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/*
* Copyright (C) 2012 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. AND ITS CONTRIBUTORS ``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 ITS 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.
*/
#ifndef ScrollingConstraints_h
#define ScrollingConstraints_h
#include "FloatRect.h"
namespace WebCore {
// ViewportConstraints classes encapsulate data and logic required to reposition elements whose layout
// depends on the viewport rect (positions fixed and sticky), when scrolling and zooming.
class ViewportConstraints {
public:
enum ConstraintType {
FixedPositionConstaint,
StickyPositionConstraint
};
enum AnchorEdgeFlags {
AnchorEdgeLeft = 1 << 0,
AnchorEdgeRight = 1 << 1,
AnchorEdgeTop = 1 << 2,
AnchorEdgeBottom = 1 << 3
};
typedef unsigned AnchorEdges;
virtual ~ViewportConstraints() { }
virtual ConstraintType constraintType() const = 0;
AnchorEdges anchorEdges() const { return m_anchorEdges; }
bool hasAnchorEdge(AnchorEdgeFlags flag) const { return m_anchorEdges & flag; }
void addAnchorEdge(AnchorEdgeFlags edgeFlag) { m_anchorEdges |= edgeFlag; }
void setAnchorEdges(AnchorEdges edges) { m_anchorEdges = edges; }
FloatSize alignmentOffset() const { return m_alignmentOffset; }
void setAlignmentOffset(const FloatSize& offset) { m_alignmentOffset = offset; }
protected:
ViewportConstraints()
: m_anchorEdges(0)
{ }
FloatSize m_alignmentOffset;
AnchorEdges m_anchorEdges;
};
class FixedPositionViewportConstraints : public ViewportConstraints {
public:
FloatPoint layerPositionForViewportRect(const FloatRect& viewportRect) const;
const FloatRect& viewportRectAtLastLayout() const { return m_viewportRectAtLastLayout; }
void setViewportRectAtLastLayout(const FloatRect& rect) { m_viewportRectAtLastLayout = rect; }
const FloatPoint& layerPositionAtLastLayout() const { return m_layerPositionAtLastLayout; }
void setLayerPositionAtLastLayout(const FloatPoint& point) { m_layerPositionAtLastLayout = point; }
bool operator==(const FixedPositionViewportConstraints& other) const
{
return m_alignmentOffset == other.m_alignmentOffset
&& m_anchorEdges == other.m_anchorEdges
&& m_viewportRectAtLastLayout == other.m_viewportRectAtLastLayout
&& m_layerPositionAtLastLayout == other.m_layerPositionAtLastLayout;
}
bool operator!=(const FixedPositionViewportConstraints& other) const { return !(*this == other); }
private:
virtual ConstraintType constraintType() const OVERRIDE { return FixedPositionConstaint; };
FloatRect m_viewportRectAtLastLayout;
FloatPoint m_layerPositionAtLastLayout;
};
class StickyPositionViewportConstraints : public ViewportConstraints {
public:
StickyPositionViewportConstraints()
: m_leftOffset(0)
, m_rightOffset(0)
, m_topOffset(0)
, m_bottomOffset(0)
{ }
FloatSize computeStickyOffset(const FloatRect& viewportRect) const;
const FloatSize stickyOffsetAtLastLayout() const { return m_stickyOffsetAtLastLayout; }
void setStickyOffsetAtLastLayout(const FloatSize& offset) { m_stickyOffsetAtLastLayout = offset; }
FloatPoint layerPositionForViewportRect(const FloatRect& viewportRect) const;
const FloatPoint& layerPositionAtLastLayout() const { return m_layerPositionAtLastLayout; }
void setLayerPositionAtLastLayout(const FloatPoint& point) { m_layerPositionAtLastLayout = point; }
float leftOffset() const { return m_leftOffset; }
float rightOffset() const { return m_rightOffset; }
float topOffset() const { return m_topOffset; }
float bottomOffset() const { return m_bottomOffset; }
void setLeftOffset(float offset) { m_leftOffset = offset; }
void setRightOffset(float offset) { m_rightOffset = offset; }
void setTopOffset(float offset) { m_topOffset = offset; }
void setBottomOffset(float offset) { m_bottomOffset = offset; }
void setAbsoluteContainingBlockRect(const FloatRect& rect) { m_absoluteContainingBlockRect = rect; }
void setAbsoluteStickyBoxRect(const FloatRect& rect) { m_absoluteStickyBoxRect = rect; }
private:
virtual ConstraintType constraintType() const OVERRIDE { return StickyPositionConstraint; };
float m_leftOffset;
float m_rightOffset;
float m_topOffset;
float m_bottomOffset;
FloatRect m_absoluteContainingBlockRect;
FloatRect m_absoluteStickyBoxRect;
FloatSize m_stickyOffsetAtLastLayout;
FloatPoint m_layerPositionAtLastLayout;
};
} // namespace WebCore
#endif // ScrollingConstraints_h
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