1/*
2 * Copyright (C) 2008 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 ScrollbarTheme_h
27#define ScrollbarTheme_h
28
29#include "GraphicsContext.h"
30#include "IntRect.h"
31#include "ScrollTypes.h"
32
33namespace WebCore {
34
35class PlatformMouseEvent;
36class ScrollbarThemeClient;
37class ScrollView;
38
39#if USE(ACCELERATED_COMPOSITING) && ENABLE(RUBBER_BANDING)
40class GraphicsLayer;
41#endif
42
43class ScrollbarTheme {
44    WTF_MAKE_NONCOPYABLE(ScrollbarTheme); WTF_MAKE_FAST_ALLOCATED;
45public:
46    ScrollbarTheme() { }
47    virtual ~ScrollbarTheme() {};
48
49    virtual void updateEnabledState(ScrollbarThemeClient*) { };
50
51    virtual bool paint(ScrollbarThemeClient*, GraphicsContext*, const IntRect& /*damageRect*/) { return false; }
52    virtual ScrollbarPart hitTest(ScrollbarThemeClient*, const IntPoint&) { return NoPart; }
53
54    virtual int scrollbarThickness(ScrollbarControlSize = RegularScrollbar) { return 0; }
55
56    virtual ScrollbarButtonsPlacement buttonsPlacement() const { return ScrollbarButtonsSingle; }
57
58    virtual bool supportsControlTints() const { return false; }
59    virtual bool usesOverlayScrollbars() const { return false; }
60    virtual void updateScrollbarOverlayStyle(ScrollbarThemeClient*) { }
61
62    virtual void themeChanged() {}
63
64    virtual bool invalidateOnMouseEnterExit() { return false; }
65
66    void invalidateParts(ScrollbarThemeClient* scrollbar, ScrollbarControlPartMask mask)
67    {
68        if (mask & BackButtonStartPart)
69            invalidatePart(scrollbar, BackButtonStartPart);
70        if (mask & ForwardButtonStartPart)
71            invalidatePart(scrollbar, ForwardButtonStartPart);
72        if (mask & BackTrackPart)
73            invalidatePart(scrollbar, BackTrackPart);
74        if (mask & ThumbPart)
75            invalidatePart(scrollbar, ThumbPart);
76        if (mask & ForwardTrackPart)
77            invalidatePart(scrollbar, ForwardTrackPart);
78        if (mask & BackButtonEndPart)
79            invalidatePart(scrollbar, BackButtonEndPart);
80        if (mask & ForwardButtonEndPart)
81            invalidatePart(scrollbar, ForwardButtonEndPart);
82    }
83
84    virtual void invalidatePart(ScrollbarThemeClient*, ScrollbarPart) { }
85
86    virtual void paintScrollCorner(ScrollView*, GraphicsContext* context, const IntRect& cornerRect) { defaultPaintScrollCorner(context, cornerRect); }
87    static void defaultPaintScrollCorner(GraphicsContext* context, const IntRect& cornerRect) { context->fillRect(cornerRect, Color::white, ColorSpaceDeviceRGB); }
88
89    virtual void paintTickmarks(GraphicsContext*, ScrollbarThemeClient*, const IntRect&) { }
90    virtual void paintOverhangAreas(ScrollView*, GraphicsContext*, const IntRect&, const IntRect&, const IntRect&) { }
91
92#if USE(ACCELERATED_COMPOSITING) && ENABLE(RUBBER_BANDING)
93    virtual void setUpOverhangAreasLayerContents(GraphicsLayer*, const Color&) { }
94    virtual void setUpContentShadowLayer(GraphicsLayer*) { }
95#endif
96
97    virtual bool shouldCenterOnThumb(ScrollbarThemeClient*, const PlatformMouseEvent&) { return false; }
98    virtual bool shouldSnapBackToDragOrigin(ScrollbarThemeClient*, const PlatformMouseEvent&) { return false; }
99    virtual bool shouldDragDocumentInsteadOfThumb(ScrollbarThemeClient*, const PlatformMouseEvent&) { return false; }
100    virtual int thumbPosition(ScrollbarThemeClient*) { return 0; } // The position of the thumb relative to the track.
101    virtual int thumbLength(ScrollbarThemeClient*) { return 0; } // The length of the thumb along the axis of the scrollbar.
102    virtual int trackPosition(ScrollbarThemeClient*) { return 0; } // The position of the track relative to the scrollbar.
103    virtual int trackLength(ScrollbarThemeClient*) { return 0; } // The length of the track along the axis of the scrollbar.
104
105    virtual int maxOverlapBetweenPages() { return std::numeric_limits<int>::max(); }
106
107    virtual double initialAutoscrollTimerDelay() { return 0.25; }
108    virtual double autoscrollTimerDelay() { return 0.05; }
109
110    virtual void registerScrollbar(ScrollbarThemeClient*) { }
111    virtual void unregisterScrollbar(ScrollbarThemeClient*) { }
112
113    virtual bool isMockTheme() const { return false; }
114
115    static ScrollbarTheme* theme();
116
117private:
118    static ScrollbarTheme* nativeTheme(); // Must be implemented to return the correct theme subclass.
119};
120
121}
122#endif
123