third_party/WebKit/Source/core/layout/LayoutGeometryMap.h

/*
 * 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 COMPUTER, 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 COMPUTER, 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.
 */

#ifndef LayoutGeometryMap_h
#define LayoutGeometryMap_h

#include "core/CoreExport.h"
#include "core/layout/LayoutGeometryMapStep.h"
#include "core/layout/LayoutObject.h"
#include "platform/geometry/FloatPoint.h"
#include "platform/geometry/FloatQuad.h"
#include "platform/geometry/IntSize.h"
#include "platform/geometry/LayoutSize.h"
#include "wtf/Allocator.h"
#include "wtf/OwnPtr.h"

namespace blink {

class PaintLayer;
class LayoutBoxModelObject;
class TransformationMatrix;
class TransformState;

// Can be used while walking the layout tree to cache data about offsets and transforms.
class CORE_EXPORT LayoutGeometryMap {
    DISALLOW_NEW();
    WTF_MAKE_NONCOPYABLE(LayoutGeometryMap);
public:
    LayoutGeometryMap(MapCoordinatesFlags = UseTransforms);
    ~LayoutGeometryMap();

    MapCoordinatesFlags mapCoordinatesFlags() const { return m_mapCoordinatesFlags; }

    FloatRect absoluteRect(const FloatRect& rect) const
    {
        return mapToContainer(rect, 0).boundingBox();
    }

    // Map to a container. Will assert that the container has been pushed onto this map.
    // A null container maps through the LayoutView (including its scale transform, if any).
    // If the container is the LayoutView, the scroll offset is applied, but not the scale.
    FloatQuad mapToContainer(const FloatRect&, const LayoutBoxModelObject*) const;

    // Called by code walking the layout or layer trees.
    void pushMappingsToAncestor(const PaintLayer*, const PaintLayer* ancestorLayer);
    void popMappingsToAncestor(const PaintLayer*);
    void pushMappingsToAncestor(const LayoutObject*, const LayoutBoxModelObject* ancestorLayoutObject);

    // The following methods should only be called by layoutObjects inside a call to pushMappingsToAncestor().

    // Push geometry info between this layoutObject and some ancestor. The ancestor must be its container() or some
    // stacking context between the layoutObject and its container.
    void push(const LayoutObject*, const LayoutSize&, bool accumulatingTransform = false, bool isNonUniform = false, bool isFixedPosition = false, bool hasTransform = false, LayoutSize offsetForFixedPosition = LayoutSize());
    void push(const LayoutObject*, const TransformationMatrix&, bool accumulatingTransform = false, bool isNonUniform = false, bool isFixedPosition = false, bool hasTransform = false, LayoutSize offsetForFixedPosition = LayoutSize());

private:
    void popMappingsToAncestor(const LayoutBoxModelObject*);
    void mapToContainer(TransformState&, const LayoutBoxModelObject* container = nullptr) const;

    void stepInserted(const LayoutGeometryMapStep&);
    void stepRemoved(const LayoutGeometryMapStep&);

    bool hasNonUniformStep() const { return m_nonUniformStepsCount; }
    bool hasTransformStep() const { return m_transformedStepsCount; }
    bool hasFixedPositionStep() const { return m_fixedStepsCount; }

#ifndef NDEBUG
    void dumpSteps() const;
#endif

#if ENABLE(ASSERT)
    bool isTopmostLayoutView(const LayoutObject*) const;
#endif

    typedef Vector<LayoutGeometryMapStep, 32> LayoutGeometryMapSteps;

    size_t m_insertionPosition;
    int m_nonUniformStepsCount;
    int m_transformedStepsCount;
    int m_fixedStepsCount;
    LayoutGeometryMapSteps m_mapping;
    LayoutSize m_accumulatedOffset;
    MapCoordinatesFlags m_mapCoordinatesFlags;
};

} // namespace blink

#endif // LayoutGeometryMap_h