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      1 /*
      2  * Copyright (C) 2004, 2006 Apple Computer, 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 COMPUTER, 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 COMPUTER, 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 Scrollbar_h
     27 #define Scrollbar_h
     28 
     29 #include "ScrollTypes.h"
     30 #include "Timer.h"
     31 #include "Widget.h"
     32 #include <wtf/MathExtras.h>
     33 #include <wtf/PassRefPtr.h>
     34 
     35 namespace WebCore {
     36 
     37 class GraphicsContext;
     38 class IntRect;
     39 class PlatformMouseEvent;
     40 class ScrollableArea;
     41 class ScrollbarTheme;
     42 
     43 class Scrollbar : public Widget {
     44 public:
     45     // Must be implemented by platforms that can't simply use the Scrollbar base class.  Right now the only platform that is not using the base class is GTK.
     46     static PassRefPtr<Scrollbar> createNativeScrollbar(ScrollableArea*, ScrollbarOrientation orientation, ScrollbarControlSize size);
     47 
     48     virtual ~Scrollbar();
     49 
     50     // Called by the ScrollableArea when the scroll offset changes.
     51     void offsetDidChange();
     52 
     53     static int pixelsPerLineStep() { return 40; }
     54     static float minFractionToStepWhenPaging() { return 0.875f; }
     55     static int maxOverlapBetweenPages();
     56 
     57     void disconnectFromScrollableArea() { m_scrollableArea = 0; }
     58     ScrollableArea* scrollableArea() const { return m_scrollableArea; }
     59 
     60     virtual bool isCustomScrollbar() const { return false; }
     61     ScrollbarOrientation orientation() const { return m_orientation; }
     62 
     63     int value() const { return lroundf(m_currentPos); }
     64     float currentPos() const { return m_currentPos; }
     65     int pressedPos() const { return m_pressedPos; }
     66     int visibleSize() const { return m_visibleSize; }
     67     int totalSize() const { return m_totalSize; }
     68     int maximum() const { return m_totalSize - m_visibleSize; }
     69     ScrollbarControlSize controlSize() const { return m_controlSize; }
     70 
     71     int lineStep() const { return m_lineStep; }
     72     int pageStep() const { return m_pageStep; }
     73     float pixelStep() const { return m_pixelStep; }
     74 
     75     ScrollbarPart pressedPart() const { return m_pressedPart; }
     76     ScrollbarPart hoveredPart() const { return m_hoveredPart; }
     77     virtual void setHoveredPart(ScrollbarPart);
     78     virtual void setPressedPart(ScrollbarPart);
     79 
     80     void setSteps(int lineStep, int pageStep, int pixelsPerStep = 1);
     81     void setProportion(int visibleSize, int totalSize);
     82     void setPressedPos(int p) { m_pressedPos = p; }
     83 
     84     virtual void paint(GraphicsContext*, const IntRect& damageRect);
     85 
     86     bool enabled() const { return m_enabled; }
     87     virtual void setEnabled(bool e);
     88 
     89     virtual bool isOverlayScrollbar() const;
     90 
     91     bool isWindowActive() const;
     92 
     93     // These methods are used for platform scrollbars to give :hover feedback.  They will not get called
     94     // when the mouse went down in a scrollbar, since it is assumed the scrollbar will start
     95     // grabbing all events in that case anyway.
     96     bool mouseMoved(const PlatformMouseEvent&);
     97     bool mouseExited();
     98 
     99     // Used by some platform scrollbars to know when they've been released from capture.
    100     bool mouseUp();
    101 
    102     bool mouseDown(const PlatformMouseEvent&);
    103 
    104 #if PLATFORM(QT)
    105     // For platforms that wish to handle context menu events.
    106     // FIXME: This is misplaced.  Normal hit testing should be used to populate a correct
    107     // context menu.  There's no reason why the scrollbar should have to do it.
    108     bool contextMenu(const PlatformMouseEvent& event);
    109 #endif
    110 
    111     ScrollbarTheme* theme() const { return m_theme; }
    112 
    113     virtual void setParent(ScrollView*);
    114     virtual void setFrameRect(const IntRect&);
    115 
    116     virtual void invalidateRect(const IntRect&);
    117 
    118     bool suppressInvalidation() const { return m_suppressInvalidation; }
    119     void setSuppressInvalidation(bool s) { m_suppressInvalidation = s; }
    120 
    121     virtual void styleChanged() { }
    122 
    123     virtual IntRect convertToContainingView(const IntRect&) const;
    124     virtual IntRect convertFromContainingView(const IntRect&) const;
    125 
    126     virtual IntPoint convertToContainingView(const IntPoint&) const;
    127     virtual IntPoint convertFromContainingView(const IntPoint&) const;
    128 
    129 protected:
    130     Scrollbar(ScrollableArea*, ScrollbarOrientation, ScrollbarControlSize, ScrollbarTheme* = 0);
    131 
    132     void updateThumb();
    133     virtual void updateThumbPosition();
    134     virtual void updateThumbProportion();
    135 
    136     void autoscrollTimerFired(Timer<Scrollbar>*);
    137     void startTimerIfNeeded(double delay);
    138     void stopTimerIfNeeded();
    139     void autoscrollPressedPart(double delay);
    140     ScrollDirection pressedPartScrollDirection();
    141     ScrollGranularity pressedPartScrollGranularity();
    142 
    143     void moveThumb(int pos);
    144 
    145     ScrollableArea* m_scrollableArea;
    146     ScrollbarOrientation m_orientation;
    147     ScrollbarControlSize m_controlSize;
    148     ScrollbarTheme* m_theme;
    149 
    150     int m_visibleSize;
    151     int m_totalSize;
    152     float m_currentPos;
    153     float m_dragOrigin;
    154     int m_lineStep;
    155     int m_pageStep;
    156     float m_pixelStep;
    157 
    158     ScrollbarPart m_hoveredPart;
    159     ScrollbarPart m_pressedPart;
    160     int m_pressedPos;
    161 
    162     bool m_enabled;
    163 
    164     Timer<Scrollbar> m_scrollTimer;
    165     bool m_overlapsResizer;
    166 
    167     bool m_suppressInvalidation;
    168 
    169 private:
    170     virtual bool isScrollbar() const { return true; }
    171     virtual AXObjectCache* axObjectCache() const;
    172 };
    173 
    174 } // namespace WebCore
    175 
    176 #endif // Scrollbar_h
    177