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      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 "core/platform/ScrollTypes.h"
     30 #include "core/platform/graphics/GraphicsContext.h"
     31 #include "core/platform/graphics/IntRect.h"
     32 
     33 namespace WebCore {
     34 
     35 class PlatformMouseEvent;
     36 class ScrollbarThemeClient;
     37 class ScrollView;
     38 
     39 #if ENABLE(RUBBER_BANDING)
     40 class GraphicsLayer;
     41 #endif
     42 
     43 class ScrollbarTheme {
     44     WTF_MAKE_NONCOPYABLE(ScrollbarTheme); WTF_MAKE_FAST_ALLOCATED;
     45 public:
     46     ScrollbarTheme() { }
     47     virtual ~ScrollbarTheme() { }
     48 
     49     virtual void updateEnabledState(ScrollbarThemeClient*) { }
     50 
     51     virtual bool paint(ScrollbarThemeClient*, GraphicsContext*, const IntRect& damageRect);
     52     virtual ScrollbarPart hitTest(ScrollbarThemeClient*, const IntPoint&);
     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*, const IntRect& cornerRect);
     87 
     88     virtual void paintTickmarks(GraphicsContext*, ScrollbarThemeClient*, const IntRect&) { }
     89     virtual void paintOverhangAreas(ScrollView*, GraphicsContext*, const IntRect&, const IntRect&, const IntRect&);
     90 
     91     virtual bool shouldCenterOnThumb(ScrollbarThemeClient*, const PlatformMouseEvent&) { return false; }
     92     virtual bool shouldSnapBackToDragOrigin(ScrollbarThemeClient*, const PlatformMouseEvent&) { return false; }
     93     virtual bool shouldDragDocumentInsteadOfThumb(ScrollbarThemeClient*, const PlatformMouseEvent&) { return false; }
     94 
     95     // The position of the thumb relative to the track.
     96     virtual int thumbPosition(ScrollbarThemeClient*);
     97     // The length of the thumb along the axis of the scrollbar.
     98     virtual int thumbLength(ScrollbarThemeClient*);
     99     // The position of the track relative to the scrollbar.
    100     virtual int trackPosition(ScrollbarThemeClient*);
    101     // The length of the track along the axis of the scrollbar.
    102     virtual int trackLength(ScrollbarThemeClient*);
    103 
    104     virtual bool hasButtons(ScrollbarThemeClient*) = 0;
    105     virtual bool hasThumb(ScrollbarThemeClient*) = 0;
    106 
    107     virtual IntRect backButtonRect(ScrollbarThemeClient*, ScrollbarPart, bool painting = false) = 0;
    108     virtual IntRect forwardButtonRect(ScrollbarThemeClient*, ScrollbarPart, bool painting = false) = 0;
    109     virtual IntRect trackRect(ScrollbarThemeClient*, bool painting = false) = 0;
    110     virtual IntRect thumbRect(ScrollbarThemeClient*);
    111 
    112     virtual int minimumThumbLength(ScrollbarThemeClient*);
    113 
    114     virtual void splitTrack(ScrollbarThemeClient*, const IntRect& track, IntRect& startTrack, IntRect& thumb, IntRect& endTrack);
    115 
    116     virtual void paintScrollbarBackground(GraphicsContext*, ScrollbarThemeClient*) { }
    117     virtual void paintTrackBackground(GraphicsContext*, ScrollbarThemeClient*, const IntRect&) { }
    118     virtual void paintTrackPiece(GraphicsContext*, ScrollbarThemeClient*, const IntRect&, ScrollbarPart) { }
    119     virtual void paintButton(GraphicsContext*, ScrollbarThemeClient*, const IntRect&, ScrollbarPart) { }
    120     virtual void paintThumb(GraphicsContext*, ScrollbarThemeClient*, const IntRect&) { }
    121 
    122     virtual int maxOverlapBetweenPages() { return std::numeric_limits<int>::max(); }
    123 
    124     virtual double initialAutoscrollTimerDelay() { return 0.25; }
    125     virtual double autoscrollTimerDelay() { return 0.05; }
    126 
    127     virtual IntRect constrainTrackRectToTrackPieces(ScrollbarThemeClient*, const IntRect& rect) { return rect; }
    128 
    129     virtual void registerScrollbar(ScrollbarThemeClient*) { }
    130     virtual void unregisterScrollbar(ScrollbarThemeClient*) { }
    131 
    132     virtual bool isMockTheme() const { return false; }
    133 
    134     static ScrollbarTheme* theme();
    135 
    136 private:
    137     static ScrollbarTheme* nativeTheme(); // Must be implemented to return the correct theme subclass.
    138 };
    139 
    140 }
    141 #endif
    142