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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 "platform/PlatformExport.h"
     30 #include "platform/geometry/IntRect.h"
     31 #include "platform/scroll/ScrollTypes.h"
     32 
     33 namespace WebCore {
     34 
     35 class GraphicsContext;
     36 class PlatformMouseEvent;
     37 class ScrollbarThemeClient;
     38 class ScrollView;
     39 
     40 class PLATFORM_EXPORT ScrollbarTheme {
     41     WTF_MAKE_NONCOPYABLE(ScrollbarTheme); WTF_MAKE_FAST_ALLOCATED;
     42 public:
     43     ScrollbarTheme() { }
     44     virtual ~ScrollbarTheme() { }
     45 
     46     virtual void updateEnabledState(ScrollbarThemeClient*) { }
     47 
     48     virtual bool paint(ScrollbarThemeClient*, GraphicsContext*, const IntRect& damageRect);
     49     virtual ScrollbarPart hitTest(ScrollbarThemeClient*, const IntPoint&);
     50 
     51     virtual int scrollbarThickness(ScrollbarControlSize = RegularScrollbar) { return 0; }
     52 
     53     virtual ScrollbarButtonsPlacement buttonsPlacement() const { return ScrollbarButtonsSingle; }
     54 
     55     virtual bool supportsControlTints() const { return false; }
     56     virtual bool usesOverlayScrollbars() const { return false; }
     57     virtual void updateScrollbarOverlayStyle(ScrollbarThemeClient*) { }
     58 
     59     virtual bool invalidateOnMouseEnterExit() { return false; }
     60 
     61     void invalidateParts(ScrollbarThemeClient* scrollbar, ScrollbarControlPartMask mask)
     62     {
     63         if (mask & BackButtonStartPart)
     64             invalidatePart(scrollbar, BackButtonStartPart);
     65         if (mask & ForwardButtonStartPart)
     66             invalidatePart(scrollbar, ForwardButtonStartPart);
     67         if (mask & BackTrackPart)
     68             invalidatePart(scrollbar, BackTrackPart);
     69         if (mask & ThumbPart)
     70             invalidatePart(scrollbar, ThumbPart);
     71         if (mask & ForwardTrackPart)
     72             invalidatePart(scrollbar, ForwardTrackPart);
     73         if (mask & BackButtonEndPart)
     74             invalidatePart(scrollbar, BackButtonEndPart);
     75         if (mask & ForwardButtonEndPart)
     76             invalidatePart(scrollbar, ForwardButtonEndPart);
     77     }
     78 
     79     virtual void invalidatePart(ScrollbarThemeClient*, ScrollbarPart);
     80 
     81     virtual void paintScrollCorner(GraphicsContext*, const IntRect& cornerRect);
     82 
     83     virtual void paintTickmarks(GraphicsContext*, ScrollbarThemeClient*, const IntRect&) { }
     84     virtual void paintOverhangBackground(GraphicsContext*, const IntRect&, const IntRect&, const IntRect&);
     85     virtual void paintOverhangShadows(GraphicsContext*, const IntSize&, const IntRect&, const IntRect&, const IntRect&) { }
     86 
     87     virtual bool shouldCenterOnThumb(ScrollbarThemeClient*, const PlatformMouseEvent&);
     88     virtual bool shouldSnapBackToDragOrigin(ScrollbarThemeClient*, const PlatformMouseEvent&);
     89     virtual bool shouldDragDocumentInsteadOfThumb(ScrollbarThemeClient*, const PlatformMouseEvent&) { return false; }
     90 
     91     // The position of the thumb relative to the track.
     92     virtual int thumbPosition(ScrollbarThemeClient*);
     93     // The length of the thumb along the axis of the scrollbar.
     94     virtual int thumbLength(ScrollbarThemeClient*);
     95     // The position of the track relative to the scrollbar.
     96     virtual int trackPosition(ScrollbarThemeClient*);
     97     // The length of the track along the axis of the scrollbar.
     98     virtual int trackLength(ScrollbarThemeClient*);
     99 
    100     virtual bool hasButtons(ScrollbarThemeClient*) = 0;
    101     virtual bool hasThumb(ScrollbarThemeClient*) = 0;
    102 
    103     virtual IntRect backButtonRect(ScrollbarThemeClient*, ScrollbarPart, bool painting = false) = 0;
    104     virtual IntRect forwardButtonRect(ScrollbarThemeClient*, ScrollbarPart, bool painting = false) = 0;
    105     virtual IntRect trackRect(ScrollbarThemeClient*, bool painting = false) = 0;
    106     virtual IntRect thumbRect(ScrollbarThemeClient*);
    107     virtual int thumbThickness(ScrollbarThemeClient*);
    108 
    109     virtual int minimumThumbLength(ScrollbarThemeClient*);
    110 
    111     virtual void splitTrack(ScrollbarThemeClient*, const IntRect& track, IntRect& startTrack, IntRect& thumb, IntRect& endTrack);
    112 
    113     virtual void paintScrollbarBackground(GraphicsContext*, ScrollbarThemeClient*) { }
    114     virtual void paintTrackBackground(GraphicsContext*, ScrollbarThemeClient*, const IntRect&) { }
    115     virtual void paintTrackPiece(GraphicsContext*, ScrollbarThemeClient*, const IntRect&, ScrollbarPart) { }
    116     virtual void paintButton(GraphicsContext*, ScrollbarThemeClient*, const IntRect&, ScrollbarPart) { }
    117     virtual void paintThumb(GraphicsContext*, ScrollbarThemeClient*, const IntRect&) { }
    118 
    119     virtual int maxOverlapBetweenPages() { return std::numeric_limits<int>::max(); }
    120 
    121     virtual double initialAutoscrollTimerDelay() { return 0.25; }
    122     virtual double autoscrollTimerDelay() { return 0.05; }
    123 
    124     virtual IntRect constrainTrackRectToTrackPieces(ScrollbarThemeClient*, const IntRect& rect) { return rect; }
    125 
    126     virtual void registerScrollbar(ScrollbarThemeClient*) { }
    127     virtual void unregisterScrollbar(ScrollbarThemeClient*) { }
    128 
    129     virtual bool isMockTheme() const { return false; }
    130 
    131     static ScrollbarTheme* theme();
    132 
    133     static void setMockScrollbarsEnabled(bool flag);
    134     static bool mockScrollbarsEnabled();
    135 
    136 private:
    137     static ScrollbarTheme* nativeTheme(); // Must be implemented to return the correct theme subclass.
    138     static bool gMockScrollbarsEnabled;
    139 };
    140 
    141 }
    142 #endif
    143