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      1 /*
      2  * Copyright (C) 1999 Lars Knoll (knoll (at) kde.org)
      3  *           (C) 1999 Antti Koivisto (koivisto (at) kde.org)
      4  * Copyright (C) 2003, 2006, 2007 Apple Inc. All rights reserved.
      5  *
      6  * This library is free software; you can redistribute it and/or
      7  * modify it under the terms of the GNU Library General Public
      8  * License as published by the Free Software Foundation; either
      9  * version 2 of the License, or (at your option) any later version.
     10  *
     11  * This library is distributed in the hope that it will be useful,
     12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
     13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
     14  * Library General Public License for more details.
     15  *
     16  * You should have received a copy of the GNU Library General Public License
     17  * along with this library; see the file COPYING.LIB.  If not, write to
     18  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
     19  * Boston, MA 02110-1301, USA.
     20  *
     21  */
     22 
     23 #ifndef RenderBox_h
     24 #define RenderBox_h
     25 
     26 #include "core/rendering/RenderBoxModelObject.h"
     27 #include "core/rendering/RenderOverflow.h"
     28 #include "core/rendering/shapes/ShapeOutsideInfo.h"
     29 #include "platform/scroll/ScrollTypes.h"
     30 
     31 namespace blink {
     32 
     33 struct PaintInfo;
     34 
     35 enum SizeType { MainOrPreferredSize, MinSize, MaxSize };
     36 enum AvailableLogicalHeightType { ExcludeMarginBorderPadding, IncludeMarginBorderPadding };
     37 enum OverlayScrollbarSizeRelevancy { IgnoreOverlayScrollbarSize, IncludeOverlayScrollbarSize };
     38 enum MarginDirection { BlockDirection, InlineDirection };
     39 
     40 enum ShouldComputePreferred { ComputeActual, ComputePreferred };
     41 
     42 enum ContentsClipBehavior { ForceContentsClip, SkipContentsClipIfPossible };
     43 
     44 enum ScrollOffsetClamping {
     45     ScrollOffsetUnclamped,
     46     ScrollOffsetClamped
     47 };
     48 
     49 struct RenderBoxRareData {
     50     WTF_MAKE_NONCOPYABLE(RenderBoxRareData); WTF_MAKE_FAST_ALLOCATED;
     51 public:
     52     RenderBoxRareData()
     53         : m_inlineBoxWrapper(0)
     54         , m_overrideLogicalContentHeight(-1)
     55         , m_overrideLogicalContentWidth(-1)
     56         , m_previousBorderBoxSize(-1, -1)
     57     {
     58     }
     59 
     60     // For inline replaced elements, the inline box that owns us.
     61     InlineBox* m_inlineBoxWrapper;
     62 
     63     LayoutUnit m_overrideLogicalContentHeight;
     64     LayoutUnit m_overrideLogicalContentWidth;
     65 
     66     // Set by RenderBox::updatePreviousBorderBoxSizeIfNeeded().
     67     LayoutSize m_previousBorderBoxSize;
     68 };
     69 
     70 class RenderBox : public RenderBoxModelObject {
     71 public:
     72     explicit RenderBox(ContainerNode*);
     73 
     74     // hasAutoZIndex only returns true if the element is positioned or a flex-item since
     75     // position:static elements that are not flex-items get their z-index coerced to auto.
     76     virtual LayerType layerTypeRequired() const OVERRIDE
     77     {
     78         if (isPositioned() || createsGroup() || hasClipPath() || hasTransform() || hasHiddenBackface() || hasReflection() || style()->specifiesColumns() || !style()->hasAutoZIndex() || style()->shouldCompositeForCurrentAnimations())
     79             return NormalLayer;
     80         if (hasOverflowClip())
     81             return OverflowClipLayer;
     82 
     83         return NoLayer;
     84     }
     85 
     86     virtual bool backgroundIsKnownToBeOpaqueInRect(const LayoutRect& localRect) const OVERRIDE;
     87 
     88     // Use this with caution! No type checking is done!
     89     RenderBox* firstChildBox() const;
     90     RenderBox* lastChildBox() const;
     91 
     92     LayoutUnit x() const { return m_frameRect.x(); }
     93     LayoutUnit y() const { return m_frameRect.y(); }
     94     LayoutUnit width() const { return m_frameRect.width(); }
     95     LayoutUnit height() const { return m_frameRect.height(); }
     96 
     97     int pixelSnappedWidth() const { return m_frameRect.pixelSnappedWidth(); }
     98     int pixelSnappedHeight() const { return m_frameRect.pixelSnappedHeight(); }
     99 
    100     // These represent your location relative to your container as a physical offset.
    101     // In layout related methods you almost always want the logical location (e.g. x() and y()).
    102     LayoutUnit top() const { return topLeftLocation().y(); }
    103     LayoutUnit left() const { return topLeftLocation().x(); }
    104 
    105     void setX(LayoutUnit x) { m_frameRect.setX(x); }
    106     void setY(LayoutUnit y) { m_frameRect.setY(y); }
    107     void setWidth(LayoutUnit width) { m_frameRect.setWidth(width); }
    108     void setHeight(LayoutUnit height) { m_frameRect.setHeight(height); }
    109 
    110     LayoutUnit logicalLeft() const { return style()->isHorizontalWritingMode() ? x() : y(); }
    111     LayoutUnit logicalRight() const { return logicalLeft() + logicalWidth(); }
    112     LayoutUnit logicalTop() const { return style()->isHorizontalWritingMode() ? y() : x(); }
    113     LayoutUnit logicalBottom() const { return logicalTop() + logicalHeight(); }
    114     LayoutUnit logicalWidth() const { return style()->isHorizontalWritingMode() ? width() : height(); }
    115     LayoutUnit logicalHeight() const { return style()->isHorizontalWritingMode() ? height() : width(); }
    116 
    117     LayoutUnit constrainLogicalWidthByMinMax(LayoutUnit, LayoutUnit, RenderBlock*) const;
    118     LayoutUnit constrainLogicalHeightByMinMax(LayoutUnit logicalHeight, LayoutUnit intrinsicContentHeight) const;
    119     LayoutUnit constrainContentBoxLogicalHeightByMinMax(LayoutUnit logicalHeight, LayoutUnit intrinsicContentHeight) const;
    120 
    121     int pixelSnappedLogicalHeight() const { return style()->isHorizontalWritingMode() ? pixelSnappedHeight() : pixelSnappedWidth(); }
    122     int pixelSnappedLogicalWidth() const { return style()->isHorizontalWritingMode() ? pixelSnappedWidth() : pixelSnappedHeight(); }
    123 
    124     void setLogicalLeft(LayoutUnit left)
    125     {
    126         if (style()->isHorizontalWritingMode())
    127             setX(left);
    128         else
    129             setY(left);
    130     }
    131     void setLogicalTop(LayoutUnit top)
    132     {
    133         if (style()->isHorizontalWritingMode())
    134             setY(top);
    135         else
    136             setX(top);
    137     }
    138     void setLogicalLocation(const LayoutPoint& location)
    139     {
    140         if (style()->isHorizontalWritingMode())
    141             setLocation(location);
    142         else
    143             setLocation(location.transposedPoint());
    144     }
    145     void setLogicalWidth(LayoutUnit size)
    146     {
    147         if (style()->isHorizontalWritingMode())
    148             setWidth(size);
    149         else
    150             setHeight(size);
    151     }
    152     void setLogicalHeight(LayoutUnit size)
    153     {
    154         if (style()->isHorizontalWritingMode())
    155             setHeight(size);
    156         else
    157             setWidth(size);
    158     }
    159     void setLogicalSize(const LayoutSize& size)
    160     {
    161         if (style()->isHorizontalWritingMode())
    162             setSize(size);
    163         else
    164             setSize(size.transposedSize());
    165     }
    166 
    167     LayoutPoint location() const { return m_frameRect.location(); }
    168     LayoutSize locationOffset() const { return LayoutSize(x(), y()); }
    169     LayoutSize size() const { return m_frameRect.size(); }
    170     IntSize pixelSnappedSize() const { return m_frameRect.pixelSnappedSize(); }
    171 
    172     void setLocation(const LayoutPoint& location) { m_frameRect.setLocation(location); }
    173 
    174     void setSize(const LayoutSize& size) { m_frameRect.setSize(size); }
    175     void move(LayoutUnit dx, LayoutUnit dy) { m_frameRect.move(dx, dy); }
    176 
    177     LayoutRect frameRect() const { return m_frameRect; }
    178     IntRect pixelSnappedFrameRect() const { return pixelSnappedIntRect(m_frameRect); }
    179     void setFrameRect(const LayoutRect& rect) { m_frameRect = rect; }
    180 
    181     LayoutRect borderBoxRect() const { return LayoutRect(LayoutPoint(), size()); }
    182     LayoutRect paddingBoxRect() const { return LayoutRect(borderLeft(), borderTop(), contentWidth() + paddingLeft() + paddingRight(), contentHeight() + paddingTop() + paddingBottom()); }
    183     IntRect pixelSnappedBorderBoxRect() const { return IntRect(IntPoint(), m_frameRect.pixelSnappedSize()); }
    184     virtual IntRect borderBoundingBox() const OVERRIDE FINAL { return pixelSnappedBorderBoxRect(); }
    185 
    186     // The content area of the box (excludes padding - and intrinsic padding for table cells, etc... - and border).
    187     LayoutRect contentBoxRect() const { return LayoutRect(borderLeft() + paddingLeft(), borderTop() + paddingTop(), contentWidth(), contentHeight()); }
    188     // The content box in absolute coords. Ignores transforms.
    189     IntRect absoluteContentBox() const;
    190     // The content box converted to absolute coords (taking transforms into account).
    191     FloatQuad absoluteContentQuad() const;
    192 
    193     // This returns the content area of the box (excluding padding and border). The only difference with contentBoxRect is that computedCSSContentBoxRect
    194     // does include the intrinsic padding in the content box as this is what some callers expect (like getComputedStyle).
    195     LayoutRect computedCSSContentBoxRect() const { return LayoutRect(borderLeft() + computedCSSPaddingLeft(), borderTop() + computedCSSPaddingTop(), clientWidth() - computedCSSPaddingLeft() - computedCSSPaddingRight(), clientHeight() - computedCSSPaddingTop() - computedCSSPaddingBottom()); }
    196 
    197     virtual void addFocusRingRects(Vector<LayoutRect>&, const LayoutPoint& additionalOffset, const RenderLayerModelObject* paintContainer) const OVERRIDE;
    198 
    199     // Use this with caution! No type checking is done!
    200     RenderBox* previousSiblingBox() const;
    201     RenderBox* nextSiblingBox() const;
    202     RenderBox* parentBox() const;
    203 
    204     bool canResize() const;
    205 
    206     // Visual and layout overflow are in the coordinate space of the box.  This means that they aren't purely physical directions.
    207     // For horizontal-tb and vertical-lr they will match physical directions, but for horizontal-bt and vertical-rl, the top/bottom and left/right
    208     // respectively are flipped when compared to their physical counterparts.  For example minX is on the left in vertical-lr,
    209     // but it is on the right in vertical-rl.
    210     LayoutRect noOverflowRect() const;
    211     LayoutRect layoutOverflowRect() const { return m_overflow ? m_overflow->layoutOverflowRect() : noOverflowRect(); }
    212     IntRect pixelSnappedLayoutOverflowRect() const { return pixelSnappedIntRect(layoutOverflowRect()); }
    213     LayoutSize maxLayoutOverflow() const { return LayoutSize(layoutOverflowRect().maxX(), layoutOverflowRect().maxY()); }
    214     LayoutUnit logicalLeftLayoutOverflow() const { return style()->isHorizontalWritingMode() ? layoutOverflowRect().x() : layoutOverflowRect().y(); }
    215     LayoutUnit logicalRightLayoutOverflow() const { return style()->isHorizontalWritingMode() ? layoutOverflowRect().maxX() : layoutOverflowRect().maxY(); }
    216 
    217     virtual LayoutRect visualOverflowRect() const { return m_overflow ? m_overflow->visualOverflowRect() : borderBoxRect(); }
    218     LayoutUnit logicalLeftVisualOverflow() const { return style()->isHorizontalWritingMode() ? visualOverflowRect().x() : visualOverflowRect().y(); }
    219     LayoutUnit logicalRightVisualOverflow() const { return style()->isHorizontalWritingMode() ? visualOverflowRect().maxX() : visualOverflowRect().maxY(); }
    220 
    221     LayoutRect contentsVisualOverflowRect() const { return m_overflow ? m_overflow->contentsVisualOverflowRect() : LayoutRect(); }
    222 
    223     void addLayoutOverflow(const LayoutRect&);
    224     void addVisualOverflow(const LayoutRect&);
    225 
    226     // Clipped by the contents clip, if one exists.
    227     void addContentsVisualOverflow(const LayoutRect&);
    228 
    229     void addVisualEffectOverflow();
    230     LayoutBoxExtent computeVisualEffectOverflowExtent() const;
    231     void addOverflowFromChild(RenderBox* child) { addOverflowFromChild(child, child->locationOffset()); }
    232     void addOverflowFromChild(RenderBox* child, const LayoutSize& delta);
    233     void clearLayoutOverflow();
    234     void clearAllOverflows() { m_overflow.clear(); }
    235 
    236     void updateLayerTransformAfterLayout();
    237 
    238     LayoutUnit contentWidth() const { return clientWidth() - paddingLeft() - paddingRight(); }
    239     LayoutUnit contentHeight() const { return clientHeight() - paddingTop() - paddingBottom(); }
    240     LayoutUnit contentLogicalWidth() const { return style()->isHorizontalWritingMode() ? contentWidth() : contentHeight(); }
    241     LayoutUnit contentLogicalHeight() const { return style()->isHorizontalWritingMode() ? contentHeight() : contentWidth(); }
    242 
    243     // IE extensions. Used to calculate offsetWidth/Height.  Overridden by inlines (RenderFlow)
    244     // to return the remaining width on a given line (and the height of a single line).
    245     virtual LayoutUnit offsetWidth() const OVERRIDE { return width(); }
    246     virtual LayoutUnit offsetHeight() const OVERRIDE { return height(); }
    247 
    248     virtual int pixelSnappedOffsetWidth() const OVERRIDE FINAL;
    249     virtual int pixelSnappedOffsetHeight() const OVERRIDE FINAL;
    250 
    251     // More IE extensions.  clientWidth and clientHeight represent the interior of an object
    252     // excluding border and scrollbar.  clientLeft/Top are just the borderLeftWidth and borderTopWidth.
    253     LayoutUnit clientLeft() const { return borderLeft() + (style()->shouldPlaceBlockDirectionScrollbarOnLogicalLeft() ? verticalScrollbarWidth() : 0); }
    254     LayoutUnit clientTop() const { return borderTop(); }
    255     LayoutUnit clientWidth() const;
    256     LayoutUnit clientHeight() const;
    257     LayoutUnit clientLogicalWidth() const { return style()->isHorizontalWritingMode() ? clientWidth() : clientHeight(); }
    258     LayoutUnit clientLogicalHeight() const { return style()->isHorizontalWritingMode() ? clientHeight() : clientWidth(); }
    259     LayoutUnit clientLogicalBottom() const { return borderBefore() + clientLogicalHeight(); }
    260     LayoutRect clientBoxRect() const { return LayoutRect(clientLeft(), clientTop(), clientWidth(), clientHeight()); }
    261 
    262     int pixelSnappedClientWidth() const;
    263     int pixelSnappedClientHeight() const;
    264 
    265     // scrollWidth/scrollHeight will be the same as clientWidth/clientHeight unless the
    266     // object has overflow:hidden/scroll/auto specified and also has overflow.
    267     // scrollLeft/Top return the current scroll position.  These methods are virtual so that objects like
    268     // textareas can scroll shadow content (but pretend that they are the objects that are
    269     // scrolling).
    270     virtual LayoutUnit scrollLeft() const;
    271     virtual LayoutUnit scrollTop() const;
    272     virtual LayoutUnit scrollWidth() const;
    273     virtual LayoutUnit scrollHeight() const;
    274     int pixelSnappedScrollWidth() const;
    275     int pixelSnappedScrollHeight() const;
    276     virtual void setScrollLeft(LayoutUnit);
    277     virtual void setScrollTop(LayoutUnit);
    278 
    279     void scrollToOffset(const IntSize&);
    280     void scrollByRecursively(const IntSize& delta, ScrollOffsetClamping = ScrollOffsetUnclamped);
    281     void scrollRectToVisible(const LayoutRect&, const ScrollAlignment& alignX, const ScrollAlignment& alignY);
    282 
    283     virtual LayoutUnit marginTop() const OVERRIDE { return m_marginBox.top(); }
    284     virtual LayoutUnit marginBottom() const OVERRIDE { return m_marginBox.bottom(); }
    285     virtual LayoutUnit marginLeft() const OVERRIDE { return m_marginBox.left(); }
    286     virtual LayoutUnit marginRight() const OVERRIDE { return m_marginBox.right(); }
    287     void setMarginTop(LayoutUnit margin) { m_marginBox.setTop(margin); }
    288     void setMarginBottom(LayoutUnit margin) { m_marginBox.setBottom(margin); }
    289     void setMarginLeft(LayoutUnit margin) { m_marginBox.setLeft(margin); }
    290     void setMarginRight(LayoutUnit margin) { m_marginBox.setRight(margin); }
    291 
    292     LayoutUnit marginLogicalLeft() const { return m_marginBox.logicalLeft(style()->writingMode()); }
    293     LayoutUnit marginLogicalRight() const { return m_marginBox.logicalRight(style()->writingMode()); }
    294 
    295     virtual LayoutUnit marginBefore(const RenderStyle* overrideStyle = 0) const OVERRIDE FINAL { return m_marginBox.before((overrideStyle ? overrideStyle : style())->writingMode()); }
    296     virtual LayoutUnit marginAfter(const RenderStyle* overrideStyle = 0) const OVERRIDE FINAL { return m_marginBox.after((overrideStyle ? overrideStyle : style())->writingMode()); }
    297     virtual LayoutUnit marginStart(const RenderStyle* overrideStyle = 0) const OVERRIDE FINAL
    298     {
    299         const RenderStyle* styleToUse = overrideStyle ? overrideStyle : style();
    300         return m_marginBox.start(styleToUse->writingMode(), styleToUse->direction());
    301     }
    302     virtual LayoutUnit marginEnd(const RenderStyle* overrideStyle = 0) const OVERRIDE FINAL
    303     {
    304         const RenderStyle* styleToUse = overrideStyle ? overrideStyle : style();
    305         return m_marginBox.end(styleToUse->writingMode(), styleToUse->direction());
    306     }
    307     void setMarginBefore(LayoutUnit value, const RenderStyle* overrideStyle = 0) { m_marginBox.setBefore((overrideStyle ? overrideStyle : style())->writingMode(), value); }
    308     void setMarginAfter(LayoutUnit value, const RenderStyle* overrideStyle = 0) { m_marginBox.setAfter((overrideStyle ? overrideStyle : style())->writingMode(), value); }
    309     void setMarginStart(LayoutUnit value, const RenderStyle* overrideStyle = 0)
    310     {
    311         const RenderStyle* styleToUse = overrideStyle ? overrideStyle : style();
    312         m_marginBox.setStart(styleToUse->writingMode(), styleToUse->direction(), value);
    313     }
    314     void setMarginEnd(LayoutUnit value, const RenderStyle* overrideStyle = 0)
    315     {
    316         const RenderStyle* styleToUse = overrideStyle ? overrideStyle : style();
    317         m_marginBox.setEnd(styleToUse->writingMode(), styleToUse->direction(), value);
    318     }
    319 
    320     // The following functions are used to implement collapsing margins.
    321     // All objects know their maximal positive and negative margins.  The
    322     // formula for computing a collapsed margin is |maxPosMargin| - |maxNegmargin|.
    323     // For a non-collapsing box, such as a leaf element, this formula will simply return
    324     // the margin of the element.  Blocks override the maxMarginBefore and maxMarginAfter
    325     // methods.
    326     virtual bool isSelfCollapsingBlock() const { return false; }
    327     virtual LayoutUnit collapsedMarginBefore() const { return marginBefore(); }
    328     virtual LayoutUnit collapsedMarginAfter() const { return marginAfter(); }
    329 
    330     virtual void absoluteRects(Vector<IntRect>&, const LayoutPoint& accumulatedOffset) const OVERRIDE;
    331     virtual void absoluteQuads(Vector<FloatQuad>&, bool* wasFixed) const OVERRIDE;
    332 
    333     int reflectionOffset() const;
    334     // Given a rect in the object's coordinate space, returns the corresponding rect in the reflection.
    335     LayoutRect reflectedRect(const LayoutRect&) const;
    336 
    337     virtual void layout() OVERRIDE;
    338     virtual void paint(PaintInfo&, const LayoutPoint&) OVERRIDE;
    339     virtual bool nodeAtPoint(const HitTestRequest&, HitTestResult&, const HitTestLocation& locationInContainer, const LayoutPoint& accumulatedOffset, HitTestAction) OVERRIDE;
    340 
    341     virtual LayoutUnit minPreferredLogicalWidth() const OVERRIDE;
    342     virtual LayoutUnit maxPreferredLogicalWidth() const OVERRIDE;
    343 
    344     // FIXME: We should rename these back to overrideLogicalHeight/Width and have them store
    345     // the border-box height/width like the regular height/width accessors on RenderBox.
    346     // Right now, these are different than contentHeight/contentWidth because they still
    347     // include the scrollbar height/width.
    348     LayoutUnit overrideLogicalContentWidth() const;
    349     LayoutUnit overrideLogicalContentHeight() const;
    350     bool hasOverrideHeight() const;
    351     bool hasOverrideWidth() const;
    352     void setOverrideLogicalContentHeight(LayoutUnit);
    353     void setOverrideLogicalContentWidth(LayoutUnit);
    354     void clearOverrideSize();
    355     void clearOverrideLogicalContentHeight();
    356     void clearOverrideLogicalContentWidth();
    357 
    358     LayoutUnit overrideContainingBlockContentLogicalWidth() const;
    359     LayoutUnit overrideContainingBlockContentLogicalHeight() const;
    360     bool hasOverrideContainingBlockLogicalWidth() const;
    361     bool hasOverrideContainingBlockLogicalHeight() const;
    362     void setOverrideContainingBlockContentLogicalWidth(LayoutUnit);
    363     void setOverrideContainingBlockContentLogicalHeight(LayoutUnit);
    364     void clearContainingBlockOverrideSize();
    365     void clearOverrideContainingBlockContentLogicalHeight();
    366 
    367     virtual LayoutSize offsetFromContainer(const RenderObject*, const LayoutPoint&, bool* offsetDependsOnPoint = 0) const OVERRIDE;
    368 
    369     LayoutUnit adjustBorderBoxLogicalWidthForBoxSizing(LayoutUnit width) const;
    370     LayoutUnit adjustBorderBoxLogicalHeightForBoxSizing(LayoutUnit height) const;
    371     LayoutUnit adjustContentBoxLogicalWidthForBoxSizing(LayoutUnit width) const;
    372     LayoutUnit adjustContentBoxLogicalHeightForBoxSizing(LayoutUnit height) const;
    373 
    374     struct ComputedMarginValues {
    375         ComputedMarginValues() { }
    376 
    377         LayoutUnit m_before;
    378         LayoutUnit m_after;
    379         LayoutUnit m_start;
    380         LayoutUnit m_end;
    381     };
    382     struct LogicalExtentComputedValues {
    383         LogicalExtentComputedValues() { }
    384 
    385         LayoutUnit m_extent;
    386         LayoutUnit m_position;
    387         ComputedMarginValues m_margins;
    388     };
    389     // Resolve auto margins in the chosen direction of the containing block so that objects can be pushed to the start, middle or end
    390     // of the containing block.
    391     void computeMarginsForDirection(MarginDirection forDirection, const RenderBlock* containingBlock, LayoutUnit containerWidth, LayoutUnit childWidth, LayoutUnit& marginStart, LayoutUnit& marginEnd, Length marginStartLength, Length marginStartEnd) const;
    392 
    393     // Used to resolve margins in the containing block's block-flow direction.
    394     void computeAndSetBlockDirectionMargins(const RenderBlock* containingBlock);
    395 
    396     virtual LayoutUnit offsetFromLogicalTopOfFirstPage() const;
    397 
    398     void positionLineBox(InlineBox*);
    399     void moveWithEdgeOfInlineContainerIfNecessary(bool isHorizontal);
    400 
    401     virtual InlineBox* createInlineBox();
    402     void dirtyLineBoxes(bool fullLayout);
    403 
    404     // For inline replaced elements, this function returns the inline box that owns us.  Enables
    405     // the replaced RenderObject to quickly determine what line it is contained on and to easily
    406     // iterate over structures on the line.
    407     InlineBox* inlineBoxWrapper() const { return m_rareData ? m_rareData->m_inlineBoxWrapper : 0; }
    408     void setInlineBoxWrapper(InlineBox*);
    409     void deleteLineBoxWrapper();
    410 
    411     virtual LayoutRect clippedOverflowRectForPaintInvalidation(const RenderLayerModelObject* paintInvalidationContainer, const PaintInvalidationState* = 0) const OVERRIDE;
    412     virtual void mapRectToPaintInvalidationBacking(const RenderLayerModelObject* paintInvalidationContainer, LayoutRect&, const PaintInvalidationState*) const OVERRIDE;
    413     virtual void invalidatePaintForOverhangingFloats(bool paintAllDescendants);
    414 
    415     virtual LayoutUnit containingBlockLogicalWidthForContent() const OVERRIDE;
    416     LayoutUnit containingBlockLogicalHeightForContent(AvailableLogicalHeightType) const;
    417 
    418     LayoutUnit containingBlockAvailableLineWidth() const;
    419     LayoutUnit perpendicularContainingBlockLogicalHeight() const;
    420 
    421     virtual void updateLogicalWidth();
    422     virtual void updateLogicalHeight();
    423     virtual void computeLogicalHeight(LayoutUnit logicalHeight, LayoutUnit logicalTop, LogicalExtentComputedValues&) const;
    424 
    425     void computeLogicalWidth(LogicalExtentComputedValues&) const;
    426 
    427     bool stretchesToViewport() const
    428     {
    429         return document().inQuirksMode() && style()->logicalHeight().isAuto() && !isFloatingOrOutOfFlowPositioned() && (isDocumentElement() || isBody()) && !isInline();
    430     }
    431 
    432     virtual LayoutSize intrinsicSize() const { return LayoutSize(); }
    433     LayoutUnit intrinsicLogicalWidth() const { return style()->isHorizontalWritingMode() ? intrinsicSize().width() : intrinsicSize().height(); }
    434     LayoutUnit intrinsicLogicalHeight() const { return style()->isHorizontalWritingMode() ? intrinsicSize().height() : intrinsicSize().width(); }
    435     virtual LayoutUnit intrinsicContentLogicalHeight() const { return m_intrinsicContentLogicalHeight; }
    436 
    437     // Whether or not the element shrinks to its intrinsic width (rather than filling the width
    438     // of a containing block).  HTML4 buttons, <select>s, <input>s, legends, and floating/compact elements do this.
    439     bool sizesLogicalWidthToFitContent(const Length& logicalWidth) const;
    440 
    441     LayoutUnit shrinkLogicalWidthToAvoidFloats(LayoutUnit childMarginStart, LayoutUnit childMarginEnd, const RenderBlockFlow* cb) const;
    442 
    443     LayoutUnit computeLogicalWidthUsing(SizeType, const Length& logicalWidth, LayoutUnit availableLogicalWidth, const RenderBlock* containingBlock) const;
    444     LayoutUnit computeLogicalHeightUsing(const Length& height, LayoutUnit intrinsicContentHeight) const;
    445     LayoutUnit computeContentLogicalHeight(const Length& height, LayoutUnit intrinsicContentHeight) const;
    446     LayoutUnit computeContentAndScrollbarLogicalHeightUsing(const Length& height, LayoutUnit intrinsicContentHeight) const;
    447     LayoutUnit computeReplacedLogicalWidthUsing(const Length& width) const;
    448     LayoutUnit computeReplacedLogicalWidthRespectingMinMaxWidth(LayoutUnit logicalWidth, ShouldComputePreferred  = ComputeActual) const;
    449     LayoutUnit computeReplacedLogicalHeightUsing(const Length& height) const;
    450     LayoutUnit computeReplacedLogicalHeightRespectingMinMaxHeight(LayoutUnit logicalHeight) const;
    451 
    452     virtual LayoutUnit computeReplacedLogicalWidth(ShouldComputePreferred  = ComputeActual) const;
    453     virtual LayoutUnit computeReplacedLogicalHeight() const;
    454 
    455     static bool percentageLogicalHeightIsResolvableFromBlock(const RenderBlock* containingBlock, bool outOfFlowPositioned);
    456     LayoutUnit computePercentageLogicalHeight(const Length& height) const;
    457 
    458     // Block flows subclass availableWidth/Height to handle multi column layout (shrinking the width/height available to children when laying out.)
    459     virtual LayoutUnit availableLogicalWidth() const { return contentLogicalWidth(); }
    460     virtual LayoutUnit availableLogicalHeight(AvailableLogicalHeightType) const;
    461     LayoutUnit availableLogicalHeightUsing(const Length&, AvailableLogicalHeightType) const;
    462 
    463     // There are a few cases where we need to refer specifically to the available physical width and available physical height.
    464     // Relative positioning is one of those cases, since left/top offsets are physical.
    465     LayoutUnit availableWidth() const { return style()->isHorizontalWritingMode() ? availableLogicalWidth() : availableLogicalHeight(IncludeMarginBorderPadding); }
    466     LayoutUnit availableHeight() const { return style()->isHorizontalWritingMode() ? availableLogicalHeight(IncludeMarginBorderPadding) : availableLogicalWidth(); }
    467 
    468     virtual int verticalScrollbarWidth() const;
    469     int horizontalScrollbarHeight() const;
    470     int instrinsicScrollbarLogicalWidth() const;
    471     int scrollbarLogicalHeight() const { return style()->isHorizontalWritingMode() ? horizontalScrollbarHeight() : verticalScrollbarWidth(); }
    472     virtual bool scroll(ScrollDirection, ScrollGranularity, float delta = 1);
    473     bool canBeScrolledAndHasScrollableArea() const;
    474     virtual bool canBeProgramaticallyScrolled() const;
    475     virtual void autoscroll(const IntPoint&);
    476     bool autoscrollInProgress() const;
    477     bool canAutoscroll() const;
    478     IntSize calculateAutoscrollDirection(const IntPoint& windowPoint) const;
    479     static RenderBox* findAutoscrollable(RenderObject*);
    480     virtual void stopAutoscroll() { }
    481     virtual void panScroll(const IntPoint&);
    482 
    483     bool hasAutoVerticalScrollbar() const { return hasOverflowClip() && (style()->overflowY() == OAUTO || style()->overflowY() == OOVERLAY); }
    484     bool hasAutoHorizontalScrollbar() const { return hasOverflowClip() && (style()->overflowX() == OAUTO || style()->overflowX() == OOVERLAY); }
    485     bool scrollsOverflow() const { return scrollsOverflowX() || scrollsOverflowY(); }
    486 
    487     bool hasScrollableOverflowX() const { return scrollsOverflowX() && pixelSnappedScrollWidth() != pixelSnappedClientWidth(); }
    488     bool hasScrollableOverflowY() const { return scrollsOverflowY() && pixelSnappedScrollHeight() != pixelSnappedClientHeight(); }
    489     virtual bool scrollsOverflowX() const { return hasOverflowClip() && (style()->overflowX() == OSCROLL || hasAutoHorizontalScrollbar()); }
    490     virtual bool scrollsOverflowY() const { return hasOverflowClip() && (style()->overflowY() == OSCROLL || hasAutoVerticalScrollbar()); }
    491     bool usesCompositedScrolling() const;
    492 
    493     // Elements such as the <input> field override this to specify that they are scrollable
    494     // outside the context of the CSS overflow style
    495     virtual bool isIntristicallyScrollable(ScrollbarOrientation orientation) const { return false; }
    496 
    497     bool hasUnsplittableScrollingOverflow() const;
    498     bool isUnsplittableForPagination() const;
    499 
    500     virtual LayoutRect localCaretRect(InlineBox*, int caretOffset, LayoutUnit* extraWidthToEndOfLine = 0) OVERRIDE;
    501 
    502     virtual LayoutRect overflowClipRect(const LayoutPoint& location, OverlayScrollbarSizeRelevancy = IgnoreOverlayScrollbarSize);
    503     LayoutRect clipRect(const LayoutPoint& location);
    504     virtual bool hasControlClip() const { return false; }
    505     virtual LayoutRect controlClipRect(const LayoutPoint&) const { return LayoutRect(); }
    506     bool pushContentsClip(PaintInfo&, const LayoutPoint& accumulatedOffset, ContentsClipBehavior);
    507     void popContentsClip(PaintInfo&, PaintPhase originalPhase, const LayoutPoint& accumulatedOffset);
    508 
    509     virtual void paintObject(PaintInfo&, const LayoutPoint&) { ASSERT_NOT_REACHED(); }
    510     virtual void paintBoxDecorationBackground(PaintInfo&, const LayoutPoint&);
    511     virtual void paintMask(PaintInfo&, const LayoutPoint&);
    512     virtual void paintClippingMask(PaintInfo&, const LayoutPoint&);
    513     virtual void imageChanged(WrappedImagePtr, const IntRect* = 0) OVERRIDE;
    514 
    515     // Called when a positioned object moves but doesn't necessarily change size.  A simplified layout is attempted
    516     // that just updates the object's position. If the size does change, the object remains dirty.
    517     bool tryLayoutDoingPositionedMovementOnly()
    518     {
    519         LayoutUnit oldWidth = width();
    520         updateLogicalWidth();
    521         // If we shrink to fit our width may have changed, so we still need full layout.
    522         if (oldWidth != width())
    523             return false;
    524         updateLogicalHeight();
    525         return true;
    526     }
    527 
    528     virtual PositionWithAffinity positionForPoint(const LayoutPoint&) OVERRIDE;
    529 
    530     void removeFloatingOrPositionedChildFromBlockLists();
    531 
    532     RenderLayer* enclosingFloatPaintingLayer() const;
    533 
    534     virtual int firstLineBoxBaseline() const { return -1; }
    535     virtual int inlineBlockBaseline(LineDirectionMode) const { return -1; } // Returns -1 if we should skip this box when computing the baseline of an inline-block.
    536 
    537     bool shrinkToAvoidFloats() const;
    538     virtual bool avoidsFloats() const;
    539 
    540     virtual void markForPaginationRelayoutIfNeeded(SubtreeLayoutScope&);
    541 
    542     bool isWritingModeRoot() const { return !parent() || parent()->style()->writingMode() != style()->writingMode(); }
    543 
    544     bool isDeprecatedFlexItem() const { return !isInline() && !isFloatingOrOutOfFlowPositioned() && parent() && parent()->isDeprecatedFlexibleBox(); }
    545     bool isFlexItemIncludingDeprecated() const { return !isInline() && !isFloatingOrOutOfFlowPositioned() && parent() && parent()->isFlexibleBoxIncludingDeprecated(); }
    546 
    547     virtual LayoutUnit lineHeight(bool firstLine, LineDirectionMode, LinePositionMode = PositionOnContainingLine) const OVERRIDE;
    548     virtual int baselinePosition(FontBaseline, bool firstLine, LineDirectionMode, LinePositionMode = PositionOnContainingLine) const OVERRIDE;
    549 
    550     virtual LayoutUnit offsetLeft() const OVERRIDE;
    551     virtual LayoutUnit offsetTop() const OVERRIDE;
    552 
    553     LayoutPoint flipForWritingModeForChild(const RenderBox* child, const LayoutPoint&) const;
    554     LayoutUnit flipForWritingMode(LayoutUnit position) const; // The offset is in the block direction (y for horizontal writing modes, x for vertical writing modes).
    555     LayoutPoint flipForWritingMode(const LayoutPoint&) const;
    556     LayoutPoint flipForWritingModeIncludingColumns(const LayoutPoint&) const;
    557     LayoutSize flipForWritingMode(const LayoutSize&) const;
    558     void flipForWritingMode(LayoutRect&) const;
    559     FloatPoint flipForWritingMode(const FloatPoint&) const;
    560     void flipForWritingMode(FloatRect&) const;
    561     // These represent your location relative to your container as a physical offset.
    562     // In layout related methods you almost always want the logical location (e.g. x() and y()).
    563     LayoutPoint topLeftLocation() const;
    564     LayoutSize topLeftLocationOffset() const;
    565 
    566     LayoutRect logicalVisualOverflowRectForPropagation(RenderStyle*) const;
    567     LayoutRect visualOverflowRectForPropagation(RenderStyle*) const;
    568     LayoutRect logicalLayoutOverflowRectForPropagation(RenderStyle*) const;
    569     LayoutRect layoutOverflowRectForPropagation(RenderStyle*) const;
    570 
    571     bool hasRenderOverflow() const { return m_overflow; }
    572     bool hasVisualOverflow() const { return m_overflow && !borderBoxRect().contains(m_overflow->visualOverflowRect()); }
    573 
    574     virtual bool needsPreferredWidthsRecalculation() const;
    575     virtual void computeIntrinsicRatioInformation(FloatSize& /* intrinsicSize */, double& /* intrinsicRatio */) const { }
    576 
    577     IntSize scrolledContentOffset() const;
    578     void applyCachedClipAndScrollOffsetForPaintInvalidation(LayoutRect& paintRect) const;
    579 
    580     virtual bool hasRelativeLogicalHeight() const;
    581 
    582     bool hasHorizontalLayoutOverflow() const
    583     {
    584         if (!m_overflow)
    585             return false;
    586 
    587         LayoutRect layoutOverflowRect = m_overflow->layoutOverflowRect();
    588         LayoutRect noOverflowRect = this->noOverflowRect();
    589         return layoutOverflowRect.x() < noOverflowRect.x() || layoutOverflowRect.maxX() > noOverflowRect.maxX();
    590     }
    591 
    592     bool hasVerticalLayoutOverflow() const
    593     {
    594         if (!m_overflow)
    595             return false;
    596 
    597         LayoutRect layoutOverflowRect = m_overflow->layoutOverflowRect();
    598         LayoutRect noOverflowRect = this->noOverflowRect();
    599         return layoutOverflowRect.y() < noOverflowRect.y() || layoutOverflowRect.maxY() > noOverflowRect.maxY();
    600     }
    601 
    602     virtual RenderBox* createAnonymousBoxWithSameTypeAs(const RenderObject*) const
    603     {
    604         ASSERT_NOT_REACHED();
    605         return 0;
    606     }
    607 
    608     bool hasSameDirectionAs(const RenderBox* object) const { return style()->direction() == object->style()->direction(); }
    609 
    610     ShapeOutsideInfo* shapeOutsideInfo() const
    611     {
    612         return ShapeOutsideInfo::isEnabledFor(*this) ? ShapeOutsideInfo::info(*this) : 0;
    613     }
    614 
    615     void markShapeOutsideDependentsForLayout()
    616     {
    617         if (isFloating())
    618             removeFloatingOrPositionedChildFromBlockLists();
    619     }
    620 
    621     bool backgroundHasOpaqueTopLayer() const;
    622 
    623     void updateIntrinsicContentLogicalHeight(LayoutUnit intrinsicContentLogicalHeight) const { m_intrinsicContentLogicalHeight = intrinsicContentLogicalHeight; }
    624 protected:
    625     virtual void willBeDestroyed() OVERRIDE;
    626 
    627 
    628     virtual void styleWillChange(StyleDifference, const RenderStyle& newStyle) OVERRIDE;
    629     virtual void styleDidChange(StyleDifference, const RenderStyle* oldStyle) OVERRIDE;
    630     virtual void updateFromStyle() OVERRIDE;
    631 
    632     // Returns false if it could not cheaply compute the extent (e.g. fixed background), in which case the returned rect may be incorrect.
    633     // FIXME: make this a const method once the RenderBox reference in BoxPainter is const.
    634     bool getBackgroundPaintedExtent(LayoutRect&);
    635     virtual bool foregroundIsKnownToBeOpaqueInRect(const LayoutRect& localRect, unsigned maxDepthToTest) const;
    636     virtual bool computeBackgroundIsKnownToBeObscured() OVERRIDE;
    637 
    638     void computePositionedLogicalWidth(LogicalExtentComputedValues&) const;
    639 
    640     LayoutUnit computeIntrinsicLogicalWidthUsing(const Length& logicalWidthLength, LayoutUnit availableLogicalWidth, LayoutUnit borderAndPadding) const;
    641     LayoutUnit computeIntrinsicLogicalContentHeightUsing(const Length& logicalHeightLength, LayoutUnit intrinsicContentHeight, LayoutUnit borderAndPadding) const;
    642 
    643     virtual bool shouldComputeSizeAsReplaced() const { return isReplaced() && !isInlineBlockOrInlineTable(); }
    644 
    645     virtual void mapLocalToContainer(const RenderLayerModelObject* paintInvalidationContainer, TransformState&, MapCoordinatesFlags = ApplyContainerFlip, bool* wasFixed = 0, const PaintInvalidationState* = 0) const OVERRIDE;
    646     virtual void mapAbsoluteToLocalPoint(MapCoordinatesFlags, TransformState&) const OVERRIDE;
    647 
    648     RenderObject* splitAnonymousBoxesAroundChild(RenderObject* beforeChild);
    649 
    650     virtual void addLayerHitTestRects(LayerHitTestRects&, const RenderLayer* currentCompositedLayer, const LayoutPoint& layerOffset, const LayoutRect& containerRect) const OVERRIDE;
    651     virtual void computeSelfHitTestRects(Vector<LayoutRect>&, const LayoutPoint& layerOffset) const OVERRIDE;
    652 
    653     virtual InvalidationReason getPaintInvalidationReason(const RenderLayerModelObject& paintInvalidationContainer,
    654         const LayoutRect& oldBounds, const LayoutPoint& oldPositionFromPaintInvalidationContainer,
    655         const LayoutRect& newBounds, const LayoutPoint& newPositionFromPaintInvalidationContainer) OVERRIDE;
    656     virtual void incrementallyInvalidatePaint(const RenderLayerModelObject& paintInvalidationContainer, const LayoutRect& oldBounds, const LayoutRect& newBounds, const LayoutPoint& positionFromPaintInvalidationContainer) OVERRIDE;
    657 
    658     virtual void clearPaintInvalidationState(const PaintInvalidationState&) OVERRIDE;
    659 #if ENABLE(ASSERT)
    660     virtual bool paintInvalidationStateIsDirty() const OVERRIDE;
    661 #endif
    662 
    663 private:
    664     void invalidatePaintRectClippedByOldAndNewBounds(const RenderLayerModelObject& paintInvalidationContainer, const LayoutRect&, const LayoutRect& oldBounds, const LayoutRect& newBounds);
    665 
    666     void updateShapeOutsideInfoAfterStyleChange(const RenderStyle&, const RenderStyle* oldStyle);
    667     void updateGridPositionAfterStyleChange(const RenderStyle*);
    668 
    669     bool autoWidthShouldFitContent() const;
    670     void shrinkToFitWidth(const LayoutUnit availableSpace, const LayoutUnit logicalLeftValue, const LayoutUnit bordersPlusPadding, LogicalExtentComputedValues&) const;
    671 
    672     // Returns true if we queued up a paint invalidation.
    673     bool paintInvalidationLayerRectsForImage(WrappedImagePtr, const FillLayer&, bool drawingBackground);
    674 
    675     bool skipContainingBlockForPercentHeightCalculation(const RenderBox* containingBlock) const;
    676 
    677     LayoutUnit containingBlockLogicalWidthForPositioned(const RenderBoxModelObject* containingBlock, bool checkForPerpendicularWritingMode = true) const;
    678     LayoutUnit containingBlockLogicalHeightForPositioned(const RenderBoxModelObject* containingBlock, bool checkForPerpendicularWritingMode = true) const;
    679 
    680     void computePositionedLogicalHeight(LogicalExtentComputedValues&) const;
    681     void computePositionedLogicalWidthUsing(Length logicalWidth, const RenderBoxModelObject* containerBlock, TextDirection containerDirection,
    682                                             LayoutUnit containerLogicalWidth, LayoutUnit bordersPlusPadding,
    683                                             const Length& logicalLeft, const Length& logicalRight, const Length& marginLogicalLeft,
    684                                             const Length& marginLogicalRight, LogicalExtentComputedValues&) const;
    685     void computePositionedLogicalHeightUsing(Length logicalHeightLength, const RenderBoxModelObject* containerBlock,
    686                                              LayoutUnit containerLogicalHeight, LayoutUnit bordersPlusPadding, LayoutUnit logicalHeight,
    687                                              const Length& logicalTop, const Length& logicalBottom, const Length& marginLogicalTop,
    688                                              const Length& marginLogicalBottom, LogicalExtentComputedValues&) const;
    689 
    690     void computePositionedLogicalHeightReplaced(LogicalExtentComputedValues&) const;
    691     void computePositionedLogicalWidthReplaced(LogicalExtentComputedValues&) const;
    692 
    693     LayoutUnit fillAvailableMeasure(LayoutUnit availableLogicalWidth) const;
    694     LayoutUnit fillAvailableMeasure(LayoutUnit availableLogicalWidth, LayoutUnit& marginStart, LayoutUnit& marginEnd) const;
    695 
    696     virtual void computeIntrinsicLogicalWidths(LayoutUnit& minLogicalWidth, LayoutUnit& maxLogicalWidth) const;
    697 
    698     // This function calculates the minimum and maximum preferred widths for an object.
    699     // These values are used in shrink-to-fit layout systems.
    700     // These include tables, positioned objects, floats and flexible boxes.
    701     virtual void computePreferredLogicalWidths() { clearPreferredLogicalWidthsDirty(); }
    702 
    703     RenderBoxRareData& ensureRareData()
    704     {
    705         if (!m_rareData)
    706             m_rareData = adoptPtr(new RenderBoxRareData());
    707         return *m_rareData.get();
    708     }
    709 
    710     void savePreviousBorderBoxSizeIfNeeded();
    711     LayoutSize computePreviousBorderBoxSize(const LayoutSize& previousBoundsSize) const;
    712 
    713     bool logicalHeightComputesAsNone(SizeType) const;
    714 
    715     virtual InvalidationReason invalidatePaintIfNeeded(const PaintInvalidationState&, const RenderLayerModelObject& newPaintInvalidationContainer) OVERRIDE FINAL;
    716 
    717     bool isBox() const WTF_DELETED_FUNCTION; // This will catch anyone doing an unnecessary check.
    718 
    719     // The width/height of the contents + borders + padding.  The x/y location is relative to our container (which is not always our parent).
    720     LayoutRect m_frameRect;
    721 
    722     // Our intrinsic height, used for min-height: min-content etc. Maintained by
    723     // updateLogicalHeight. This is logicalHeight() before it is clamped to
    724     // min/max.
    725     mutable LayoutUnit m_intrinsicContentLogicalHeight;
    726 
    727     void inflatePaintInvalidationRectForReflectionAndFilter(LayoutRect&) const;
    728 
    729 protected:
    730     LayoutBoxExtent m_marginBox;
    731 
    732     // The preferred logical width of the element if it were to break its lines at every possible opportunity.
    733     LayoutUnit m_minPreferredLogicalWidth;
    734 
    735     // The preferred logical width of the element if it never breaks any lines at all.
    736     LayoutUnit m_maxPreferredLogicalWidth;
    737 
    738     // Our overflow information.
    739     OwnPtr<RenderOverflow> m_overflow;
    740 
    741 private:
    742     OwnPtr<RenderBoxRareData> m_rareData;
    743 };
    744 
    745 DEFINE_RENDER_OBJECT_TYPE_CASTS(RenderBox, isBox());
    746 
    747 inline RenderBox* RenderBox::previousSiblingBox() const
    748 {
    749     return toRenderBox(previousSibling());
    750 }
    751 
    752 inline RenderBox* RenderBox::nextSiblingBox() const
    753 {
    754     return toRenderBox(nextSibling());
    755 }
    756 
    757 inline RenderBox* RenderBox::parentBox() const
    758 {
    759     return toRenderBox(parent());
    760 }
    761 
    762 inline RenderBox* RenderBox::firstChildBox() const
    763 {
    764     return toRenderBox(slowFirstChild());
    765 }
    766 
    767 inline RenderBox* RenderBox::lastChildBox() const
    768 {
    769     return toRenderBox(slowLastChild());
    770 }
    771 
    772 inline void RenderBox::setInlineBoxWrapper(InlineBox* boxWrapper)
    773 {
    774     if (boxWrapper) {
    775         ASSERT(!inlineBoxWrapper());
    776         // m_inlineBoxWrapper should already be 0. Deleting it is a safeguard against security issues.
    777         // Otherwise, there will two line box wrappers keeping the reference to this renderer, and
    778         // only one will be notified when the renderer is getting destroyed. The second line box wrapper
    779         // will keep a stale reference.
    780         if (UNLIKELY(inlineBoxWrapper() != 0))
    781             deleteLineBoxWrapper();
    782     }
    783 
    784     ensureRareData().m_inlineBoxWrapper = boxWrapper;
    785 }
    786 
    787 } // namespace blink
    788 
    789 #endif // RenderBox_h
    790