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      1 /*
      2  * Copyright (C) 2007 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 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 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 LayoutState_h
     27 #define LayoutState_h
     28 
     29 #include "core/rendering/ColumnInfo.h"
     30 #include "platform/geometry/LayoutRect.h"
     31 #include "wtf/HashMap.h"
     32 #include "wtf/Noncopyable.h"
     33 
     34 namespace blink {
     35 
     36 class ForceHorriblySlowRectMapping;
     37 class RenderBox;
     38 class RenderObject;
     39 class RenderInline;
     40 class RenderView;
     41 
     42 class LayoutState {
     43     WTF_MAKE_NONCOPYABLE(LayoutState);
     44 public:
     45     // Constructor for root LayoutState created by RenderView
     46     LayoutState(LayoutUnit pageLogicalHeight, bool pageLogicalHeightChanged, RenderView&);
     47     // Constructor for sub-tree Layout and RenderTableSections
     48     explicit LayoutState(RenderObject& root);
     49 
     50     LayoutState(RenderBox&, const LayoutSize& offset, LayoutUnit pageLogicalHeight = 0, bool pageHeightLogicalChanged = false, ColumnInfo* = 0, bool containingBlockLogicalWidthChanged = false);
     51     LayoutState(RenderInline&);
     52 
     53     ~LayoutState();
     54 
     55     void clearPaginationInformation();
     56     bool isPaginatingColumns() const { return m_columnInfo; }
     57     bool isPaginated() const { return m_isPaginated; }
     58 
     59     // The page logical offset is the object's offset from the top of the page in the page progression
     60     // direction (so an x-offset in vertical text and a y-offset for horizontal text).
     61     LayoutUnit pageLogicalOffset(const RenderBox&, const LayoutUnit& childLogicalOffset) const;
     62 
     63     void addForcedColumnBreak(const RenderBox&, const LayoutUnit& childLogicalOffset);
     64 
     65     void setColumnInfo(ColumnInfo* columnInfo) { m_columnInfo = columnInfo; }
     66 
     67     const LayoutSize& layoutOffset() const { return m_layoutOffset; }
     68     const LayoutSize& pageOffset() const { return m_pageOffset; }
     69     LayoutUnit pageLogicalHeight() const { return m_pageLogicalHeight; }
     70     bool pageLogicalHeightChanged() const { return m_pageLogicalHeightChanged; }
     71     bool containingBlockLogicalWidthChanged() const { return m_containingBlockLogicalWidthChanged; }
     72 
     73     LayoutState* next() const { return m_next; }
     74 
     75     bool needsBlockDirectionLocationSetBeforeLayout() const { return m_isPaginated && m_pageLogicalHeight; }
     76 
     77     ColumnInfo* columnInfo() const { return m_columnInfo; }
     78 
     79     RenderObject& renderer() const { return m_renderer; }
     80 
     81 private:
     82     friend class ForceHorriblySlowRectMapping;
     83 
     84     // Do not add anything apart from bitfields until after m_columnInfo. See https://bugs.webkit.org/show_bug.cgi?id=100173
     85     bool m_isPaginated : 1;
     86     // If our page height has changed, this will force all blocks to relayout.
     87     bool m_pageLogicalHeightChanged : 1;
     88     bool m_containingBlockLogicalWidthChanged : 1;
     89 
     90     // If the enclosing pagination model is a column model, then this will store column information for easy retrieval/manipulation.
     91     ColumnInfo* m_columnInfo;
     92     LayoutState* m_next;
     93 
     94     // x/y offset from container. Does not include relative positioning or scroll offsets.
     95     LayoutSize m_layoutOffset;
     96 
     97     // The current page height for the pagination model that encloses us.
     98     LayoutUnit m_pageLogicalHeight;
     99     // The offset of the start of the first page in the nearest enclosing pagination model.
    100     LayoutSize m_pageOffset;
    101 
    102     RenderObject& m_renderer;
    103 };
    104 
    105 } // namespace blink
    106 
    107 #endif // LayoutState_h
    108