Source/core/rendering/RenderLayerScrollableArea.h

/*
 * Copyright (C) 2003, 2009, 2012 Apple Inc. All rights reserved.
 *
 * Portions are Copyright (C) 1998 Netscape Communications Corporation.
 *
 * Other contributors:
 *   Robert O'Callahan <roc+@cs.cmu.edu>
 *   David Baron <dbaron@fas.harvard.edu>
 *   Christian Biesinger <cbiesinger@web.de>
 *   Randall Jesup <rjesup@wgate.com>
 *   Roland Mainz <roland.mainz@informatik.med.uni-giessen.de>
 *   Josh Soref <timeless@mac.com>
 *   Boris Zbarsky <bzbarsky@mit.edu>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 *
 * Alternatively, the contents of this file may be used under the terms
 * of either the Mozilla Public License Version 1.1, found at
 * http://www.mozilla.org/MPL/ (the "MPL") or the GNU General Public
 * License Version 2.0, found at http://www.fsf.org/copyleft/gpl.html
 * (the "GPL"), in which case the provisions of the MPL or the GPL are
 * applicable instead of those above.  If you wish to allow use of your
 * version of this file only under the terms of one of those two
 * licenses (the MPL or the GPL) and not to allow others to use your
 * version of this file under the LGPL, indicate your decision by
 * deletingthe provisions above and replace them with the notice and
 * other provisions required by the MPL or the GPL, as the case may be.
 * If you do not delete the provisions above, a recipient may use your
 * version of this file under any of the LGPL, the MPL or the GPL.
 */

#ifndef RenderLayerScrollableArea_h
#define RenderLayerScrollableArea_h

#include "core/platform/ScrollableArea.h"

namespace WebCore {

enum ResizerHitTestType {
    ResizerForPointer,
    ResizerForTouch
};

enum ScrollOffsetClamping {
    ScrollOffsetUnclamped,
    ScrollOffsetClamped
};

class RenderLayer;
class RenderLayerModelObject;

class RenderLayerScrollableArea FINAL : public ScrollableArea {
    // FIXME: Remove once the bits from RenderLayer have been moved here.
    friend class RenderLayer;
public:
    RenderLayerScrollableArea(RenderLayer*);
    virtual ~RenderLayerScrollableArea();

    virtual Scrollbar* horizontalScrollbar() const OVERRIDE;
    virtual Scrollbar* verticalScrollbar() const OVERRIDE;
    virtual ScrollableArea* enclosingScrollableArea() const OVERRIDE;

    virtual void updateNeedsCompositedScrolling() OVERRIDE;

    virtual GraphicsLayer* layerForScrolling() const OVERRIDE;
    virtual GraphicsLayer* layerForHorizontalScrollbar() const OVERRIDE;
    virtual GraphicsLayer* layerForVerticalScrollbar() const OVERRIDE;
    virtual GraphicsLayer* layerForScrollCorner() const OVERRIDE;
    virtual bool usesCompositedScrolling() const OVERRIDE;
    virtual void invalidateScrollbarRect(Scrollbar*, const IntRect&) OVERRIDE;
    virtual void invalidateScrollCornerRect(const IntRect&) OVERRIDE;
    virtual bool isActive() const OVERRIDE;
    virtual bool isScrollCornerVisible() const OVERRIDE;
    virtual IntRect scrollCornerRect() const OVERRIDE;
    virtual IntRect convertFromScrollbarToContainingView(const Scrollbar*, const IntRect&) const OVERRIDE;
    virtual IntRect convertFromContainingViewToScrollbar(const Scrollbar*, const IntRect&) const OVERRIDE;
    virtual IntPoint convertFromScrollbarToContainingView(const Scrollbar*, const IntPoint&) const OVERRIDE;
    virtual IntPoint convertFromContainingViewToScrollbar(const Scrollbar*, const IntPoint&) const OVERRIDE;
    virtual int scrollSize(ScrollbarOrientation) const OVERRIDE;
    virtual void setScrollOffset(const IntPoint&) OVERRIDE;
    virtual IntPoint scrollPosition() const OVERRIDE;
    virtual IntPoint minimumScrollPosition() const OVERRIDE;
    virtual IntPoint maximumScrollPosition() const OVERRIDE;
    virtual IntRect visibleContentRect(VisibleContentRectIncludesScrollbars) const OVERRIDE;
    virtual int visibleHeight() const OVERRIDE;
    virtual int visibleWidth() const OVERRIDE;
    virtual IntSize contentsSize() const OVERRIDE;
    virtual IntSize overhangAmount() const OVERRIDE;
    virtual IntPoint lastKnownMousePosition() const OVERRIDE;
    virtual bool shouldSuspendScrollAnimations() const OVERRIDE;
    virtual bool scrollbarsCanBeActive() const OVERRIDE;
    virtual IntRect scrollableAreaBoundingBox() const OVERRIDE;
    virtual bool userInputScrollable(ScrollbarOrientation) const OVERRIDE;
    virtual int pageStep(ScrollbarOrientation) const OVERRIDE;

    int scrollXOffset() const { return m_scrollOffset.width() + scrollOrigin().x(); }
    int scrollYOffset() const { return m_scrollOffset.height() + scrollOrigin().y(); }

    IntSize scrollOffset() const { return m_scrollOffset; }

    // FIXME: We shouldn't allow access to m_overflowRect outside this class.
    LayoutRect overflowRect() const { return m_overflowRect; }

    void scrollToOffset(const IntSize& scrollOffset, ScrollOffsetClamping = ScrollOffsetUnclamped);

    void updateAfterLayout();
    void updateAfterStyleChange(const RenderStyle*);

private:
    bool hasHorizontalOverflow() const;
    bool hasVerticalOverflow() const;
    bool hasScrollableHorizontalOverflow() const;
    bool hasScrollableVerticalOverflow() const;

    int scrollWidth() const;
    int scrollHeight() const;

    void computeScrollDimensions();

    IntSize clampScrollOffset(const IntSize&) const;
    IntSize adjustedScrollOffset() const { return IntSize(scrollXOffset(), scrollYOffset()); }

    void setScrollOffset(const IntSize& scrollOffset) { m_scrollOffset = scrollOffset; }

    RenderLayerModelObject* renderer() const;

    RenderLayer* m_layer;

    unsigned m_scrollDimensionsDirty : 1;

    // The width/height of our scrolled area.
    LayoutRect m_overflowRect;

    // This is the (scroll) offset from scrollOrigin().
    IntSize m_scrollOffset;
};

} // Namespace WebCore

#endif // RenderLayerScrollableArea_h