Source/WebCore/rendering/RenderScrollbarPart.h

/*
 * Copyright (C) 2008 Apple Inc. All Rights Reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 
 */

#pragma once

#include "RenderBlock.h"
#include "ScrollTypes.h"

namespace WebCore {

class RenderScrollbar;

class RenderScrollbarPart final : public RenderBlock {
    WTF_MAKE_ISO_ALLOCATED(RenderScrollbarPart);
public:
    RenderScrollbarPart(Document&, RenderStyle&&, RenderScrollbar* = nullptr, ScrollbarPart = NoPart);
    
    virtual ~RenderScrollbarPart();

    const char* renderName() const override { return "RenderScrollbarPart"; }
    
    bool requiresLayer() const override { return false; }

    void layout() override;
    
    void paintIntoRect(GraphicsContext&, const LayoutPoint&, const LayoutRect&);

    // Scrollbar parts needs to be rendered at device pixel boundaries.
    LayoutUnit marginTop() const override { ASSERT(isIntegerValue(m_marginBox.top())); return m_marginBox.top(); }
    LayoutUnit marginBottom() const override { ASSERT(isIntegerValue(m_marginBox.bottom())); return m_marginBox.bottom(); }
    LayoutUnit marginLeft() const override { ASSERT(isIntegerValue(m_marginBox.left())); return m_marginBox.left(); }
    LayoutUnit marginRight() const override { ASSERT(isIntegerValue(m_marginBox.right())); return m_marginBox.right(); }

    RenderBox* rendererOwningScrollbar() const;

protected:
    void styleDidChange(StyleDifference, const RenderStyle* oldStyle) override;
    void imageChanged(WrappedImagePtr, const IntRect* = nullptr) override;

private:
    bool isRenderScrollbarPart() const override { return true; }
    void computePreferredLogicalWidths() override;

    void layoutHorizontalPart();
    void layoutVerticalPart();

    void computeScrollbarWidth();
    void computeScrollbarHeight();
    
    RenderScrollbar* m_scrollbar;
    ScrollbarPart m_part;
};

} // namespace WebCore

SPECIALIZE_TYPE_TRAITS_RENDER_OBJECT(RenderScrollbarPart, isRenderScrollbarPart())