFORM(COCOA)
71    virtual void handleWheelEventPhase(PlatformWheelEventPhase) { }
72#endif
73
74    void setCurrentPosition(const FloatPoint&);
75    FloatPoint currentPosition() const;
76
77    virtual void cancelAnimations() { }
78    virtual void serviceScrollAnimations() { }
79
80    virtual void contentAreaWillPaint() const { }
81    virtual void mouseEnteredContentArea() const { }
82    virtual void mouseExitedContentArea() const { }
83    virtual void mouseMovedInContentArea() const { }
84    virtual void mouseEnteredScrollbar(Scrollbar*) const { }
85    virtual void mouseExitedScrollbar(Scrollbar*) const { }
86    virtual void willStartLiveResize() { }
87    virtual void contentsResized() const { }
88    virtual void willEndLiveResize() { }
89    virtual void contentAreaDidShow() const { }
90    virtual void contentAreaDidHide() const { }
91
92    virtual void lockOverlayScrollbarStateToHidden(bool) { }
93    virtual bool scrollbarsCanBeActive() const { return true; }
94
95    virtual void didAddVerticalScrollbar(Scrollbar*) { }
96    virtual void willRemoveVerticalScrollbar(Scrollbar*) { }
97    virtual void didAddHorizontalScrollbar(Scrollbar*) { }
98    virtual void willRemoveHorizontalScrollbar(Scrollbar*) { }
99
100    virtual void verticalScrollbarLayerDidChange() { }
101    virtual void horizontalScrollbarLayerDidChange() { }
102
103    virtual bool shouldScrollbarParticipateInHitTesting(Scrollbar*) { return true; }
104
105    virtual void notifyContentAreaScrolled(const FloatSize& delta) { UNUSED_PARAM(delta); }
106
107    virtual bool isRubberBandInProgress() const { return false; }
108
109protected:
110    explicit ScrollAnimator(ScrollableArea*);
111
112    virtual void notifyPositionChanged(const FloatSize& delta);
113
114    ScrollableArea* m_scrollableArea;
115    float m_currentPosX; // We avoid using a FloatPoint in order to reduce
116    float m_currentPosY; // subclass code complexity.
117};
118
119} // namespace WebCore
120
121#endif // ScrollAnimator_h
122