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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 RenderScrollbarPart_h
     27 #define RenderScrollbarPart_h
     28 
     29 #include "core/rendering/RenderBlock.h"
     30 #include "platform/scroll/ScrollTypes.h"
     31 
     32 namespace WebCore {
     33 
     34 class RenderScrollbar;
     35 
     36 class RenderScrollbarPart FINAL : public RenderBlock {
     37 public:
     38     static RenderScrollbarPart* createAnonymous(Document*, RenderScrollbar* = 0, ScrollbarPart = NoPart);
     39 
     40     virtual ~RenderScrollbarPart();
     41 
     42     virtual const char* renderName() const OVERRIDE { return "RenderScrollbarPart"; }
     43 
     44     virtual LayerType layerTypeRequired() const OVERRIDE { return NoLayer; }
     45 
     46     virtual void layout() OVERRIDE;
     47 
     48     void paintIntoRect(GraphicsContext*, const LayoutPoint&, const LayoutRect&);
     49 
     50     // Scrollbar parts needs to be rendered at device pixel boundaries.
     51     virtual LayoutUnit marginTop() const OVERRIDE { ASSERT(isIntegerValue(m_marginBox.top())); return m_marginBox.top(); }
     52     virtual LayoutUnit marginBottom() const OVERRIDE { ASSERT(isIntegerValue(m_marginBox.bottom())); return m_marginBox.bottom(); }
     53     virtual LayoutUnit marginLeft() const OVERRIDE { ASSERT(isIntegerValue(m_marginBox.left())); return m_marginBox.left(); }
     54     virtual LayoutUnit marginRight() const OVERRIDE { ASSERT(isIntegerValue(m_marginBox.right())); return m_marginBox.right(); }
     55 
     56     virtual bool isRenderScrollbarPart() const OVERRIDE { return true; }
     57     RenderObject* rendererOwningScrollbar() const;
     58 
     59 protected:
     60     virtual void styleWillChange(StyleDifference, const RenderStyle& newStyle) OVERRIDE;
     61     virtual void styleDidChange(StyleDifference, const RenderStyle* oldStyle) OVERRIDE;
     62     virtual void imageChanged(WrappedImagePtr, const IntRect* = 0) OVERRIDE;
     63 
     64 private:
     65     RenderScrollbarPart(RenderScrollbar*, ScrollbarPart);
     66 
     67     virtual void computePreferredLogicalWidths() OVERRIDE;
     68 
     69     // Have all padding getters return 0. The important point here is to avoid resolving percents
     70     // against the containing block, since scroll bar corners don't always have one (so it would
     71     // crash). Scroll bar corners are not actually laid out, and they don't have child content, so
     72     // what we return here doesn't really matter.
     73     virtual LayoutUnit paddingTop() const OVERRIDE { return LayoutUnit(); }
     74     virtual LayoutUnit paddingBottom() const OVERRIDE { return LayoutUnit(); }
     75     virtual LayoutUnit paddingLeft() const OVERRIDE { return LayoutUnit(); }
     76     virtual LayoutUnit paddingRight() const OVERRIDE { return LayoutUnit(); }
     77     virtual LayoutUnit paddingBefore() const OVERRIDE { return LayoutUnit(); }
     78     virtual LayoutUnit paddingAfter() const OVERRIDE { return LayoutUnit(); }
     79     virtual LayoutUnit paddingStart() const OVERRIDE { return LayoutUnit(); }
     80     virtual LayoutUnit paddingEnd() const OVERRIDE { return LayoutUnit(); }
     81 
     82     void layoutHorizontalPart();
     83     void layoutVerticalPart();
     84 
     85     void computeScrollbarWidth();
     86     void computeScrollbarHeight();
     87 
     88     RenderScrollbar* m_scrollbar;
     89     ScrollbarPart m_part;
     90 };
     91 
     92 DEFINE_RENDER_OBJECT_TYPE_CASTS(RenderScrollbarPart, isRenderScrollbarPart());
     93 
     94 } // namespace WebCore
     95 
     96 #endif // RenderScrollbarPart_h
     97