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 "ScrollTypes.h"
35 #include <wtf/Forward.h>
36 
37 namespace WebCore {
38 
39 class FloatPoint;
40 class PlatformWheelEvent;
41 class ScrollableArea;
42 class Scrollbar;
43 
44 #if ENABLE(GESTURE_EVENTS)
45 class PlatformGestureEvent;
46 #endif
47 
48 class ScrollAnimator {
49 public:
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 
scrollableArea()62     ScrollableArea* scrollableArea() const { return m_scrollableArea; }
63 
64     virtual void handleWheelEvent(PlatformWheelEvent&);
65 #if ENABLE(GESTURE_EVENTS)
66     virtual void handleGestureEvent(const PlatformGestureEvent&);
67 #endif
68 
69     FloatPoint currentPosition() const;
70 
cancelAnimations()71     virtual void cancelAnimations() { }
72 
contentAreaWillPaint()73     virtual void contentAreaWillPaint() const { }
mouseEnteredContentArea()74     virtual void mouseEnteredContentArea() const { }
mouseExitedContentArea()75     virtual void mouseExitedContentArea() const { }
mouseMovedInContentArea()76     virtual void mouseMovedInContentArea() const { }
willStartLiveResize()77     virtual void willStartLiveResize() { }
contentsResized()78     virtual void contentsResized() const { }
willEndLiveResize()79     virtual void willEndLiveResize() { }
contentAreaDidShow()80     virtual void contentAreaDidShow() const { }
contentAreaDidHide()81     virtual void contentAreaDidHide() const { }
82 
didAddVerticalScrollbar(Scrollbar *)83     virtual void didAddVerticalScrollbar(Scrollbar*) { }
willRemoveVerticalScrollbar(Scrollbar *)84     virtual void willRemoveVerticalScrollbar(Scrollbar*) { }
didAddHorizontalScrollbar(Scrollbar *)85     virtual void didAddHorizontalScrollbar(Scrollbar*) { }
willRemoveHorizontalScrollbar(Scrollbar *)86     virtual void willRemoveHorizontalScrollbar(Scrollbar*) { }
87 
88 protected:
89     ScrollAnimator(ScrollableArea*);
90 
91     virtual void notityPositionChanged();
92 
93     ScrollableArea* m_scrollableArea;
94     float m_currentPosX; // We avoid using a FloatPoint in order to reduce
95     float m_currentPosY; // subclass code complexity.
96 };
97 
98 } // namespace WebCore
99 
100 #endif // ScrollAnimator_h
101