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      1 /*
      2  * Copyright (C) 2012 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 COMPUTER, 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 COMPUTER, 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 RenderGeometryMap_h
     27 #define RenderGeometryMap_h
     28 
     29 #include "core/platform/graphics/FloatPoint.h"
     30 #include "core/platform/graphics/FloatQuad.h"
     31 #include "core/platform/graphics/IntSize.h"
     32 #include "core/platform/graphics/LayoutSize.h"
     33 #include "core/platform/graphics/transforms/TransformationMatrix.h"
     34 #include "core/rendering/RenderObject.h"
     35 #include "wtf/OwnPtr.h"
     36 
     37 namespace WebCore {
     38 
     39 class RenderLayer;
     40 class RenderLayerModelObject;
     41 class RenderView;
     42 class TransformState;
     43 
     44 // Stores data about how to map from one renderer to its container.
     45 struct RenderGeometryMapStep {
     46     RenderGeometryMapStep(const RenderGeometryMapStep& o)
     47         : m_renderer(o.m_renderer)
     48         , m_offset(o.m_offset)
     49         , m_accumulatingTransform(o.m_accumulatingTransform)
     50         , m_isNonUniform(o.m_isNonUniform)
     51         , m_isFixedPosition(o.m_isFixedPosition)
     52         , m_hasTransform(o.m_hasTransform)
     53     {
     54         ASSERT(!o.m_transform);
     55     }
     56     RenderGeometryMapStep(const RenderObject* renderer, bool accumulatingTransform, bool isNonUniform, bool isFixedPosition, bool hasTransform)
     57         : m_renderer(renderer)
     58         , m_accumulatingTransform(accumulatingTransform)
     59         , m_isNonUniform(isNonUniform)
     60         , m_isFixedPosition(isFixedPosition)
     61         , m_hasTransform(hasTransform)
     62     {
     63     }
     64     const RenderObject* m_renderer;
     65     LayoutSize m_offset;
     66     OwnPtr<TransformationMatrix> m_transform; // Includes offset if non-null.
     67     bool m_accumulatingTransform;
     68     bool m_isNonUniform; // Mapping depends on the input point, e.g. because of CSS columns.
     69     bool m_isFixedPosition;
     70     bool m_hasTransform;
     71 };
     72 
     73 // Can be used while walking the Renderer tree to cache data about offsets and transforms.
     74 class RenderGeometryMap {
     75     WTF_MAKE_NONCOPYABLE(RenderGeometryMap);
     76 public:
     77     RenderGeometryMap(MapCoordinatesFlags = UseTransforms);
     78     ~RenderGeometryMap();
     79 
     80     MapCoordinatesFlags mapCoordinatesFlags() const { return m_mapCoordinatesFlags; }
     81 
     82     FloatPoint absolutePoint(const FloatPoint& p) const
     83     {
     84         return mapToContainer(p, 0);
     85     }
     86 
     87     FloatRect absoluteRect(const FloatRect& rect) const
     88     {
     89         return mapToContainer(rect, 0).boundingBox();
     90     }
     91 
     92     // Map to a container. Will assert that the container has been pushed onto this map.
     93     // A null container maps through the RenderView (including its scale transform, if any).
     94     // If the container is the RenderView, the scroll offset is applied, but not the scale.
     95     FloatPoint mapToContainer(const FloatPoint&, const RenderLayerModelObject*) const;
     96     FloatQuad mapToContainer(const FloatRect&, const RenderLayerModelObject*) const;
     97 
     98     // Called by code walking the renderer or layer trees.
     99     void pushMappingsToAncestor(const RenderLayer*, const RenderLayer* ancestorLayer);
    100     void popMappingsToAncestor(const RenderLayer*);
    101     void pushMappingsToAncestor(const RenderObject*, const RenderLayerModelObject* ancestorRenderer);
    102     void popMappingsToAncestor(const RenderLayerModelObject*);
    103 
    104     // The following methods should only be called by renderers inside a call to pushMappingsToAncestor().
    105 
    106     // Push geometry info between this renderer and some ancestor. The ancestor must be its container() or some
    107     // stacking context between the renderer and its container.
    108     void push(const RenderObject*, const LayoutSize&, bool accumulatingTransform = false, bool isNonUniform = false, bool isFixedPosition = false, bool hasTransform = false);
    109     void push(const RenderObject*, const TransformationMatrix&, bool accumulatingTransform = false, bool isNonUniform = false, bool isFixedPosition = false, bool hasTransform = false);
    110 
    111     // RenderView gets special treatment, because it applies the scroll offset only for elements inside in fixed position.
    112     void pushView(const RenderView*, const LayoutSize& scrollOffset, const TransformationMatrix* = 0);
    113 
    114 private:
    115     void mapToContainer(TransformState&, const RenderLayerModelObject* container = 0) const;
    116 
    117     void stepInserted(const RenderGeometryMapStep&);
    118     void stepRemoved(const RenderGeometryMapStep&);
    119 
    120     bool hasNonUniformStep() const { return m_nonUniformStepsCount; }
    121     bool hasTransformStep() const { return m_transformedStepsCount; }
    122     bool hasFixedPositionStep() const { return m_fixedStepsCount; }
    123 
    124     typedef Vector<RenderGeometryMapStep, 32> RenderGeometryMapSteps;
    125 
    126     size_t m_insertionPosition;
    127     int m_nonUniformStepsCount;
    128     int m_transformedStepsCount;
    129     int m_fixedStepsCount;
    130     RenderGeometryMapSteps m_mapping;
    131     LayoutSize m_accumulatedOffset;
    132     MapCoordinatesFlags m_mapCoordinatesFlags;
    133 };
    134 
    135 } // namespace WebCore
    136 
    137 namespace WTF {
    138 // This is required for a struct with OwnPtr. We know RenderGeometryMapStep is simple enough that
    139 // initializing to 0 and moving with memcpy (and then not destructing the original) will work.
    140 template<> struct VectorTraits<WebCore::RenderGeometryMapStep> : SimpleClassVectorTraits { };
    141 }
    142 
    143 #endif // RenderGeometryMap_h
    144