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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 "GraphicsContext.h"
     30 #include "IntRect.h"
     31 #include "ScrollTypes.h"
     32 
     33 namespace WebCore {
     34 
     35 class PlatformMouseEvent;
     36 class Scrollbar;
     37 class ScrollView;
     38 
     39 class ScrollbarTheme {
     40     WTF_MAKE_NONCOPYABLE(ScrollbarTheme); WTF_MAKE_FAST_ALLOCATED;
     41 public:
     42     ScrollbarTheme() { }
     43     virtual ~ScrollbarTheme() {};
     44 
     45     virtual bool paint(Scrollbar*, GraphicsContext*, const IntRect& /*damageRect*/) { return false; }
     46     virtual ScrollbarPart hitTest(Scrollbar*, const PlatformMouseEvent&) { return NoPart; }
     47 
     48     virtual int scrollbarThickness(ScrollbarControlSize = RegularScrollbar) { return 0; }
     49 
     50     virtual ScrollbarButtonsPlacement buttonsPlacement() const { return ScrollbarButtonsSingle; }
     51 
     52     virtual bool supportsControlTints() const { return false; }
     53     virtual bool usesOverlayScrollbars() const { return false; }
     54 
     55     virtual void themeChanged() {}
     56 
     57     virtual bool invalidateOnMouseEnterExit() { return false; }
     58 
     59     void invalidateParts(Scrollbar* scrollbar, ScrollbarControlPartMask mask)
     60     {
     61         if (mask & BackButtonStartPart)
     62             invalidatePart(scrollbar, BackButtonStartPart);
     63         if (mask & ForwardButtonStartPart)
     64             invalidatePart(scrollbar, ForwardButtonStartPart);
     65         if (mask & BackTrackPart)
     66             invalidatePart(scrollbar, BackTrackPart);
     67         if (mask & ThumbPart)
     68             invalidatePart(scrollbar, ThumbPart);
     69         if (mask & ForwardTrackPart)
     70             invalidatePart(scrollbar, ForwardTrackPart);
     71         if (mask & BackButtonEndPart)
     72             invalidatePart(scrollbar, BackButtonEndPart);
     73         if (mask & ForwardButtonEndPart)
     74             invalidatePart(scrollbar, ForwardButtonEndPart);
     75     }
     76 
     77     virtual void invalidatePart(Scrollbar*, ScrollbarPart) {}
     78 
     79     virtual void paintScrollCorner(ScrollView*, GraphicsContext* context, const IntRect& cornerRect) { defaultPaintScrollCorner(context, cornerRect); }
     80     static void defaultPaintScrollCorner(GraphicsContext* context, const IntRect& cornerRect) { context->fillRect(cornerRect, Color::white, ColorSpaceDeviceRGB); }
     81 
     82     virtual bool shouldCenterOnThumb(Scrollbar*, const PlatformMouseEvent&) { return false; }
     83     virtual bool shouldSnapBackToDragOrigin(Scrollbar*, const PlatformMouseEvent&) { return false; }
     84     virtual int thumbPosition(Scrollbar*) { return 0; } // The position of the thumb relative to the track.
     85     virtual int thumbLength(Scrollbar*) { return 0; } // The length of the thumb along the axis of the scrollbar.
     86     virtual int trackPosition(Scrollbar*) { return 0; } // The position of the track relative to the scrollbar.
     87     virtual int trackLength(Scrollbar*) { return 0; } // The length of the track along the axis of the scrollbar.
     88 
     89     virtual int maxOverlapBetweenPages() { return std::numeric_limits<int>::max(); }
     90 
     91     virtual double initialAutoscrollTimerDelay() { return 0.25; }
     92     virtual double autoscrollTimerDelay() { return 0.05; }
     93 
     94     virtual void registerScrollbar(Scrollbar*) {}
     95     virtual void unregisterScrollbar(Scrollbar*) {}
     96 
     97     static ScrollbarTheme* nativeTheme(); // Must be implemented to return the correct theme subclass.
     98 };
     99 
    100 }
    101 #endif
    102