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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/rendering/RenderObject.h"
     30 #include "platform/geometry/FloatPoint.h"
     31 #include "platform/geometry/FloatQuad.h"
     32 #include "platform/geometry/IntSize.h"
     33 #include "platform/geometry/LayoutSize.h"
     34 #include "platform/transforms/TransformationMatrix.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_offsetForFixedPosition(o.m_offsetForFixedPosition)
     50         , m_accumulatingTransform(o.m_accumulatingTransform)
     51         , m_isNonUniform(o.m_isNonUniform)
     52         , m_isFixedPosition(o.m_isFixedPosition)
     53         , m_hasTransform(o.m_hasTransform)
     54     {
     55         ASSERT(!o.m_transform);
     56     }
     57     RenderGeometryMapStep(const RenderObject* renderer, bool accumulatingTransform, bool isNonUniform, bool isFixedPosition, bool hasTransform)
     58         : m_renderer(renderer)
     59         , m_accumulatingTransform(accumulatingTransform)
     60         , m_isNonUniform(isNonUniform)
     61         , m_isFixedPosition(isFixedPosition)
     62         , m_hasTransform(hasTransform)
     63     {
     64     }
     65     const RenderObject* m_renderer;
     66     LayoutSize m_offset;
     67     OwnPtr<TransformationMatrix> m_transform; // Includes offset if non-null.
     68     LayoutSize m_offsetForFixedPosition;
     69     bool m_accumulatingTransform;
     70     bool m_isNonUniform; // Mapping depends on the input point, e.g. because of CSS columns.
     71     bool m_isFixedPosition;
     72     bool m_hasTransform;
     73 };
     74 
     75 // Can be used while walking the Renderer tree to cache data about offsets and transforms.
     76 class RenderGeometryMap {
     77     WTF_MAKE_NONCOPYABLE(RenderGeometryMap);
     78 public:
     79     RenderGeometryMap(MapCoordinatesFlags = UseTransforms);
     80     ~RenderGeometryMap();
     81 
     82     MapCoordinatesFlags mapCoordinatesFlags() const { return m_mapCoordinatesFlags; }
     83 
     84     FloatPoint absolutePoint(const FloatPoint& p) const
     85     {
     86         return mapToContainer(p, 0);
     87     }
     88 
     89     FloatRect absoluteRect(const FloatRect& rect) const
     90     {
     91         return mapToContainer(rect, 0).boundingBox();
     92     }
     93 
     94     // Map to a container. Will assert that the container has been pushed onto this map.
     95     // A null container maps through the RenderView (including its scale transform, if any).
     96     // If the container is the RenderView, the scroll offset is applied, but not the scale.
     97     FloatPoint mapToContainer(const FloatPoint&, const RenderLayerModelObject*) const;
     98     FloatQuad mapToContainer(const FloatRect&, const RenderLayerModelObject*) const;
     99 
    100     // Called by code walking the renderer or layer trees.
    101     void pushMappingsToAncestor(const RenderLayer*, const RenderLayer* ancestorLayer);
    102     void popMappingsToAncestor(const RenderLayer*);
    103     void pushMappingsToAncestor(const RenderObject*, const RenderLayerModelObject* ancestorRenderer);
    104     void popMappingsToAncestor(const RenderLayerModelObject*);
    105 
    106     // The following methods should only be called by renderers inside a call to pushMappingsToAncestor().
    107 
    108     // Push geometry info between this renderer and some ancestor. The ancestor must be its container() or some
    109     // stacking context between the renderer and its container.
    110     void push(const RenderObject*, const LayoutSize&, bool accumulatingTransform = false, bool isNonUniform = false, bool isFixedPosition = false, bool hasTransform = false, LayoutSize offsetForFixedPosition = LayoutSize());
    111     void push(const RenderObject*, const TransformationMatrix&, bool accumulatingTransform = false, bool isNonUniform = false, bool isFixedPosition = false, bool hasTransform = false, LayoutSize offsetForFixedPosition = LayoutSize());
    112 
    113 private:
    114     void mapToContainer(TransformState&, const RenderLayerModelObject* container = 0) const;
    115 
    116     void stepInserted(const RenderGeometryMapStep&);
    117     void stepRemoved(const RenderGeometryMapStep&);
    118 
    119     bool hasNonUniformStep() const { return m_nonUniformStepsCount; }
    120     bool hasTransformStep() const { return m_transformedStepsCount; }
    121     bool hasFixedPositionStep() const { return m_fixedStepsCount; }
    122 
    123 #ifndef NDEBUG
    124     void dumpSteps();
    125 #endif
    126 
    127 #if !ASSERT_DISABLED
    128     bool isTopmostRenderView(const RenderObject* renderer) const;
    129 #endif
    130 
    131     typedef Vector<RenderGeometryMapStep, 32> RenderGeometryMapSteps;
    132 
    133     size_t m_insertionPosition;
    134     int m_nonUniformStepsCount;
    135     int m_transformedStepsCount;
    136     int m_fixedStepsCount;
    137     RenderGeometryMapSteps m_mapping;
    138     LayoutSize m_accumulatedOffset;
    139     MapCoordinatesFlags m_mapCoordinatesFlags;
    140 };
    141 
    142 } // namespace WebCore
    143 
    144 namespace WTF {
    145 // This is required for a struct with OwnPtr. We know RenderGeometryMapStep is simple enough that
    146 // initializing to 0 and moving with memcpy (and then not destructing the original) will work.
    147 template<> struct VectorTraits<WebCore::RenderGeometryMapStep> : SimpleClassVectorTraits { };
    148 }
    149 
    150 #endif // RenderGeometryMap_h
    151