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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 #include "config.h"
     27 #include "LayoutState.h"
     28 
     29 #include "ColumnInfo.h"
     30 #include "RenderArena.h"
     31 #include "RenderInline.h"
     32 #include "RenderLayer.h"
     33 #include "RenderView.h"
     34 
     35 namespace WebCore {
     36 
     37 LayoutState::LayoutState(LayoutState* prev, RenderBox* renderer, const IntSize& offset, int pageLogicalHeight, bool pageLogicalHeightChanged, ColumnInfo* columnInfo)
     38     : m_columnInfo(columnInfo)
     39     , m_next(prev)
     40 #ifndef NDEBUG
     41     , m_renderer(renderer)
     42 #endif
     43 {
     44     ASSERT(m_next);
     45 
     46     bool fixed = renderer->isPositioned() && renderer->style()->position() == FixedPosition;
     47     if (fixed) {
     48         // FIXME: This doesn't work correctly with transforms.
     49         FloatPoint fixedOffset = renderer->view()->localToAbsolute(FloatPoint(), true);
     50         m_paintOffset = IntSize(fixedOffset.x(), fixedOffset.y()) + offset;
     51     } else
     52         m_paintOffset = prev->m_paintOffset + offset;
     53 
     54     if (renderer->isPositioned() && !fixed) {
     55         if (RenderObject* container = renderer->container()) {
     56             if (container->isRelPositioned() && container->isRenderInline())
     57                 m_paintOffset += toRenderInline(container)->relativePositionedInlineOffset(renderer);
     58         }
     59     }
     60 
     61     m_layoutOffset = m_paintOffset;
     62 
     63     if (renderer->isRelPositioned() && renderer->hasLayer())
     64         m_paintOffset += renderer->layer()->relativePositionOffset();
     65 
     66     m_clipped = !fixed && prev->m_clipped;
     67     if (m_clipped)
     68         m_clipRect = prev->m_clipRect;
     69 
     70     if (renderer->hasOverflowClip()) {
     71         RenderLayer* layer = renderer->layer();
     72         IntRect clipRect(toPoint(m_paintOffset) + renderer->view()->layoutDelta(), layer->size());
     73         if (m_clipped)
     74             m_clipRect.intersect(clipRect);
     75         else {
     76             m_clipRect = clipRect;
     77             m_clipped = true;
     78         }
     79 
     80         m_paintOffset -= layer->scrolledContentOffset();
     81     }
     82 
     83     // If we establish a new page height, then cache the offset to the top of the first page.
     84     // We can compare this later on to figure out what part of the page we're actually on,
     85     if (pageLogicalHeight || m_columnInfo) {
     86         m_pageLogicalHeight = pageLogicalHeight;
     87         m_pageOffset = IntSize(m_layoutOffset.width() + renderer->borderLeft() + renderer->paddingLeft(),
     88                                m_layoutOffset.height() + renderer->borderTop() + renderer->paddingTop());
     89         m_pageLogicalHeightChanged = pageLogicalHeightChanged;
     90     } else {
     91         // If we don't establish a new page height, then propagate the old page height and offset down.
     92         m_pageLogicalHeight = m_next->m_pageLogicalHeight;
     93         m_pageLogicalHeightChanged = m_next->m_pageLogicalHeightChanged;
     94         m_pageOffset = m_next->m_pageOffset;
     95 
     96         // Disable pagination for objects we don't support.  For now this includes overflow:scroll/auto and inline blocks.
     97         if (renderer->isReplaced() || renderer->scrollsOverflow())
     98             m_pageLogicalHeight = 0;
     99     }
    100 
    101     if (!m_columnInfo)
    102         m_columnInfo = m_next->m_columnInfo;
    103 
    104     m_layoutDelta = m_next->m_layoutDelta;
    105 
    106     // FIXME: <http://bugs.webkit.org/show_bug.cgi?id=13443> Apply control clip if present.
    107 }
    108 
    109 LayoutState::LayoutState(RenderObject* root)
    110     : m_clipped(false)
    111     , m_pageLogicalHeight(0)
    112     , m_pageLogicalHeightChanged(false)
    113     , m_columnInfo(0)
    114     , m_next(0)
    115 #ifndef NDEBUG
    116     , m_renderer(root)
    117 #endif
    118 {
    119     RenderObject* container = root->container();
    120     FloatPoint absContentPoint = container->localToAbsolute(FloatPoint(), false, true);
    121     m_paintOffset = IntSize(absContentPoint.x(), absContentPoint.y());
    122 
    123     if (container->hasOverflowClip()) {
    124         RenderLayer* layer = toRenderBoxModelObject(container)->layer();
    125         m_clipped = true;
    126         m_clipRect = IntRect(toPoint(m_paintOffset), layer->size());
    127         m_paintOffset -= layer->scrolledContentOffset();
    128     }
    129 }
    130 
    131 #ifndef NDEBUG
    132 static bool inLayoutStateDestroy;
    133 #endif
    134 
    135 void LayoutState::destroy(RenderArena* renderArena)
    136 {
    137 #ifndef NDEBUG
    138     inLayoutStateDestroy = true;
    139 #endif
    140     delete this;
    141 #ifndef NDEBUG
    142     inLayoutStateDestroy = false;
    143 #endif
    144     renderArena->free(*(size_t*)this, this);
    145 }
    146 
    147 void* LayoutState::operator new(size_t sz, RenderArena* renderArena) throw()
    148 {
    149     return renderArena->allocate(sz);
    150 }
    151 
    152 void LayoutState::operator delete(void* ptr, size_t sz)
    153 {
    154     ASSERT(inLayoutStateDestroy);
    155     *(size_t*)ptr = sz;
    156 }
    157 
    158 void LayoutState::clearPaginationInformation()
    159 {
    160     m_pageLogicalHeight = m_next->m_pageLogicalHeight;
    161     m_pageOffset = m_next->m_pageOffset;
    162     m_columnInfo = m_next->m_columnInfo;
    163 }
    164 
    165 int LayoutState::pageLogicalOffset(int childLogicalOffset) const
    166 {
    167     return m_layoutOffset.height() + childLogicalOffset - m_pageOffset.height();
    168 }
    169 
    170 void LayoutState::addForcedColumnBreak(int childLogicalOffset)
    171 {
    172     if (!m_columnInfo || m_columnInfo->columnHeight())
    173         return;
    174     m_columnInfo->addForcedBreak(pageLogicalOffset(childLogicalOffset));
    175 }
    176 
    177 } // namespace WebCore
    178