root/Source/core/rendering/RenderBoxModelObject.cpp

DEFINITIONS

1. setSelectionState
2. contentChanged
3. hasAcceleratedCompositing
4. chooseInterpolationQuality
5. willBeDestroyed
6. updateFromStyle
7. accumulateInFlowPositionOffsets
8. hasAutoHeightOrContainingBlockWithAutoHeight
9. relativePositionOffset
10. adjustedPositionRelativeToOffsetParent
11. computeStickyPositionConstraints
12. stickyPositionOffset
13. offsetForInFlowPosition
14. offsetLeft
15. offsetTop
16. pixelSnappedOffsetWidth
17. pixelSnappedOffsetHeight
18. computedCSSPadding
19. getBackgroundRoundedRect
20. clipRoundedInnerRect
21. shrinkRectByOnePixel
22. borderInnerRectAdjustedForBleedAvoidance
23. backgroundRoundedRectAdjustedForBleedAvoidance
24. applyBoxShadowForBackground
25. paintFillLayerExtended
26. resolveWidthForRatio
27. resolveHeightForRatio
28. resolveAgainstIntrinsicWidthOrHeightAndRatio
29. resolveAgainstIntrinsicRatio
30. calculateImageIntrinsicDimensions
31. applySubPixelHeuristicForTileSize
32. calculateFillTileSize
33. setNoRepeatX
34. setNoRepeatY
35. useFixedAttachment
36. clip
37. relativePhase
38. fixedBackgroundPaintsInLocalCoordinates
39. getSpace
40. calculateBackgroundImageGeometry
41. computeBorderImageSide
42. paintNinePieceImage
43. isPresent
44. isPresent
45. hasVisibleColorAndStyle
46. shouldRender
47. presentButInvisible
48. obscuresBackgroundEdge
49. obscuresBackground
50. usedWidth
51. getDoubleBorderStripeWidths
52. allCornersClippedOut
53. borderWillArcInnerEdge
54. edgeFlagForSide
55. includesEdge
56. includesAdjacentEdges
57. edgesShareColor
58. styleRequiresClipPolygon
59. borderStyleFillsBorderArea
60. borderStyleHasInnerDetail
61. borderStyleIsDottedOrDashed
62. borderStyleHasUnmatchedColorsAtCorner
63. colorsMatchAtCorner
64. colorNeedsAntiAliasAtCorner
65. willBeOverdrawn
66. borderStylesRequireMitre
67. joinRequiresMitre
68. paintOneBorderSide
69. calculateSideRect
70. paintBorderSides
71. paintTranslucentBorderSides
72. paintBorder
73. drawBoxSideFromPath
74. clipBorderSidePolygon
75. calculateSideRectIncludingInner
76. calculateAdjustedInnerBorder
77. clipBorderSideForComplexInnerPath
78. getBorderEdgeInfo
79. borderObscuresBackgroundEdge
80. borderObscuresBackground
81. boxShadowShouldBeAppliedToBackground
82. paintBoxShadow
83. containingBlockLogicalWidthForContent
84. continuation
85. setContinuation
86. computeLayerHitTestRects
87. firstLetterRemainingText
88. setFirstLetterRemainingText
89. localCaretRectForEmptyElement
90. shouldAntialiasLines
91. mapAbsoluteToLocalPoint
92. pushMappingToContainer
93. moveChildTo
94. moveChildrenTo

/*
 * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
 *           (C) 1999 Antti Koivisto (koivisto@kde.org)
 *           (C) 2005 Allan Sandfeld Jensen (kde@carewolf.com)
 *           (C) 2005, 2006 Samuel Weinig (sam.weinig@gmail.com)
 * Copyright (C) 2005, 2006, 2007, 2008, 2009 Apple Inc. All rights reserved.
 * Copyright (C) 2010 Google Inc. All rights reserved.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public License
 * along with this library; see the file COPYING.LIB.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA 02110-1301, USA.
 *
 */

#include "config.h"
#include "core/rendering/RenderBoxModelObject.h"

#include "HTMLNames.h"
#include "core/frame/Settings.h"
#include "core/html/HTMLFrameOwnerElement.h"
#include "core/page/scrolling/ScrollingConstraints.h"
#include "core/rendering/ImageQualityController.h"
#include "core/rendering/RenderBlock.h"
#include "core/rendering/RenderFlowThread.h"
#include "core/rendering/RenderGeometryMap.h"
#include "core/rendering/RenderInline.h"
#include "core/rendering/RenderLayer.h"
#include "core/rendering/RenderRegion.h"
#include "core/rendering/RenderView.h"
#include "core/rendering/compositing/CompositedLayerMapping.h"
#include "core/rendering/compositing/RenderLayerCompositor.h"
#include "core/rendering/style/ShadowList.h"
#include "platform/geometry/TransformState.h"
#include "platform/graphics/DrawLooperBuilder.h"
#include "platform/graphics/GraphicsContextStateSaver.h"
#include "platform/graphics/Path.h"
#include "wtf/CurrentTime.h"

using namespace std;

namespace WebCore {

using namespace HTMLNames;

// The HashMap for storing continuation pointers.
// An inline can be split with blocks occuring in between the inline content.
// When this occurs we need a pointer to the next object. We can basically be
// split into a sequence of inlines and blocks. The continuation will either be
// an anonymous block (that houses other blocks) or it will be an inline flow.
// <b><i><p>Hello</p></i></b>. In this example the <i> will have a block as
// its continuation but the <b> will just have an inline as its continuation.
typedef HashMap<const RenderBoxModelObject*, RenderBoxModelObject*> ContinuationMap;
static ContinuationMap* continuationMap = 0;

// This HashMap is similar to the continuation map, but connects first-letter
// renderers to their remaining text fragments.
typedef HashMap<const RenderBoxModelObject*, RenderTextFragment*> FirstLetterRemainingTextMap;
static FirstLetterRemainingTextMap* firstLetterRemainingTextMap = 0;

void RenderBoxModelObject::setSelectionState(SelectionState state)
{
    if (state == SelectionInside && selectionState() != SelectionNone)
        return;

    if ((state == SelectionStart && selectionState() == SelectionEnd)
        || (state == SelectionEnd && selectionState() == SelectionStart))
        RenderObject::setSelectionState(SelectionBoth);
    else
        RenderObject::setSelectionState(state);

    // FIXME: We should consider whether it is OK propagating to ancestor RenderInlines.
    // This is a workaround for http://webkit.org/b/32123
    // The containing block can be null in case of an orphaned tree.
    RenderBlock* containingBlock = this->containingBlock();
    if (containingBlock && !containingBlock->isRenderView())
        containingBlock->setSelectionState(state);
}

void RenderBoxModelObject::contentChanged(ContentChangeType changeType)
{
    if (!hasLayer())
        return;

    layer()->contentChanged(changeType);
}

bool RenderBoxModelObject::hasAcceleratedCompositing() const
{
    return view()->compositor()->hasAcceleratedCompositing();
}

InterpolationQuality RenderBoxModelObject::chooseInterpolationQuality(GraphicsContext* context, Image* image, const void* layer, const LayoutSize& size)
{
    return ImageQualityController::imageQualityController()->chooseInterpolationQuality(context, this, image, layer, size);
}

RenderBoxModelObject::RenderBoxModelObject(ContainerNode* node)
    : RenderLayerModelObject(node)
{
}

RenderBoxModelObject::~RenderBoxModelObject()
{
    ImageQualityController::remove(this);
}

void RenderBoxModelObject::willBeDestroyed()
{
    // A continuation of this RenderObject should be destroyed at subclasses.
    ASSERT(!continuation());

    // If this is a first-letter object with a remaining text fragment then the
    // entry needs to be cleared from the map.
    if (firstLetterRemainingText())
        setFirstLetterRemainingText(0);

    RenderLayerModelObject::willBeDestroyed();
}

void RenderBoxModelObject::updateFromStyle()
{
    RenderLayerModelObject::updateFromStyle();

    RenderStyle* styleToUse = style();
    setHasBoxDecorations(hasBackground() || styleToUse->hasBorder() || styleToUse->hasAppearance() || styleToUse->boxShadow());
    setInline(styleToUse->isDisplayInlineType());
    setPositionState(styleToUse->position());
    setHorizontalWritingMode(styleToUse->isHorizontalWritingMode());
}

static LayoutSize accumulateInFlowPositionOffsets(const RenderObject* child)
{
    if (!child->isAnonymousBlock() || !child->isInFlowPositioned())
        return LayoutSize();
    LayoutSize offset;
    RenderObject* p = toRenderBlock(child)->inlineElementContinuation();
    while (p && p->isRenderInline()) {
        if (p->isInFlowPositioned()) {
            RenderInline* renderInline = toRenderInline(p);
            offset += renderInline->offsetForInFlowPosition();
        }
        p = p->parent();
    }
    return offset;
}

bool RenderBoxModelObject::hasAutoHeightOrContainingBlockWithAutoHeight() const
{
    Length logicalHeightLength = style()->logicalHeight();
    if (logicalHeightLength.isAuto())
        return true;

    // For percentage heights: The percentage is calculated with respect to the height of the generated box's
    // containing block. If the height of the containing block is not specified explicitly (i.e., it depends
    // on content height), and this element is not absolutely positioned, the value computes to 'auto'.
    if (!logicalHeightLength.isPercent() || isOutOfFlowPositioned() || document().inQuirksMode())
        return false;

    // Anonymous block boxes are ignored when resolving percentage values that would refer to it:
    // the closest non-anonymous ancestor box is used instead.
    RenderBlock* cb = containingBlock();
    while (cb->isAnonymous())
        cb = cb->containingBlock();

    // Matching RenderBox::percentageLogicalHeightIsResolvableFromBlock() by
    // ignoring table cell's attribute value, where it says that table cells violate
    // what the CSS spec says to do with heights. Basically we
    // don't care if the cell specified a height or not.
    if (cb->isTableCell())
        return false;

    if (!cb->style()->logicalHeight().isAuto() || (!cb->style()->logicalTop().isAuto() && !cb->style()->logicalBottom().isAuto()))
        return false;

    return true;
}

LayoutSize RenderBoxModelObject::relativePositionOffset() const
{
    LayoutSize offset = accumulateInFlowPositionOffsets(this);

    RenderBlock* containingBlock = this->containingBlock();

    // Objects that shrink to avoid floats normally use available line width when computing containing block width.  However
    // in the case of relative positioning using percentages, we can't do this.  The offset should always be resolved using the
    // available width of the containing block.  Therefore we don't use containingBlockLogicalWidthForContent() here, but instead explicitly
    // call availableWidth on our containing block.
    if (!style()->left().isAuto()) {
        if (!style()->right().isAuto() && !containingBlock->style()->isLeftToRightDirection())
            offset.setWidth(-valueForLength(style()->right(), containingBlock->availableWidth()));
        else
            offset.expand(valueForLength(style()->left(), containingBlock->availableWidth()), 0);
    } else if (!style()->right().isAuto()) {
        offset.expand(-valueForLength(style()->right(), containingBlock->availableWidth()), 0);
    }

    // If the containing block of a relatively positioned element does not
    // specify a height, a percentage top or bottom offset should be resolved as
    // auto. An exception to this is if the containing block has the WinIE quirk
    // where <html> and <body> assume the size of the viewport. In this case,
    // calculate the percent offset based on this height.
    // See <https://bugs.webkit.org/show_bug.cgi?id=26396>.
    if (!style()->top().isAuto()
        && (!containingBlock->hasAutoHeightOrContainingBlockWithAutoHeight()
            || !style()->top().isPercent()
            || containingBlock->stretchesToViewport()))
        offset.expand(0, valueForLength(style()->top(), containingBlock->availableHeight()));

    else if (!style()->bottom().isAuto()
        && (!containingBlock->hasAutoHeightOrContainingBlockWithAutoHeight()
            || !style()->bottom().isPercent()
            || containingBlock->stretchesToViewport()))
        offset.expand(0, -valueForLength(style()->bottom(), containingBlock->availableHeight()));

    return offset;
}

LayoutPoint RenderBoxModelObject::adjustedPositionRelativeToOffsetParent(const LayoutPoint& startPoint) const
{
    // If the element is the HTML body element or doesn't have a parent
    // return 0 and stop this algorithm.
    if (isBody() || !parent())
        return LayoutPoint();

    LayoutPoint referencePoint = startPoint;
    referencePoint.move(parent()->offsetForColumns(referencePoint));

    // If the offsetParent of the element is null, or is the HTML body element,
    // return the distance between the canvas origin and the left border edge
    // of the element and stop this algorithm.
    Element* element = offsetParent();
    if (!element)
        return referencePoint;

    if (const RenderBoxModelObject* offsetParent = element->renderBoxModelObject()) {
        if (offsetParent->isBox() && !offsetParent->isBody())
            referencePoint.move(-toRenderBox(offsetParent)->borderLeft(), -toRenderBox(offsetParent)->borderTop());
        if (!isOutOfFlowPositioned() || flowThreadContainingBlock()) {
            if (isRelPositioned())
                referencePoint.move(relativePositionOffset());
            else if (isStickyPositioned())
                referencePoint.move(stickyPositionOffset());

            RenderObject* current;
            for (current = parent(); current != offsetParent && current->parent(); current = current->parent()) {
                // FIXME: What are we supposed to do inside SVG content?
                if (!isOutOfFlowPositioned()) {
                    if (current->isBox() && !current->isTableRow())
                        referencePoint.moveBy(toRenderBox(current)->topLeftLocation());
                    referencePoint.move(current->parent()->offsetForColumns(referencePoint));
                }
            }

            if (offsetParent->isBox() && offsetParent->isBody() && !offsetParent->isPositioned())
                referencePoint.moveBy(toRenderBox(offsetParent)->topLeftLocation());
        }
    }

    return referencePoint;
}

void RenderBoxModelObject::computeStickyPositionConstraints(StickyPositionViewportConstraints& constraints, const FloatRect& constrainingRect) const
{
    RenderBlock* containingBlock = this->containingBlock();

    LayoutRect containerContentRect = containingBlock->contentBoxRect();
    LayoutUnit maxWidth = containingBlock->availableLogicalWidth();

    // Sticky positioned element ignore any override logical width on the containing block (as they don't call
    // containingBlockLogicalWidthForContent). It's unclear whether this is totally fine.
    LayoutBoxExtent minMargin(minimumValueForLength(style()->marginTop(), maxWidth),
        minimumValueForLength(style()->marginRight(), maxWidth),
        minimumValueForLength(style()->marginBottom(), maxWidth),
        minimumValueForLength(style()->marginLeft(), maxWidth));

    // Compute the container-relative area within which the sticky element is allowed to move.
    containerContentRect.contract(minMargin);
    // Map to the view to avoid including page scale factor.
    constraints.setAbsoluteContainingBlockRect(containingBlock->localToContainerQuad(FloatRect(containerContentRect), view()).boundingBox());

    LayoutRect stickyBoxRect = frameRectForStickyPositioning();
    LayoutRect flippedStickyBoxRect = stickyBoxRect;
    containingBlock->flipForWritingMode(flippedStickyBoxRect);
    LayoutPoint stickyLocation = flippedStickyBoxRect.location();

    // FIXME: sucks to call localToAbsolute again, but we can't just offset from the previously computed rect if there are transforms.
    // Map to the view to avoid including page scale factor.
    FloatRect absContainerFrame = containingBlock->localToContainerQuad(FloatRect(FloatPoint(), containingBlock->size()), view()).boundingBox();

    if (containingBlock->hasOverflowClip()) {
        IntSize scrollOffset = containingBlock->layer()->scrollableArea()->adjustedScrollOffset();
        stickyLocation -= scrollOffset;
    }

    // We can't call localToAbsolute on |this| because that will recur. FIXME: For now, assume that |this| is not transformed.
    FloatRect absoluteStickyBoxRect(absContainerFrame.location() + stickyLocation, flippedStickyBoxRect.size());
    constraints.setAbsoluteStickyBoxRect(absoluteStickyBoxRect);

    if (!style()->left().isAuto()) {
        constraints.setLeftOffset(floatValueForLength(style()->left(), constrainingRect.width()));
        constraints.addAnchorEdge(ViewportConstraints::AnchorEdgeLeft);
    }

    if (!style()->right().isAuto()) {
        constraints.setRightOffset(floatValueForLength(style()->right(), constrainingRect.width()));
        constraints.addAnchorEdge(ViewportConstraints::AnchorEdgeRight);
    }

    if (!style()->top().isAuto()) {
        constraints.setTopOffset(floatValueForLength(style()->top(), constrainingRect.height()));
        constraints.addAnchorEdge(ViewportConstraints::AnchorEdgeTop);
    }

    if (!style()->bottom().isAuto()) {
        constraints.setBottomOffset(floatValueForLength(style()->bottom(), constrainingRect.height() ));
        constraints.addAnchorEdge(ViewportConstraints::AnchorEdgeBottom);
    }
}

LayoutSize RenderBoxModelObject::stickyPositionOffset() const
{
    FloatRect constrainingRect;

    ASSERT(hasLayer());
    RenderLayer* enclosingClippingLayer = layer()->enclosingOverflowClipLayer(ExcludeSelf);
    if (enclosingClippingLayer) {
        RenderBox* enclosingClippingBox = toRenderBox(enclosingClippingLayer->renderer());
        LayoutRect clipRect = enclosingClippingBox->overflowClipRect(LayoutPoint());
        clipRect.move(enclosingClippingBox->paddingLeft(), enclosingClippingBox->paddingTop());
        clipRect.contract(LayoutSize(enclosingClippingBox->paddingLeft() + enclosingClippingBox->paddingRight(),
            enclosingClippingBox->paddingTop() + enclosingClippingBox->paddingBottom()));
        constrainingRect = enclosingClippingBox->localToContainerQuad(FloatRect(clipRect), view()).boundingBox();
    } else {
        LayoutRect viewportRect = view()->frameView()->viewportConstrainedVisibleContentRect();
        constrainingRect = viewportRect;
    }

    StickyPositionViewportConstraints constraints;
    computeStickyPositionConstraints(constraints, constrainingRect);

    // The sticky offset is physical, so we can just return the delta computed in absolute coords (though it may be wrong with transforms).
    return LayoutSize(constraints.computeStickyOffset(constrainingRect));
}

LayoutSize RenderBoxModelObject::offsetForInFlowPosition() const
{
    if (isRelPositioned())
        return relativePositionOffset();

    if (isStickyPositioned())
        return stickyPositionOffset();

    return LayoutSize();
}

LayoutUnit RenderBoxModelObject::offsetLeft() const
{
    // Note that RenderInline and RenderBox override this to pass a different
    // startPoint to adjustedPositionRelativeToOffsetParent.
    return adjustedPositionRelativeToOffsetParent(LayoutPoint()).x();
}

LayoutUnit RenderBoxModelObject::offsetTop() const
{
    // Note that RenderInline and RenderBox override this to pass a different
    // startPoint to adjustedPositionRelativeToOffsetParent.
    return adjustedPositionRelativeToOffsetParent(LayoutPoint()).y();
}

int RenderBoxModelObject::pixelSnappedOffsetWidth() const
{
    return snapSizeToPixel(offsetWidth(), offsetLeft());
}

int RenderBoxModelObject::pixelSnappedOffsetHeight() const
{
    return snapSizeToPixel(offsetHeight(), offsetTop());
}

LayoutUnit RenderBoxModelObject::computedCSSPadding(Length padding) const
{
    LayoutUnit w = 0;
    if (padding.isPercent())
        w = containingBlockLogicalWidthForContent();
    return minimumValueForLength(padding, w);
}

RoundedRect RenderBoxModelObject::getBackgroundRoundedRect(const LayoutRect& borderRect, InlineFlowBox* box, LayoutUnit inlineBoxWidth, LayoutUnit inlineBoxHeight,
    bool includeLogicalLeftEdge, bool includeLogicalRightEdge) const
{
    RoundedRect border = style()->getRoundedBorderFor(borderRect, includeLogicalLeftEdge, includeLogicalRightEdge);
    if (box && (box->nextLineBox() || box->prevLineBox())) {
        RoundedRect segmentBorder = style()->getRoundedBorderFor(LayoutRect(0, 0, inlineBoxWidth, inlineBoxHeight), includeLogicalLeftEdge, includeLogicalRightEdge);
        border.setRadii(segmentBorder.radii());
    }

    return border;
}

void RenderBoxModelObject::clipRoundedInnerRect(GraphicsContext * context, const LayoutRect& rect, const RoundedRect& clipRect)
{
    if (clipRect.isRenderable())
        context->clipRoundedRect(clipRect);
    else {
        // We create a rounded rect for each of the corners and clip it, while making sure we clip opposing corners together.
        if (!clipRect.radii().topLeft().isEmpty() || !clipRect.radii().bottomRight().isEmpty()) {
            IntRect topCorner(clipRect.rect().x(), clipRect.rect().y(), rect.maxX() - clipRect.rect().x(), rect.maxY() - clipRect.rect().y());
            RoundedRect::Radii topCornerRadii;
            topCornerRadii.setTopLeft(clipRect.radii().topLeft());
            context->clipRoundedRect(RoundedRect(topCorner, topCornerRadii));

            IntRect bottomCorner(rect.x(), rect.y(), clipRect.rect().maxX() - rect.x(), clipRect.rect().maxY() - rect.y());
            RoundedRect::Radii bottomCornerRadii;
            bottomCornerRadii.setBottomRight(clipRect.radii().bottomRight());
            context->clipRoundedRect(RoundedRect(bottomCorner, bottomCornerRadii));
        }

        if (!clipRect.radii().topRight().isEmpty() || !clipRect.radii().bottomLeft().isEmpty()) {
            IntRect topCorner(rect.x(), clipRect.rect().y(), clipRect.rect().maxX() - rect.x(), rect.maxY() - clipRect.rect().y());
            RoundedRect::Radii topCornerRadii;
            topCornerRadii.setTopRight(clipRect.radii().topRight());
            context->clipRoundedRect(RoundedRect(topCorner, topCornerRadii));

            IntRect bottomCorner(clipRect.rect().x(), rect.y(), rect.maxX() - clipRect.rect().x(), clipRect.rect().maxY() - rect.y());
            RoundedRect::Radii bottomCornerRadii;
            bottomCornerRadii.setBottomLeft(clipRect.radii().bottomLeft());
            context->clipRoundedRect(RoundedRect(bottomCorner, bottomCornerRadii));
        }
    }
}

static LayoutRect shrinkRectByOnePixel(GraphicsContext* context, const LayoutRect& rect)
{
    LayoutRect shrunkRect = rect;
    AffineTransform transform = context->getCTM();
    shrunkRect.inflateX(-static_cast<LayoutUnit>(ceil(1 / transform.xScale())));
    shrunkRect.inflateY(-static_cast<LayoutUnit>(ceil(1 / transform.yScale())));
    return shrunkRect;
}

LayoutRect RenderBoxModelObject::borderInnerRectAdjustedForBleedAvoidance(GraphicsContext* context, const LayoutRect& rect, BackgroundBleedAvoidance bleedAvoidance) const
{
    // We shrink the rectangle by one pixel on each side to make it fully overlap the anti-aliased background border
    return (bleedAvoidance == BackgroundBleedBackgroundOverBorder) ? shrinkRectByOnePixel(context, rect) : rect;
}

RoundedRect RenderBoxModelObject::backgroundRoundedRectAdjustedForBleedAvoidance(GraphicsContext* context, const LayoutRect& borderRect, BackgroundBleedAvoidance bleedAvoidance, InlineFlowBox* box, const LayoutSize& boxSize, bool includeLogicalLeftEdge, bool includeLogicalRightEdge) const
{
    if (bleedAvoidance == BackgroundBleedShrinkBackground) {
        // We shrink the rectangle by one pixel on each side because the bleed is one pixel maximum.
        return getBackgroundRoundedRect(shrinkRectByOnePixel(context, borderRect), box, boxSize.width(), boxSize.height(), includeLogicalLeftEdge, includeLogicalRightEdge);
    }
    if (bleedAvoidance == BackgroundBleedBackgroundOverBorder)
        return style()->getRoundedInnerBorderFor(borderRect, includeLogicalLeftEdge, includeLogicalRightEdge);

    return getBackgroundRoundedRect(borderRect, box, boxSize.width(), boxSize.height(), includeLogicalLeftEdge, includeLogicalRightEdge);
}

static void applyBoxShadowForBackground(GraphicsContext* context, const RenderObject* renderer)
{
    const ShadowList* shadowList = renderer->style()->boxShadow();
    ASSERT(shadowList);
    for (size_t i = shadowList->shadows().size(); i--; ) {
        const ShadowData& boxShadow = shadowList->shadows()[i];
        if (boxShadow.style() != Normal)
            continue;
        FloatSize shadowOffset(boxShadow.x(), boxShadow.y());
        context->setShadow(shadowOffset, boxShadow.blur(), boxShadow.color(),
            DrawLooperBuilder::ShadowRespectsTransforms, DrawLooperBuilder::ShadowIgnoresAlpha);
        return;
    }
}

void RenderBoxModelObject::paintFillLayerExtended(const PaintInfo& paintInfo, const Color& color, const FillLayer* bgLayer, const LayoutRect& rect,
    BackgroundBleedAvoidance bleedAvoidance, InlineFlowBox* box, const LayoutSize& boxSize, CompositeOperator op, RenderObject* backgroundObject)
{
    GraphicsContext* context = paintInfo.context;
    if (context->paintingDisabled() || rect.isEmpty())
        return;

    bool includeLeftEdge = box ? box->includeLogicalLeftEdge() : true;
    bool includeRightEdge = box ? box->includeLogicalRightEdge() : true;

    bool hasRoundedBorder = style()->hasBorderRadius() && (includeLeftEdge || includeRightEdge);
    bool clippedWithLocalScrolling = hasOverflowClip() && bgLayer->attachment() == LocalBackgroundAttachment;
    bool isBorderFill = bgLayer->clip() == BorderFillBox;
    bool isRoot = this->isRoot();

    Color bgColor = color;
    StyleImage* bgImage = bgLayer->image();
    bool shouldPaintBackgroundImage = bgImage && bgImage->canRender(this, style()->effectiveZoom());

    bool forceBackgroundToWhite = false;
    if (document().printing()) {
        if (style()->printColorAdjust() == PrintColorAdjustEconomy)
            forceBackgroundToWhite = true;
        if (document().settings() && document().settings()->shouldPrintBackgrounds())
            forceBackgroundToWhite = false;
    }

    // When printing backgrounds is disabled or using economy mode,
    // change existing background colors and images to a solid white background.
    // If there's no bg color or image, leave it untouched to avoid affecting transparency.
    // We don't try to avoid loading the background images, because this style flag is only set
    // when printing, and at that point we've already loaded the background images anyway. (To avoid
    // loading the background images we'd have to do this check when applying styles rather than
    // while rendering.)
    if (forceBackgroundToWhite) {
        // Note that we can't reuse this variable below because the bgColor might be changed
        bool shouldPaintBackgroundColor = !bgLayer->next() && bgColor.alpha();
        if (shouldPaintBackgroundImage || shouldPaintBackgroundColor) {
            bgColor = Color::white;
            shouldPaintBackgroundImage = false;
        }
    }

    bool colorVisible = bgColor.alpha();

    // Fast path for drawing simple color backgrounds.
    if (!isRoot && !clippedWithLocalScrolling && !shouldPaintBackgroundImage && isBorderFill && !bgLayer->next()) {
        if (!colorVisible)
            return;

        bool boxShadowShouldBeAppliedToBackground = this->boxShadowShouldBeAppliedToBackground(bleedAvoidance, box);
        GraphicsContextStateSaver shadowStateSaver(*context, boxShadowShouldBeAppliedToBackground);
        if (boxShadowShouldBeAppliedToBackground)
            applyBoxShadowForBackground(context, this);

        if (hasRoundedBorder && bleedAvoidance != BackgroundBleedClipBackground) {
            RoundedRect border = backgroundRoundedRectAdjustedForBleedAvoidance(context, rect, bleedAvoidance, box, boxSize, includeLeftEdge, includeRightEdge);
            if (border.isRenderable())
                context->fillRoundedRect(border, bgColor);
            else {
                context->save();
                clipRoundedInnerRect(context, rect, border);
                context->fillRect(border.rect(), bgColor);
                context->restore();
            }
        } else {
            context->fillRect(pixelSnappedIntRect(rect), bgColor);
        }

        return;
    }

    // BorderFillBox radius clipping is taken care of by BackgroundBleedClipBackground
    bool clipToBorderRadius = hasRoundedBorder && !(isBorderFill && bleedAvoidance == BackgroundBleedClipBackground);
    GraphicsContextStateSaver clipToBorderStateSaver(*context, clipToBorderRadius);
    if (clipToBorderRadius) {
        RoundedRect border = isBorderFill ? backgroundRoundedRectAdjustedForBleedAvoidance(context, rect, bleedAvoidance, box, boxSize, includeLeftEdge, includeRightEdge) : getBackgroundRoundedRect(rect, box, boxSize.width(), boxSize.height(), includeLeftEdge, includeRightEdge);

        // Clip to the padding or content boxes as necessary.
        if (bgLayer->clip() == ContentFillBox) {
            border = style()->getRoundedInnerBorderFor(border.rect(),
                paddingTop() + borderTop(), paddingBottom() + borderBottom(), paddingLeft() + borderLeft(), paddingRight() + borderRight(), includeLeftEdge, includeRightEdge);
        } else if (bgLayer->clip() == PaddingFillBox)
            border = style()->getRoundedInnerBorderFor(border.rect(), includeLeftEdge, includeRightEdge);

        clipRoundedInnerRect(context, rect, border);
    }

    int bLeft = includeLeftEdge ? borderLeft() : 0;
    int bRight = includeRightEdge ? borderRight() : 0;
    LayoutUnit pLeft = includeLeftEdge ? paddingLeft() : LayoutUnit();
    LayoutUnit pRight = includeRightEdge ? paddingRight() : LayoutUnit();

    GraphicsContextStateSaver clipWithScrollingStateSaver(*context, clippedWithLocalScrolling);
    LayoutRect scrolledPaintRect = rect;
    if (clippedWithLocalScrolling) {
        // Clip to the overflow area.
        RenderBox* thisBox = toRenderBox(this);
        context->clip(thisBox->overflowClipRect(rect.location()));

        // Adjust the paint rect to reflect a scrolled content box with borders at the ends.
        IntSize offset = thisBox->scrolledContentOffset();
        scrolledPaintRect.move(-offset);
        scrolledPaintRect.setWidth(bLeft + thisBox->scrollWidth() + bRight);
        scrolledPaintRect.setHeight(borderTop() + thisBox->scrollHeight() + borderBottom());
    }

    GraphicsContextStateSaver backgroundClipStateSaver(*context, false);
    IntRect maskRect;

    switch (bgLayer->clip()) {
    case PaddingFillBox:
    case ContentFillBox: {
        if (clipToBorderRadius)
            break;

        // Clip to the padding or content boxes as necessary.
        bool includePadding = bgLayer->clip() == ContentFillBox;
        LayoutRect clipRect = LayoutRect(scrolledPaintRect.x() + bLeft + (includePadding ? pLeft : LayoutUnit()),
            scrolledPaintRect.y() + borderTop() + (includePadding ? paddingTop() : LayoutUnit()),
            scrolledPaintRect.width() - bLeft - bRight - (includePadding ? pLeft + pRight : LayoutUnit()),
            scrolledPaintRect.height() - borderTop() - borderBottom() - (includePadding ? paddingTop() + paddingBottom() : LayoutUnit()));
        backgroundClipStateSaver.save();
        context->clip(clipRect);

        break;
    }
    case TextFillBox: {
        // First figure out how big the mask has to be.  It should be no bigger than what we need
        // to actually render, so we should intersect the dirty rect with the border box of the background.
        maskRect = pixelSnappedIntRect(rect);
        maskRect.intersect(paintInfo.rect);

        // We draw the background into a separate layer, to be later masked with yet another layer
        // holding the text content.
        backgroundClipStateSaver.save();
        context->clip(maskRect);
        context->beginTransparencyLayer(1);

        break;
    }
    case BorderFillBox:
        break;
    default:
        ASSERT_NOT_REACHED();
        break;
    }

    // Only fill with a base color (e.g., white) if we're the root document, since iframes/frames with
    // no background in the child document should show the parent's background.
    bool isOpaqueRoot = false;
    if (isRoot) {
        isOpaqueRoot = true;
        if (!bgLayer->next() && bgColor.hasAlpha() && view()->frameView()) {
            Element* ownerElement = document().ownerElement();
            if (ownerElement) {
                if (!isHTMLFrameElement(*ownerElement)) {
                    // Locate the <body> element using the DOM.  This is easier than trying
                    // to crawl around a render tree with potential :before/:after content and
                    // anonymous blocks created by inline <body> tags etc.  We can locate the <body>
                    // render object very easily via the DOM.
                    HTMLElement* body = document().body();
                    if (body) {
                        // Can't scroll a frameset document anyway.
                        isOpaqueRoot = body->hasLocalName(framesetTag);
                    } else {
                        // SVG documents and XML documents with SVG root nodes are transparent.
                        isOpaqueRoot = !document().hasSVGRootNode();
                    }
                }
            } else
                isOpaqueRoot = !view()->frameView()->isTransparent();
        }
        view()->frameView()->setContentIsOpaque(isOpaqueRoot);
    }

    // Paint the color first underneath all images, culled if background image occludes it.
    // FIXME: In the bgLayer->hasFiniteBounds() case, we could improve the culling test
    // by verifying whether the background image covers the entire layout rect.
    if (!bgLayer->next()) {
        IntRect backgroundRect(pixelSnappedIntRect(scrolledPaintRect));
        bool boxShadowShouldBeAppliedToBackground = this->boxShadowShouldBeAppliedToBackground(bleedAvoidance, box);
        if (boxShadowShouldBeAppliedToBackground || !shouldPaintBackgroundImage || !bgLayer->hasOpaqueImage(this) || !bgLayer->hasRepeatXY() || (isOpaqueRoot && !toRenderBox(this)->height()))  {
            if (!boxShadowShouldBeAppliedToBackground)
                backgroundRect.intersect(paintInfo.rect);

            GraphicsContextStateSaver shadowStateSaver(*context, boxShadowShouldBeAppliedToBackground);
            if (boxShadowShouldBeAppliedToBackground)
                applyBoxShadowForBackground(context, this);

            if (isOpaqueRoot) {
                // If we have an alpha and we are painting the root element, go ahead and blend with the base background color.
                Color baseColor = view()->frameView()->baseBackgroundColor();
                bool shouldClearDocumentBackground = document().settings() && document().settings()->shouldClearDocumentBackground();
                CompositeOperator operation = shouldClearDocumentBackground ? CompositeCopy : context->compositeOperation();

                if (baseColor.alpha()) {
                    if (bgColor.alpha())
                        baseColor = baseColor.blend(bgColor);
                    context->fillRect(backgroundRect, baseColor, operation);
                } else if (bgColor.alpha()) {
                    context->fillRect(backgroundRect, bgColor, operation);
                } else if (shouldClearDocumentBackground) {
                    context->clearRect(backgroundRect);
                }
            } else if (bgColor.alpha()) {
                context->fillRect(backgroundRect, bgColor, context->compositeOperation());
            }
        }
    }

    // no progressive loading of the background image
    if (shouldPaintBackgroundImage) {
        BackgroundImageGeometry geometry;
        calculateBackgroundImageGeometry(paintInfo.paintContainer(), bgLayer, scrolledPaintRect, geometry, backgroundObject);
        geometry.clip(paintInfo.rect);
        if (!geometry.destRect().isEmpty()) {
            CompositeOperator compositeOp = op == CompositeSourceOver ? bgLayer->composite() : op;
            RenderObject* clientForBackgroundImage = backgroundObject ? backgroundObject : this;
            RefPtr<Image> image = bgImage->image(clientForBackgroundImage, geometry.tileSize());
            InterpolationQuality interpolationQuality = chooseInterpolationQuality(context, image.get(), bgLayer, geometry.tileSize());
            if (bgLayer->maskSourceType() == MaskLuminance)
                context->setColorFilter(ColorFilterLuminanceToAlpha);
            InterpolationQuality previousInterpolationQuality = context->imageInterpolationQuality();
            context->setImageInterpolationQuality(interpolationQuality);
            context->drawTiledImage(image.get(), geometry.destRect(), geometry.relativePhase(), geometry.tileSize(),
                compositeOp, bgLayer->blendMode(), geometry.spaceSize());
            context->setImageInterpolationQuality(previousInterpolationQuality);
        }
    }

    if (bgLayer->clip() == TextFillBox) {
        // Create the text mask layer.
        context->setCompositeOperation(CompositeDestinationIn);
        context->beginTransparencyLayer(1);

        // FIXME: Workaround for https://code.google.com/p/skia/issues/detail?id=1291.
        context->clearRect(maskRect);

        // Now draw the text into the mask. We do this by painting using a special paint phase that signals to
        // InlineTextBoxes that they should just add their contents to the clip.
        PaintInfo info(context, maskRect, PaintPhaseTextClip, PaintBehaviorForceBlackText, 0);
        context->setCompositeOperation(CompositeSourceOver);
        if (box) {
            RootInlineBox& root = box->root();
            box->paint(info, LayoutPoint(scrolledPaintRect.x() - box->x(), scrolledPaintRect.y() - box->y()), root.lineTop(), root.lineBottom());
        } else {
            LayoutSize localOffset = isBox() ? toRenderBox(this)->locationOffset() : LayoutSize();
            paint(info, scrolledPaintRect.location() - localOffset);
        }

        context->endLayer();
        context->endLayer();
    }
}

static inline int resolveWidthForRatio(int height, const FloatSize& intrinsicRatio)
{
    return ceilf(height * intrinsicRatio.width() / intrinsicRatio.height());
}

static inline int resolveHeightForRatio(int width, const FloatSize& intrinsicRatio)
{
    return ceilf(width * intrinsicRatio.height() / intrinsicRatio.width());
}

static inline IntSize resolveAgainstIntrinsicWidthOrHeightAndRatio(const IntSize& size, const FloatSize& intrinsicRatio, int useWidth, int useHeight)
{
    if (intrinsicRatio.isEmpty()) {
        if (useWidth)
            return IntSize(useWidth, size.height());
        return IntSize(size.width(), useHeight);
    }

    if (useWidth)
        return IntSize(useWidth, resolveHeightForRatio(useWidth, intrinsicRatio));
    return IntSize(resolveWidthForRatio(useHeight, intrinsicRatio), useHeight);
}

static inline IntSize resolveAgainstIntrinsicRatio(const IntSize& size, const FloatSize& intrinsicRatio)
{
    // Two possible solutions: (size.width(), solutionHeight) or (solutionWidth, size.height())
    // "... must be assumed to be the largest dimensions..." = easiest answer: the rect with the largest surface area.

    int solutionWidth = resolveWidthForRatio(size.height(), intrinsicRatio);
    int solutionHeight = resolveHeightForRatio(size.width(), intrinsicRatio);
    if (solutionWidth <= size.width()) {
        if (solutionHeight <= size.height()) {
            // If both solutions fit, choose the one covering the larger area.
            int areaOne = solutionWidth * size.height();
            int areaTwo = size.width() * solutionHeight;
            if (areaOne < areaTwo)
                return IntSize(size.width(), solutionHeight);
            return IntSize(solutionWidth, size.height());
        }

        // Only the first solution fits.
        return IntSize(solutionWidth, size.height());
    }

    // Only the second solution fits, assert that.
    ASSERT(solutionHeight <= size.height());
    return IntSize(size.width(), solutionHeight);
}

IntSize RenderBoxModelObject::calculateImageIntrinsicDimensions(StyleImage* image, const IntSize& positioningAreaSize, ScaleByEffectiveZoomOrNot shouldScaleOrNot) const
{
    // A generated image without a fixed size, will always return the container size as intrinsic size.
    if (image->isGeneratedImage() && image->usesImageContainerSize())
        return IntSize(positioningAreaSize.width(), positioningAreaSize.height());

    Length intrinsicWidth;
    Length intrinsicHeight;
    FloatSize intrinsicRatio;
    image->computeIntrinsicDimensions(this, intrinsicWidth, intrinsicHeight, intrinsicRatio);

    // Intrinsic dimensions expressed as percentages must be resolved relative to the dimensions of the rectangle
    // that establishes the coordinate system for the 'background-position' property.

    // FIXME: Remove unnecessary rounding when layout is off ints: webkit.org/b/63656
    if (intrinsicWidth.isPercent() && intrinsicHeight.isPercent() && intrinsicRatio.isEmpty()) {
        // Resolve width/height percentages against positioningAreaSize, only if no intrinsic ratio is provided.
        int resolvedWidth = static_cast<int>(round(positioningAreaSize.width() * intrinsicWidth.percent() / 100));
        int resolvedHeight = static_cast<int>(round(positioningAreaSize.height() * intrinsicHeight.percent() / 100));
        return IntSize(resolvedWidth, resolvedHeight);
    }

    IntSize resolvedSize(intrinsicWidth.isFixed() ? intrinsicWidth.value() : 0, intrinsicHeight.isFixed() ? intrinsicHeight.value() : 0);
    IntSize minimumSize(resolvedSize.width() > 0 ? 1 : 0, resolvedSize.height() > 0 ? 1 : 0);
    if (shouldScaleOrNot == ScaleByEffectiveZoom)
        resolvedSize.scale(style()->effectiveZoom());
    resolvedSize.clampToMinimumSize(minimumSize);

    if (!resolvedSize.isEmpty())
        return resolvedSize;

    // If the image has one of either an intrinsic width or an intrinsic height:
    // * and an intrinsic aspect ratio, then the missing dimension is calculated from the given dimension and the ratio.
    // * and no intrinsic aspect ratio, then the missing dimension is assumed to be the size of the rectangle that
    //   establishes the coordinate system for the 'background-position' property.
    if (resolvedSize.width() > 0 || resolvedSize.height() > 0)
        return resolveAgainstIntrinsicWidthOrHeightAndRatio(positioningAreaSize, intrinsicRatio, resolvedSize.width(), resolvedSize.height());

    // If the image has no intrinsic dimensions and has an intrinsic ratio the dimensions must be assumed to be the
    // largest dimensions at that ratio such that neither dimension exceeds the dimensions of the rectangle that
    // establishes the coordinate system for the 'background-position' property.
    if (!intrinsicRatio.isEmpty())
        return resolveAgainstIntrinsicRatio(positioningAreaSize, intrinsicRatio);

    // If the image has no intrinsic ratio either, then the dimensions must be assumed to be the rectangle that
    // establishes the coordinate system for the 'background-position' property.
    return positioningAreaSize;
}

static inline void applySubPixelHeuristicForTileSize(LayoutSize& tileSize, const IntSize& positioningAreaSize)
{
    tileSize.setWidth(positioningAreaSize.width() - tileSize.width() <= 1 ? tileSize.width().ceil() : tileSize.width().floor());
    tileSize.setHeight(positioningAreaSize.height() - tileSize.height() <= 1 ? tileSize.height().ceil() : tileSize.height().floor());
}

IntSize RenderBoxModelObject::calculateFillTileSize(const FillLayer* fillLayer, const IntSize& positioningAreaSize) const
{
    StyleImage* image = fillLayer->image();
    EFillSizeType type = fillLayer->size().type;

    IntSize imageIntrinsicSize = calculateImageIntrinsicDimensions(image, positioningAreaSize, ScaleByEffectiveZoom);
    imageIntrinsicSize.scale(1 / image->imageScaleFactor(), 1 / image->imageScaleFactor());
    switch (type) {
        case SizeLength: {
            LayoutSize tileSize = positioningAreaSize;

            Length layerWidth = fillLayer->size().size.width();
            Length layerHeight = fillLayer->size().size.height();

            if (layerWidth.isFixed())
                tileSize.setWidth(layerWidth.value());
            else if (layerWidth.isPercent())
                tileSize.setWidth(valueForLength(layerWidth, positioningAreaSize.width()));

            if (layerHeight.isFixed())
                tileSize.setHeight(layerHeight.value());
            else if (layerHeight.isPercent())
                tileSize.setHeight(valueForLength(layerHeight, positioningAreaSize.height()));

            applySubPixelHeuristicForTileSize(tileSize, positioningAreaSize);

            // If one of the values is auto we have to use the appropriate
            // scale to maintain our aspect ratio.
            if (layerWidth.isAuto() && !layerHeight.isAuto()) {
                if (imageIntrinsicSize.height())
                    tileSize.setWidth(imageIntrinsicSize.width() * tileSize.height() / imageIntrinsicSize.height());
            } else if (!layerWidth.isAuto() && layerHeight.isAuto()) {
                if (imageIntrinsicSize.width())
                    tileSize.setHeight(imageIntrinsicSize.height() * tileSize.width() / imageIntrinsicSize.width());
            } else if (layerWidth.isAuto() && layerHeight.isAuto()) {
                // If both width and height are auto, use the image's intrinsic size.
                tileSize = imageIntrinsicSize;
            }

            tileSize.clampNegativeToZero();
            return flooredIntSize(tileSize);
        }
        case SizeNone: {
            // If both values are ‘auto’ then the intrinsic width and/or height of the image should be used, if any.
            if (!imageIntrinsicSize.isEmpty())
                return imageIntrinsicSize;

            // If the image has neither an intrinsic width nor an intrinsic height, its size is determined as for ‘contain’.
            type = Contain;
        }
        case Contain:
        case Cover: {
            float horizontalScaleFactor = imageIntrinsicSize.width()
                ? static_cast<float>(positioningAreaSize.width()) / imageIntrinsicSize.width() : 1;
            float verticalScaleFactor = imageIntrinsicSize.height()
                ? static_cast<float>(positioningAreaSize.height()) / imageIntrinsicSize.height() : 1;
            float scaleFactor = type == Contain ? min(horizontalScaleFactor, verticalScaleFactor) : max(horizontalScaleFactor, verticalScaleFactor);
            return IntSize(max(1l, lround(imageIntrinsicSize.width() * scaleFactor)), max(1l, lround(imageIntrinsicSize.height() * scaleFactor)));
       }
    }

    ASSERT_NOT_REACHED();
    return IntSize();
}

void RenderBoxModelObject::BackgroundImageGeometry::setNoRepeatX(int xOffset)
{
    m_destRect.move(max(xOffset, 0), 0);
    m_phase.setX(-min(xOffset, 0));
    m_destRect.setWidth(m_tileSize.width() + min(xOffset, 0));
}
void RenderBoxModelObject::BackgroundImageGeometry::setNoRepeatY(int yOffset)
{
    m_destRect.move(0, max(yOffset, 0));
    m_phase.setY(-min(yOffset, 0));
    m_destRect.setHeight(m_tileSize.height() + min(yOffset, 0));
}

void RenderBoxModelObject::BackgroundImageGeometry::useFixedAttachment(const IntPoint& attachmentPoint)
{
    IntPoint alignedPoint = attachmentPoint;
    m_phase.move(max(alignedPoint.x() - m_destRect.x(), 0), max(alignedPoint.y() - m_destRect.y(), 0));
}

void RenderBoxModelObject::BackgroundImageGeometry::clip(const IntRect& clipRect)
{
    m_destRect.intersect(clipRect);
}

IntPoint RenderBoxModelObject::BackgroundImageGeometry::relativePhase() const
{
    IntPoint phase = m_phase;
    phase += m_destRect.location() - m_destOrigin;
    return phase;
}

bool RenderBoxModelObject::fixedBackgroundPaintsInLocalCoordinates() const
{
    if (!isRoot())
        return false;

    if (view()->frameView() && view()->frameView()->paintBehavior() & PaintBehaviorFlattenCompositingLayers)
        return false;

    RenderLayer* rootLayer = view()->layer();
    if (!rootLayer || rootLayer->compositingState() == NotComposited)
        return false;

    return rootLayer->compositedLayerMapping()->backgroundLayerPaintsFixedRootBackground();
}

static inline int getSpace(int areaSize, int tileSize)
{
    int numberOfTiles = areaSize / tileSize;
    int space = -1;

    if (numberOfTiles > 1)
        space = lroundf((float)(areaSize - numberOfTiles * tileSize) / (numberOfTiles - 1));

    return space;
}

void RenderBoxModelObject::calculateBackgroundImageGeometry(const RenderLayerModelObject* paintContainer, const FillLayer* fillLayer, const LayoutRect& paintRect,
    BackgroundImageGeometry& geometry, RenderObject* backgroundObject) const
{
    LayoutUnit left = 0;
    LayoutUnit top = 0;
    IntSize positioningAreaSize;
    IntRect snappedPaintRect = pixelSnappedIntRect(paintRect);

    // Determine the background positioning area and set destRect to the background painting area.
    // destRect will be adjusted later if the background is non-repeating.
    // FIXME: transforms spec says that fixed backgrounds behave like scroll inside transforms.
    bool fixedAttachment = fillLayer->attachment() == FixedBackgroundAttachment;

#if ENABLE(FAST_MOBILE_SCROLLING)
    if (view()->frameView() && view()->frameView()->shouldAttemptToScrollUsingFastPath()) {
        // As a side effect of an optimization to blit on scroll, we do not honor the CSS
        // property "background-attachment: fixed" because it may result in rendering
        // artifacts. Note, these artifacts only appear if we are blitting on scroll of
        // a page that has fixed background images.
        fixedAttachment = false;
    }
#endif

    if (!fixedAttachment) {
        geometry.setDestRect(snappedPaintRect);

        LayoutUnit right = 0;
        LayoutUnit bottom = 0;
        // Scroll and Local.
        if (fillLayer->origin() != BorderFillBox) {
            left = borderLeft();
            right = borderRight();
            top = borderTop();
            bottom = borderBottom();
            if (fillLayer->origin() == ContentFillBox) {
                left += paddingLeft();
                right += paddingRight();
                top += paddingTop();
                bottom += paddingBottom();
            }
        }

        // The background of the box generated by the root element covers the entire canvas including
        // its margins. Since those were added in already, we have to factor them out when computing
        // the background positioning area.
        if (isRoot()) {
            positioningAreaSize = pixelSnappedIntSize(toRenderBox(this)->size() - LayoutSize(left + right, top + bottom), toRenderBox(this)->location());
            left += marginLeft();
            top += marginTop();
        } else
            positioningAreaSize = pixelSnappedIntSize(paintRect.size() - LayoutSize(left + right, top + bottom), paintRect.location());
    } else {
        geometry.setHasNonLocalGeometry();

        IntRect viewportRect = pixelSnappedIntRect(viewRect());
        if (fixedBackgroundPaintsInLocalCoordinates())
            viewportRect.setLocation(IntPoint());
        else if (FrameView* frameView = view()->frameView())
            viewportRect.setLocation(IntPoint(frameView->scrollOffsetForFixedPosition()));

        if (paintContainer) {
            IntPoint absoluteContainerOffset = roundedIntPoint(paintContainer->localToAbsolute(FloatPoint()));
            viewportRect.moveBy(-absoluteContainerOffset);
        }

        geometry.setDestRect(pixelSnappedIntRect(viewportRect));
        positioningAreaSize = geometry.destRect().size();
    }

    const RenderObject* clientForBackgroundImage = backgroundObject ? backgroundObject : this;
    IntSize fillTileSize = calculateFillTileSize(fillLayer, positioningAreaSize);
    fillLayer->image()->setContainerSizeForRenderer(clientForBackgroundImage, fillTileSize, style()->effectiveZoom());
    geometry.setTileSize(fillTileSize);

    EFillRepeat backgroundRepeatX = fillLayer->repeatX();
    EFillRepeat backgroundRepeatY = fillLayer->repeatY();
    int availableWidth = positioningAreaSize.width() - geometry.tileSize().width();
    int availableHeight = positioningAreaSize.height() - geometry.tileSize().height();

    LayoutUnit computedXPosition = roundedMinimumValueForLength(fillLayer->xPosition(), availableWidth);
    if (backgroundRepeatX == RoundFill && positioningAreaSize.width() > 0 && fillTileSize.width() > 0) {
        long nrTiles = max(1l, lroundf((float)positioningAreaSize.width() / fillTileSize.width()));

        if (fillLayer->size().size.height().isAuto() && backgroundRepeatY != RoundFill) {
            fillTileSize.setHeight(fillTileSize.height() * positioningAreaSize.width() / (nrTiles * fillTileSize.width()));
        }

        fillTileSize.setWidth(positioningAreaSize.width() / nrTiles);
        geometry.setTileSize(fillTileSize);
        geometry.setPhaseX(geometry.tileSize().width() ? geometry.tileSize().width() - roundToInt(computedXPosition + left) % geometry.tileSize().width() : 0);
        geometry.setSpaceSize(IntSize());
    }

    LayoutUnit computedYPosition = roundedMinimumValueForLength(fillLayer->yPosition(), availableHeight);
    if (backgroundRepeatY == RoundFill && positioningAreaSize.height() > 0 && fillTileSize.height() > 0) {
        long nrTiles = max(1l, lroundf((float)positioningAreaSize.height() / fillTileSize.height()));

        if (fillLayer->size().size.width().isAuto() && backgroundRepeatX != RoundFill) {
            fillTileSize.setWidth(fillTileSize.width() * positioningAreaSize.height() / (nrTiles * fillTileSize.height()));
        }

        fillTileSize.setHeight(positioningAreaSize.height() / nrTiles);
        geometry.setTileSize(fillTileSize);
        geometry.setPhaseY(geometry.tileSize().height() ? geometry.tileSize().height() - roundToInt(computedYPosition + top) % geometry.tileSize().height() : 0);
        geometry.setSpaceSize(IntSize());
    }

    if (backgroundRepeatX == RepeatFill) {
        geometry.setPhaseX(geometry.tileSize().width() ? geometry.tileSize().width() - roundToInt(computedXPosition + left) % geometry.tileSize().width() : 0);
        geometry.setSpaceSize(IntSize());
    } else if (backgroundRepeatX == SpaceFill && fillTileSize.width() > 0) {
        int space = getSpace(positioningAreaSize.width(), geometry.tileSize().width());
        int actualWidth = geometry.tileSize().width() + space;

        if (space >= 0) {
            computedXPosition = roundedMinimumValueForLength(Length(), availableWidth);
            geometry.setSpaceSize(IntSize(space, 0));
            geometry.setPhaseX(actualWidth ? actualWidth - roundToInt(computedXPosition + left) % actualWidth : 0);
        } else {
            backgroundRepeatX = NoRepeatFill;
        }
    }
    if (backgroundRepeatX == NoRepeatFill) {
        int xOffset = fillLayer->backgroundXOrigin() == RightEdge ? availableWidth - computedXPosition : computedXPosition;
        geometry.setNoRepeatX(left + xOffset);
        geometry.setSpaceSize(IntSize(0, geometry.spaceSize().height()));
    }

    if (backgroundRepeatY == RepeatFill) {
        geometry.setPhaseY(geometry.tileSize().height() ? geometry.tileSize().height() - roundToInt(computedYPosition + top) % geometry.tileSize().height() : 0);
        geometry.setSpaceSize(IntSize(geometry.spaceSize().width(), 0));
    } else if (backgroundRepeatY == SpaceFill && fillTileSize.height() > 0) {
        int space = getSpace(positioningAreaSize.height(), geometry.tileSize().height());
        int actualHeight = geometry.tileSize().height() + space;

        if (space >= 0) {
            computedYPosition = roundedMinimumValueForLength(Length(), availableHeight);
            geometry.setSpaceSize(IntSize(geometry.spaceSize().width(), space));
            geometry.setPhaseY(actualHeight ? actualHeight - roundToInt(computedYPosition + top) % actualHeight : 0);
        } else {
            backgroundRepeatY = NoRepeatFill;
        }
    }
    if (backgroundRepeatY == NoRepeatFill) {
        int yOffset = fillLayer->backgroundYOrigin() == BottomEdge ? availableHeight - computedYPosition : computedYPosition;
        geometry.setNoRepeatY(top + yOffset);
        geometry.setSpaceSize(IntSize(geometry.spaceSize().width(), 0));
    }

    if (fixedAttachment)
        geometry.useFixedAttachment(snappedPaintRect.location());

    geometry.clip(snappedPaintRect);
    geometry.setDestOrigin(geometry.destRect().location());
}

static LayoutUnit computeBorderImageSide(const BorderImageLength& borderSlice, LayoutUnit borderSide, LayoutUnit imageSide, LayoutUnit boxExtent)
{
    if (borderSlice.isNumber())
        return borderSlice.number() * borderSide;
    if (borderSlice.length().isAuto())
        return imageSide;
    return valueForLength(borderSlice.length(), boxExtent);
}

bool RenderBoxModelObject::paintNinePieceImage(GraphicsContext* graphicsContext, const LayoutRect& rect, const RenderStyle* style,
                                               const NinePieceImage& ninePieceImage, CompositeOperator op)
{
    StyleImage* styleImage = ninePieceImage.image();
    if (!styleImage)
        return false;

    if (!styleImage->isLoaded())
        return true; // Never paint a nine-piece image incrementally, but don't paint the fallback borders either.

    if (!styleImage->canRender(this, style->effectiveZoom()))
        return false;

    // FIXME: border-image is broken with full page zooming when tiling has to happen, since the tiling function
    // doesn't have any understanding of the zoom that is in effect on the tile.
    LayoutRect rectWithOutsets = rect;
    rectWithOutsets.expand(style->imageOutsets(ninePieceImage));
    IntRect borderImageRect = pixelSnappedIntRect(rectWithOutsets);

    IntSize imageSize = calculateImageIntrinsicDimensions(styleImage, borderImageRect.size(), DoNotScaleByEffectiveZoom);

    // If both values are ‘auto’ then the intrinsic width and/or height of the image should be used, if any.
    styleImage->setContainerSizeForRenderer(this, imageSize, style->effectiveZoom());

    int imageWidth = imageSize.width();
    int imageHeight = imageSize.height();

    float imageScaleFactor = styleImage->imageScaleFactor();
    int topSlice = min<int>(imageHeight, valueForLength(ninePieceImage.imageSlices().top(), imageHeight)) * imageScaleFactor;
    int rightSlice = min<int>(imageWidth, valueForLength(ninePieceImage.imageSlices().right(), imageWidth)) * imageScaleFactor;
    int bottomSlice = min<int>(imageHeight, valueForLength(ninePieceImage.imageSlices().bottom(), imageHeight)) * imageScaleFactor;
    int leftSlice = min<int>(imageWidth, valueForLength(ninePieceImage.imageSlices().left(), imageWidth)) * imageScaleFactor;

    ENinePieceImageRule hRule = ninePieceImage.horizontalRule();
    ENinePieceImageRule vRule = ninePieceImage.verticalRule();

    int topWidth = computeBorderImageSide(ninePieceImage.borderSlices().top(), style->borderTopWidth(), topSlice, borderImageRect.height());
    int rightWidth = computeBorderImageSide(ninePieceImage.borderSlices().right(), style->borderRightWidth(), rightSlice, borderImageRect.width());
    int bottomWidth = computeBorderImageSide(ninePieceImage.borderSlices().bottom(), style->borderBottomWidth(), bottomSlice, borderImageRect.height());
    int leftWidth = computeBorderImageSide(ninePieceImage.borderSlices().left(), style->borderLeftWidth(), leftSlice, borderImageRect.width());

    // Reduce the widths if they're too large.
    // The spec says: Given Lwidth as the width of the border image area, Lheight as its height, and Wside as the border image width
    // offset for the side, let f = min(Lwidth/(Wleft+Wright), Lheight/(Wtop+Wbottom)). If f < 1, then all W are reduced by
    // multiplying them by f.
    int borderSideWidth = max(1, leftWidth + rightWidth);
    int borderSideHeight = max(1, topWidth + bottomWidth);
    float borderSideScaleFactor = min((float)borderImageRect.width() / borderSideWidth, (float)borderImageRect.height() / borderSideHeight);
    if (borderSideScaleFactor < 1) {
        topWidth *= borderSideScaleFactor;
        rightWidth *= borderSideScaleFactor;
        bottomWidth *= borderSideScaleFactor;
        leftWidth *= borderSideScaleFactor;
    }

    bool drawLeft = leftSlice > 0 && leftWidth > 0;
    bool drawTop = topSlice > 0 && topWidth > 0;
    bool drawRight = rightSlice > 0 && rightWidth > 0;
    bool drawBottom = bottomSlice > 0 && bottomWidth > 0;
    bool drawMiddle = ninePieceImage.fill() && (imageWidth - leftSlice - rightSlice) > 0 && (borderImageRect.width() - leftWidth - rightWidth) > 0
                      && (imageHeight - topSlice - bottomSlice) > 0 && (borderImageRect.height() - topWidth - bottomWidth) > 0;

    RefPtr<Image> image = styleImage->image(this, imageSize);

    float destinationWidth = borderImageRect.width() - leftWidth - rightWidth;
    float destinationHeight = borderImageRect.height() - topWidth - bottomWidth;

    float sourceWidth = imageWidth - leftSlice - rightSlice;
    float sourceHeight = imageHeight - topSlice - bottomSlice;

    float leftSideScale = drawLeft ? (float)leftWidth / leftSlice : 1;
    float rightSideScale = drawRight ? (float)rightWidth / rightSlice : 1;
    float topSideScale = drawTop ? (float)topWidth / topSlice : 1;
    float bottomSideScale = drawBottom ? (float)bottomWidth / bottomSlice : 1;

    if (drawLeft) {
        // Paint the top and bottom left corners.

        // The top left corner rect is (tx, ty, leftWidth, topWidth)
        // The rect to use from within the image is obtained from our slice, and is (0, 0, leftSlice, topSlice)
        if (drawTop)
            graphicsContext->drawImage(image.get(), IntRect(borderImageRect.location(), IntSize(leftWidth, topWidth)),
                                       LayoutRect(0, 0, leftSlice, topSlice), op);

        // The bottom left corner rect is (tx, ty + h - bottomWidth, leftWidth, bottomWidth)
        // The rect to use from within the image is (0, imageHeight - bottomSlice, leftSlice, botomSlice)
        if (drawBottom)
            graphicsContext->drawImage(image.get(), IntRect(borderImageRect.x(), borderImageRect.maxY() - bottomWidth, leftWidth, bottomWidth),
                                       LayoutRect(0, imageHeight - bottomSlice, leftSlice, bottomSlice), op);

        // Paint the left edge.
        // Have to scale and tile into the border rect.
        if (sourceHeight > 0)
            graphicsContext->drawTiledImage(image.get(), IntRect(borderImageRect.x(), borderImageRect.y() + topWidth, leftWidth, destinationHeight),
                                            IntRect(0, topSlice, leftSlice, sourceHeight),
                                            FloatSize(leftSideScale, leftSideScale), Image::StretchTile, (Image::TileRule)vRule, op);
    }

    if (drawRight) {
        // Paint the top and bottom right corners
        // The top right corner rect is (tx + w - rightWidth, ty, rightWidth, topWidth)
        // The rect to use from within the image is obtained from our slice, and is (imageWidth - rightSlice, 0, rightSlice, topSlice)
        if (drawTop)
            graphicsContext->drawImage(image.get(), IntRect(borderImageRect.maxX() - rightWidth, borderImageRect.y(), rightWidth, topWidth),
                                       LayoutRect(imageWidth - rightSlice, 0, rightSlice, topSlice), op);

        // The bottom right corner rect is (tx + w - rightWidth, ty + h - bottomWidth, rightWidth, bottomWidth)
        // The rect to use from within the image is (imageWidth - rightSlice, imageHeight - bottomSlice, rightSlice, bottomSlice)
        if (drawBottom)
            graphicsContext->drawImage(image.get(), IntRect(borderImageRect.maxX() - rightWidth, borderImageRect.maxY() - bottomWidth, rightWidth, bottomWidth),
                                       LayoutRect(imageWidth - rightSlice, imageHeight - bottomSlice, rightSlice, bottomSlice), op);

        // Paint the right edge.
        if (sourceHeight > 0)
            graphicsContext->drawTiledImage(image.get(), IntRect(borderImageRect.maxX() - rightWidth, borderImageRect.y() + topWidth, rightWidth,
                                            destinationHeight),
                                            IntRect(imageWidth - rightSlice, topSlice, rightSlice, sourceHeight),
                                            FloatSize(rightSideScale, rightSideScale),
                                            Image::StretchTile, (Image::TileRule)vRule, op);
    }

    // Paint the top edge.
    if (drawTop && sourceWidth > 0)
        graphicsContext->drawTiledImage(image.get(), IntRect(borderImageRect.x() + leftWidth, borderImageRect.y(), destinationWidth, topWidth),
                                        IntRect(leftSlice, 0, sourceWidth, topSlice),
                                        FloatSize(topSideScale, topSideScale), (Image::TileRule)hRule, Image::StretchTile, op);

    // Paint the bottom edge.
    if (drawBottom && sourceWidth > 0)
        graphicsContext->drawTiledImage(image.get(), IntRect(borderImageRect.x() + leftWidth, borderImageRect.maxY() - bottomWidth,
                                        destinationWidth, bottomWidth),
                                        IntRect(leftSlice, imageHeight - bottomSlice, sourceWidth, bottomSlice),
                                        FloatSize(bottomSideScale, bottomSideScale),
                                        (Image::TileRule)hRule, Image::StretchTile, op);

    // Paint the middle.
    if (drawMiddle) {
        FloatSize middleScaleFactor(1, 1);
        if (drawTop)
            middleScaleFactor.setWidth(topSideScale);
        else if (drawBottom)
            middleScaleFactor.setWidth(bottomSideScale);
        if (drawLeft)
            middleScaleFactor.setHeight(leftSideScale);
        else if (drawRight)
            middleScaleFactor.setHeight(rightSideScale);

        // For "stretch" rules, just override the scale factor and replace. We only had to do this for the
        // center tile, since sides don't even use the scale factor unless they have a rule other than "stretch".
        // The middle however can have "stretch" specified in one axis but not the other, so we have to
        // correct the scale here.
        if (hRule == StretchImageRule)
            middleScaleFactor.setWidth(destinationWidth / sourceWidth);

        if (vRule == StretchImageRule)
            middleScaleFactor.setHeight(destinationHeight / sourceHeight);

        graphicsContext->drawTiledImage(image.get(),
            IntRect(borderImageRect.x() + leftWidth, borderImageRect.y() + topWidth, destinationWidth, destinationHeight),
            IntRect(leftSlice, topSlice, sourceWidth, sourceHeight),
            middleScaleFactor, (Image::TileRule)hRule, (Image::TileRule)vRule, op);
    }

    return true;
}

class BorderEdge {
public:
    BorderEdge(int edgeWidth, const Color& edgeColor, EBorderStyle edgeStyle, bool edgeIsTransparent, bool edgeIsPresent = true)
        : width(edgeWidth)
        , color(edgeColor)
        , style(edgeStyle)
        , isTransparent(edgeIsTransparent)
        , isPresent(edgeIsPresent)
    {
        if (style == DOUBLE && edgeWidth < 3)
            style = SOLID;
    }

    BorderEdge()
        : width(0)
        , style(BHIDDEN)
        , isTransparent(false)
        , isPresent(false)
    {
    }

    bool hasVisibleColorAndStyle() const { return style > BHIDDEN && !isTransparent; }
    bool shouldRender() const { return isPresent && width && hasVisibleColorAndStyle(); }
    bool presentButInvisible() const { return usedWidth() && !hasVisibleColorAndStyle(); }
    bool obscuresBackgroundEdge(float scale) const
    {
        if (!isPresent || isTransparent || (width * scale) < 2 || color.hasAlpha() || style == BHIDDEN)
            return false;

        if (style == DOTTED || style == DASHED)
            return false;

        if (style == DOUBLE)
            return width >= 5 * scale; // The outer band needs to be >= 2px wide at unit scale.

        return true;
    }
    bool obscuresBackground() const
    {
        if (!isPresent || isTransparent || color.hasAlpha() || style == BHIDDEN)
            return false;

        if (style == DOTTED || style == DASHED || style == DOUBLE)
            return false;

        return true;
    }

    int usedWidth() const { return isPresent ? width : 0; }

    void getDoubleBorderStripeWidths(int& outerWidth, int& innerWidth) const
    {
        int fullWidth = usedWidth();
        outerWidth = fullWidth / 3;
        innerWidth = fullWidth * 2 / 3;

        // We need certain integer rounding results
        if (fullWidth % 3 == 2)
            outerWidth += 1;

        if (fullWidth % 3 == 1)
            innerWidth += 1;
    }

    int width;
    Color color;
    EBorderStyle style;
    bool isTransparent;
    bool isPresent;
};

static bool allCornersClippedOut(const RoundedRect& border, const LayoutRect& clipRect)
{
    LayoutRect boundingRect = border.rect();
    if (clipRect.contains(boundingRect))
        return false;

    RoundedRect::Radii radii = border.radii();

    LayoutRect topLeftRect(boundingRect.location(), radii.topLeft());
    if (clipRect.intersects(topLeftRect))
        return false;

    LayoutRect topRightRect(boundingRect.location(), radii.topRight());
    topRightRect.setX(boundingRect.maxX() - topRightRect.width());
    if (clipRect.intersects(topRightRect))
        return false;

    LayoutRect bottomLeftRect(boundingRect.location(), radii.bottomLeft());
    bottomLeftRect.setY(boundingRect.maxY() - bottomLeftRect.height());
    if (clipRect.intersects(bottomLeftRect))
        return false;

    LayoutRect bottomRightRect(boundingRect.location(), radii.bottomRight());
    bottomRightRect.setX(boundingRect.maxX() - bottomRightRect.width());
    bottomRightRect.setY(boundingRect.maxY() - bottomRightRect.height());
    if (clipRect.intersects(bottomRightRect))
        return false;

    return true;
}

static bool borderWillArcInnerEdge(const LayoutSize& firstRadius, const FloatSize& secondRadius)
{
    return !firstRadius.isZero() || !secondRadius.isZero();
}

enum BorderEdgeFlag {
    TopBorderEdge = 1 << BSTop,
    RightBorderEdge = 1 << BSRight,
    BottomBorderEdge = 1 << BSBottom,
    LeftBorderEdge = 1 << BSLeft,
    AllBorderEdges = TopBorderEdge | BottomBorderEdge | LeftBorderEdge | RightBorderEdge
};

static inline BorderEdgeFlag edgeFlagForSide(BoxSide side)
{
    return static_cast<BorderEdgeFlag>(1 << side);
}

static inline bool includesEdge(BorderEdgeFlags flags, BoxSide side)
{
    return flags & edgeFlagForSide(side);
}

static inline bool includesAdjacentEdges(BorderEdgeFlags flags)
{
    return (flags & (TopBorderEdge | RightBorderEdge)) == (TopBorderEdge | RightBorderEdge)
        || (flags & (RightBorderEdge | BottomBorderEdge)) == (RightBorderEdge | BottomBorderEdge)
        || (flags & (BottomBorderEdge | LeftBorderEdge)) == (BottomBorderEdge | LeftBorderEdge)
        || (flags & (LeftBorderEdge | TopBorderEdge)) == (LeftBorderEdge | TopBorderEdge);
}

inline bool edgesShareColor(const BorderEdge& firstEdge, const BorderEdge& secondEdge)
{
    return firstEdge.color == secondEdge.color;
}

inline bool styleRequiresClipPolygon(EBorderStyle style)
{
    return style == DOTTED || style == DASHED; // These are drawn with a stroke, so we have to clip to get corner miters.
}

static bool borderStyleFillsBorderArea(EBorderStyle style)
{
    return !(style == DOTTED || style == DASHED || style == DOUBLE);
}

static bool borderStyleHasInnerDetail(EBorderStyle style)
{
    return style == GROOVE || style == RIDGE || style == DOUBLE;
}

static bool borderStyleIsDottedOrDashed(EBorderStyle style)
{
    return style == DOTTED || style == DASHED;
}

// OUTSET darkens the bottom and right (and maybe lightens the top and left)
// INSET darkens the top and left (and maybe lightens the bottom and right)
static inline bool borderStyleHasUnmatchedColorsAtCorner(EBorderStyle style, BoxSide side, BoxSide adjacentSide)
{
    // These styles match at the top/left and bottom/right.
    if (style == INSET || style == GROOVE || style == RIDGE || style == OUTSET) {
        const BorderEdgeFlags topRightFlags = edgeFlagForSide(BSTop) | edgeFlagForSide(BSRight);
        const BorderEdgeFlags bottomLeftFlags = edgeFlagForSide(BSBottom) | edgeFlagForSide(BSLeft);

        BorderEdgeFlags flags = edgeFlagForSide(side) | edgeFlagForSide(adjacentSide);
        return flags == topRightFlags || flags == bottomLeftFlags;
    }
    return false;
}

static inline bool colorsMatchAtCorner(BoxSide side, BoxSide adjacentSide, const BorderEdge edges[])
{
    if (edges[side].shouldRender() != edges[adjacentSide].shouldRender())
        return false;

    if (!edgesShareColor(edges[side], edges[adjacentSide]))
        return false;

    return !borderStyleHasUnmatchedColorsAtCorner(edges[side].style, side, adjacentSide);
}


static inline bool colorNeedsAntiAliasAtCorner(BoxSide side, BoxSide adjacentSide, const BorderEdge edges[])
{
    if (!edges[side].color.hasAlpha())
        return false;

    if (edges[side].shouldRender() != edges[adjacentSide].shouldRender())
        return false;

    if (!edgesShareColor(edges[side], edges[adjacentSide]))
        return true;

    return borderStyleHasUnmatchedColorsAtCorner(edges[side].style, side, adjacentSide);
}

// This assumes that we draw in order: top, bottom, left, right.
static inline bool willBeOverdrawn(BoxSide side, BoxSide adjacentSide, const BorderEdge edges[])
{
    switch (side) {
    case BSTop:
    case BSBottom:
        if (edges[adjacentSide].presentButInvisible())
            return false;

        if (!edgesShareColor(edges[side], edges[adjacentSide]) && edges[adjacentSide].color.hasAlpha())
            return false;

        if (!borderStyleFillsBorderArea(edges[adjacentSide].style))
            return false;

        return true;

    case BSLeft:
    case BSRight:
        // These draw last, so are never overdrawn.
        return false;
    }
    return false;
}

static inline bool borderStylesRequireMitre(BoxSide side, BoxSide adjacentSide, EBorderStyle style, EBorderStyle adjacentStyle)
{
    if (style == DOUBLE || adjacentStyle == DOUBLE || adjacentStyle == GROOVE || adjacentStyle == RIDGE)
        return true;

    if (borderStyleIsDottedOrDashed(style) != borderStyleIsDottedOrDashed(adjacentStyle))
        return true;

    if (style != adjacentStyle)
        return true;

    return borderStyleHasUnmatchedColorsAtCorner(style, side, adjacentSide);
}

static bool joinRequiresMitre(BoxSide side, BoxSide adjacentSide, const BorderEdge edges[], bool allowOverdraw)
{
    if ((edges[side].isTransparent && edges[adjacentSide].isTransparent) || !edges[adjacentSide].isPresent)
        return false;

    if (allowOverdraw && willBeOverdrawn(side, adjacentSide, edges))
        return false;

    if (!edgesShareColor(edges[side], edges[adjacentSide]))
        return true;

    if (borderStylesRequireMitre(side, adjacentSide, edges[side].style, edges[adjacentSide].style))
        return true;

    return false;
}

void RenderBoxModelObject::paintOneBorderSide(GraphicsContext* graphicsContext, const RenderStyle* style, const RoundedRect& outerBorder, const RoundedRect& innerBorder,
    const IntRect& sideRect, BoxSide side, BoxSide adjacentSide1, BoxSide adjacentSide2, const BorderEdge edges[], const Path* path,
    BackgroundBleedAvoidance bleedAvoidance, bool includeLogicalLeftEdge, bool includeLogicalRightEdge, bool antialias, const Color* overrideColor)
{
    const BorderEdge& edgeToRender = edges[side];
    ASSERT(edgeToRender.width);
    const BorderEdge& adjacentEdge1 = edges[adjacentSide1];
    const BorderEdge& adjacentEdge2 = edges[adjacentSide2];

    bool mitreAdjacentSide1 = joinRequiresMitre(side, adjacentSide1, edges, !antialias);
    bool mitreAdjacentSide2 = joinRequiresMitre(side, adjacentSide2, edges, !antialias);

    bool adjacentSide1StylesMatch = colorsMatchAtCorner(side, adjacentSide1, edges);
    bool adjacentSide2StylesMatch = colorsMatchAtCorner(side, adjacentSide2, edges);

    const Color& colorToPaint = overrideColor ? *overrideColor : edgeToRender.color;

    if (path) {
        GraphicsContextStateSaver stateSaver(*graphicsContext);
        if (innerBorder.isRenderable())
            clipBorderSidePolygon(graphicsContext, outerBorder, innerBorder, side, adjacentSide1StylesMatch, adjacentSide2StylesMatch);
        else
            clipBorderSideForComplexInnerPath(graphicsContext, outerBorder, innerBorder, side, edges);
        float thickness = max(max(edgeToRender.width, adjacentEdge1.width), adjacentEdge2.width);
        drawBoxSideFromPath(graphicsContext, outerBorder.rect(), *path, edges, edgeToRender.width, thickness, side, style,
            colorToPaint, edgeToRender.style, bleedAvoidance, includeLogicalLeftEdge, includeLogicalRightEdge);
    } else {
        bool clipForStyle = styleRequiresClipPolygon(edgeToRender.style) && (mitreAdjacentSide1 || mitreAdjacentSide2);
        bool clipAdjacentSide1 = colorNeedsAntiAliasAtCorner(side, adjacentSide1, edges) && mitreAdjacentSide1;
        bool clipAdjacentSide2 = colorNeedsAntiAliasAtCorner(side, adjacentSide2, edges) && mitreAdjacentSide2;
        bool shouldClip = clipForStyle || clipAdjacentSide1 || clipAdjacentSide2;

        GraphicsContextStateSaver clipStateSaver(*graphicsContext, shouldClip);
        if (shouldClip) {
            bool aliasAdjacentSide1 = clipAdjacentSide1 || (clipForStyle && mitreAdjacentSide1);
            bool aliasAdjacentSide2 = clipAdjacentSide2 || (clipForStyle && mitreAdjacentSide2);
            clipBorderSidePolygon(graphicsContext, outerBorder, innerBorder, side, !aliasAdjacentSide1, !aliasAdjacentSide2);
            // Since we clipped, no need to draw with a mitre.
            mitreAdjacentSide1 = false;
            mitreAdjacentSide2 = false;
        }

        drawLineForBoxSide(graphicsContext, sideRect.x(), sideRect.y(), sideRect.maxX(), sideRect.maxY(), side, colorToPaint, edgeToRender.style,
                mitreAdjacentSide1 ? adjacentEdge1.width : 0, mitreAdjacentSide2 ? adjacentEdge2.width : 0, antialias);
    }
}

static IntRect calculateSideRect(const RoundedRect& outerBorder, const BorderEdge edges[], int side)
{
    IntRect sideRect = outerBorder.rect();
    int width = edges[side].width;

    if (side == BSTop)
        sideRect.setHeight(width);
    else if (side == BSBottom)
        sideRect.shiftYEdgeTo(sideRect.maxY() - width);
    else if (side == BSLeft)
        sideRect.setWidth(width);
    else
        sideRect.shiftXEdgeTo(sideRect.maxX() - width);

    return sideRect;
}

void RenderBoxModelObject::paintBorderSides(GraphicsContext* graphicsContext, const RenderStyle* style, const RoundedRect& outerBorder, const RoundedRect& innerBorder,
    const IntPoint& innerBorderAdjustment, const BorderEdge edges[], BorderEdgeFlags edgeSet, BackgroundBleedAvoidance bleedAvoidance,
    bool includeLogicalLeftEdge, bool includeLogicalRightEdge, bool antialias, const Color* overrideColor)
{
    bool renderRadii = outerBorder.isRounded();

    Path roundedPath;
    if (renderRadii)
        roundedPath.addRoundedRect(outerBorder);

    // The inner border adjustment for bleed avoidance mode BackgroundBleedBackgroundOverBorder
    // is only applied to sideRect, which is okay since BackgroundBleedBackgroundOverBorder
    // is only to be used for solid borders and the shape of the border painted by drawBoxSideFromPath
    // only depends on sideRect when painting solid borders.

    if (edges[BSTop].shouldRender() && includesEdge(edgeSet, BSTop)) {
        IntRect sideRect = outerBorder.rect();
        sideRect.setHeight(edges[BSTop].width + innerBorderAdjustment.y());

        bool usePath = renderRadii && (borderStyleHasInnerDetail(edges[BSTop].style) || borderWillArcInnerEdge(innerBorder.radii().topLeft(), innerBorder.radii().topRight()));
        paintOneBorderSide(graphicsContext, style, outerBorder, innerBorder, sideRect, BSTop, BSLeft, BSRight, edges, usePath ? &roundedPath : 0, bleedAvoidance, includeLogicalLeftEdge, includeLogicalRightEdge, antialias, overrideColor);
    }

    if (edges[BSBottom].shouldRender() && includesEdge(edgeSet, BSBottom)) {
        IntRect sideRect = outerBorder.rect();
        sideRect.shiftYEdgeTo(sideRect.maxY() - edges[BSBottom].width - innerBorderAdjustment.y());

        bool usePath = renderRadii && (borderStyleHasInnerDetail(edges[BSBottom].style) || borderWillArcInnerEdge(innerBorder.radii().bottomLeft(), innerBorder.radii().bottomRight()));
        paintOneBorderSide(graphicsContext, style, outerBorder, innerBorder, sideRect, BSBottom, BSLeft, BSRight, edges, usePath ? &roundedPath : 0, bleedAvoidance, includeLogicalLeftEdge, includeLogicalRightEdge, antialias, overrideColor);
    }

    if (edges[BSLeft].shouldRender() && includesEdge(edgeSet, BSLeft)) {
        IntRect sideRect = outerBorder.rect();
        sideRect.setWidth(edges[BSLeft].width + innerBorderAdjustment.x());

        bool usePath = renderRadii && (borderStyleHasInnerDetail(edges[BSLeft].style) || borderWillArcInnerEdge(innerBorder.radii().bottomLeft(), innerBorder.radii().topLeft()));
        paintOneBorderSide(graphicsContext, style, outerBorder, innerBorder, sideRect, BSLeft, BSTop, BSBottom, edges, usePath ? &roundedPath : 0, bleedAvoidance, includeLogicalLeftEdge, includeLogicalRightEdge, antialias, overrideColor);
    }

    if (edges[BSRight].shouldRender() && includesEdge(edgeSet, BSRight)) {
        IntRect sideRect = outerBorder.rect();
        sideRect.shiftXEdgeTo(sideRect.maxX() - edges[BSRight].width - innerBorderAdjustment.x());

        bool usePath = renderRadii && (borderStyleHasInnerDetail(edges[BSRight].style) || borderWillArcInnerEdge(innerBorder.radii().bottomRight(), innerBorder.radii().topRight()));
        paintOneBorderSide(graphicsContext, style, outerBorder, innerBorder, sideRect, BSRight, BSTop, BSBottom, edges, usePath ? &roundedPath : 0, bleedAvoidance, includeLogicalLeftEdge, includeLogicalRightEdge, antialias, overrideColor);
    }
}

void RenderBoxModelObject::paintTranslucentBorderSides(GraphicsContext* graphicsContext, const RenderStyle* style, const RoundedRect& outerBorder, const RoundedRect& innerBorder, const IntPoint& innerBorderAdjustment,
    const BorderEdge edges[], BorderEdgeFlags edgesToDraw, BackgroundBleedAvoidance bleedAvoidance, bool includeLogicalLeftEdge, bool includeLogicalRightEdge, bool antialias)
{
    // willBeOverdrawn assumes that we draw in order: top, bottom, left, right.
    // This is different from BoxSide enum order.
    static const BoxSide paintOrder[] = { BSTop, BSBottom, BSLeft, BSRight };

    while (edgesToDraw) {
        // Find undrawn edges sharing a color.
        Color commonColor;

        BorderEdgeFlags commonColorEdgeSet = 0;
        for (size_t i = 0; i < sizeof(paintOrder) / sizeof(paintOrder[0]); ++i) {
            BoxSide currSide = paintOrder[i];
            if (!includesEdge(edgesToDraw, currSide))
                continue;

            bool includeEdge;
            if (!commonColorEdgeSet) {
                commonColor = edges[currSide].color;
                includeEdge = true;
            } else
                includeEdge = edges[currSide].color == commonColor;

            if (includeEdge)
                commonColorEdgeSet |= edgeFlagForSide(currSide);
        }

        bool useTransparencyLayer = includesAdjacentEdges(commonColorEdgeSet) && commonColor.hasAlpha();
        if (useTransparencyLayer) {
            graphicsContext->beginTransparencyLayer(static_cast<float>(commonColor.alpha()) / 255);
            commonColor = Color(commonColor.red(), commonColor.green(), commonColor.blue());
        }

        paintBorderSides(graphicsContext, style, outerBorder, innerBorder, innerBorderAdjustment, edges, commonColorEdgeSet, bleedAvoidance, includeLogicalLeftEdge, includeLogicalRightEdge, antialias, &commonColor);

        if (useTransparencyLayer)
            graphicsContext->endLayer();

        edgesToDraw &= ~commonColorEdgeSet;
    }
}

void RenderBoxModelObject::paintBorder(const PaintInfo& info, const LayoutRect& rect, const RenderStyle* style,
                                       BackgroundBleedAvoidance bleedAvoidance, bool includeLogicalLeftEdge, bool includeLogicalRightEdge)
{
    GraphicsContext* graphicsContext = info.context;
    // border-image is not affected by border-radius.
    if (paintNinePieceImage(graphicsContext, rect, style, style->borderImage()))
        return;

    if (graphicsContext->paintingDisabled())
        return;

    BorderEdge edges[4];
    getBorderEdgeInfo(edges, style, includeLogicalLeftEdge, includeLogicalRightEdge);
    RoundedRect outerBorder = style->getRoundedBorderFor(rect, includeLogicalLeftEdge, includeLogicalRightEdge);
    RoundedRect innerBorder = style->getRoundedInnerBorderFor(borderInnerRectAdjustedForBleedAvoidance(graphicsContext, rect, bleedAvoidance), includeLogicalLeftEdge, includeLogicalRightEdge);

    bool haveAlphaColor = false;
    bool haveAllSolidEdges = true;
    bool haveAllDoubleEdges = true;
    int numEdgesVisible = 4;
    bool allEdgesShareColor = true;
    bool allEdgesShareWidth = true;
    int firstVisibleEdge = -1;
    BorderEdgeFlags edgesToDraw = 0;

    for (int i = BSTop; i <= BSLeft; ++i) {
        const BorderEdge& currEdge = edges[i];

        if (edges[i].shouldRender())
            edgesToDraw |= edgeFlagForSide(static_cast<BoxSide>(i));

        if (currEdge.presentButInvisible()) {
            --numEdgesVisible;
            allEdgesShareColor = false;
            allEdgesShareWidth = false;
            continue;
        }

        if (!currEdge.shouldRender()) {
            --numEdgesVisible;
            continue;
        }

        if (firstVisibleEdge == -1) {
            firstVisibleEdge = i;
        } else {
            if (currEdge.color != edges[firstVisibleEdge].color)
                allEdgesShareColor = false;
            if (currEdge.width != edges[firstVisibleEdge].width)
                allEdgesShareWidth = false;
        }

        if (currEdge.color.hasAlpha())
            haveAlphaColor = true;

        if (currEdge.style != SOLID)
            haveAllSolidEdges = false;

        if (currEdge.style != DOUBLE)
            haveAllDoubleEdges = false;
    }

    // If no corner intersects the clip region, we can pretend outerBorder is
    // rectangular to improve performance.
    if (haveAllSolidEdges && outerBorder.isRounded() && allCornersClippedOut(outerBorder, info.rect))
        outerBorder.setRadii(RoundedRect::Radii());

    // isRenderable() check avoids issue described in https://bugs.webkit.org/show_bug.cgi?id=38787
    if ((haveAllSolidEdges || haveAllDoubleEdges) && allEdgesShareColor && innerBorder.isRenderable()) {
        // Fast path for drawing all solid edges and all unrounded double edges

        if (numEdgesVisible == 4 && (outerBorder.isRounded() || haveAlphaColor)
            && (haveAllSolidEdges || (!outerBorder.isRounded() && !innerBorder.isRounded()))) {
            Path path;

            if (outerBorder.isRounded() && allEdgesShareWidth) {

                // Very fast path for single stroked round rect with circular corners

                graphicsContext->fillBetweenRoundedRects(outerBorder, innerBorder, edges[firstVisibleEdge].color);
                return;
            }
            if (outerBorder.isRounded() && bleedAvoidance != BackgroundBleedClipBackground)
                path.addRoundedRect(outerBorder);
            else
                path.addRect(outerBorder.rect());

            if (haveAllDoubleEdges) {
                IntRect innerThirdRect = outerBorder.rect();
                IntRect outerThirdRect = outerBorder.rect();
                for (int side = BSTop; side <= BSLeft; ++side) {
                    int outerWidth;
                    int innerWidth;
                    edges[side].getDoubleBorderStripeWidths(outerWidth, innerWidth);

                    if (side == BSTop) {
                        innerThirdRect.shiftYEdgeTo(innerThirdRect.y() + innerWidth);
                        outerThirdRect.shiftYEdgeTo(outerThirdRect.y() + outerWidth);
                    } else if (side == BSBottom) {
                        innerThirdRect.setHeight(innerThirdRect.height() - innerWidth);
                        outerThirdRect.setHeight(outerThirdRect.height() - outerWidth);
                    } else if (side == BSLeft) {
                        innerThirdRect.shiftXEdgeTo(innerThirdRect.x() + innerWidth);
                        outerThirdRect.shiftXEdgeTo(outerThirdRect.x() + outerWidth);
                    } else {
                        innerThirdRect.setWidth(innerThirdRect.width() - innerWidth);
                        outerThirdRect.setWidth(outerThirdRect.width() - outerWidth);
                    }
                }

                RoundedRect outerThird = outerBorder;
                RoundedRect innerThird = innerBorder;
                innerThird.setRect(innerThirdRect);
                outerThird.setRect(outerThirdRect);

                if (outerThird.isRounded() && bleedAvoidance != BackgroundBleedClipBackground)
                    path.addRoundedRect(outerThird);
                else
                    path.addRect(outerThird.rect());

                if (innerThird.isRounded() && bleedAvoidance != BackgroundBleedClipBackground)
                    path.addRoundedRect(innerThird);
                else
                    path.addRect(innerThird.rect());
            }

            if (innerBorder.isRounded())
                path.addRoundedRect(innerBorder);
            else
                path.addRect(innerBorder.rect());

            graphicsContext->setFillRule(RULE_EVENODD);
            graphicsContext->setFillColor(edges[firstVisibleEdge].color);
            graphicsContext->fillPath(path);
            return;
        }
        // Avoid creating transparent layers
        if (haveAllSolidEdges && numEdgesVisible != 4 && !outerBorder.isRounded() && haveAlphaColor) {
            Path path;

            for (int i = BSTop; i <= BSLeft; ++i) {
                const BorderEdge& currEdge = edges[i];
                if (currEdge.shouldRender()) {
                    IntRect sideRect = calculateSideRect(outerBorder, edges, i);
                    path.addRect(sideRect);
                }
            }

            graphicsContext->setFillRule(RULE_NONZERO);
            graphicsContext->setFillColor(edges[firstVisibleEdge].color);
            graphicsContext->fillPath(path);
            return;
        }
    }

    bool clipToOuterBorder = outerBorder.isRounded();
    GraphicsContextStateSaver stateSaver(*graphicsContext, clipToOuterBorder);
    if (clipToOuterBorder) {
        // Clip to the inner and outer radii rects.
        if (bleedAvoidance != BackgroundBleedClipBackground)
            graphicsContext->clipRoundedRect(outerBorder);
        // isRenderable() check avoids issue described in https://bugs.webkit.org/show_bug.cgi?id=38787
        // The inside will be clipped out later (in clipBorderSideForComplexInnerPath)
        if (innerBorder.isRenderable() && !innerBorder.isEmpty())
            graphicsContext->clipOutRoundedRect(innerBorder);
    }

    // If only one edge visible antialiasing doesn't create seams
    bool antialias = shouldAntialiasLines(graphicsContext) || numEdgesVisible == 1;
    RoundedRect unadjustedInnerBorder = (bleedAvoidance == BackgroundBleedBackgroundOverBorder) ? style->getRoundedInnerBorderFor(rect, includeLogicalLeftEdge, includeLogicalRightEdge) : innerBorder;
    IntPoint innerBorderAdjustment(innerBorder.rect().x() - unadjustedInnerBorder.rect().x(), innerBorder.rect().y() - unadjustedInnerBorder.rect().y());
    if (haveAlphaColor)
        paintTranslucentBorderSides(graphicsContext, style, outerBorder, unadjustedInnerBorder, innerBorderAdjustment, edges, edgesToDraw, bleedAvoidance, includeLogicalLeftEdge, includeLogicalRightEdge, antialias);
    else
        paintBorderSides(graphicsContext, style, outerBorder, unadjustedInnerBorder, innerBorderAdjustment, edges, edgesToDraw, bleedAvoidance, includeLogicalLeftEdge, includeLogicalRightEdge, antialias);
}

void RenderBoxModelObject::drawBoxSideFromPath(GraphicsContext* graphicsContext, const LayoutRect& borderRect, const Path& borderPath, const BorderEdge edges[],
    float thickness, float drawThickness, BoxSide side, const RenderStyle* style, Color color, EBorderStyle borderStyle, BackgroundBleedAvoidance bleedAvoidance,
    bool includeLogicalLeftEdge, bool includeLogicalRightEdge)
{
    if (thickness <= 0)
        return;

    if (borderStyle == DOUBLE && thickness < 3)
        borderStyle = SOLID;

    switch (borderStyle) {
    case BNONE:
    case BHIDDEN:
        return;
    case DOTTED:
    case DASHED: {
        graphicsContext->setStrokeColor(color);

        // The stroke is doubled here because the provided path is the
        // outside edge of the border so half the stroke is clipped off.
        // The extra multiplier is so that the clipping mask can antialias
        // the edges to prevent jaggies.
        graphicsContext->setStrokeThickness(drawThickness * 2 * 1.1f);
        graphicsContext->setStrokeStyle(borderStyle == DASHED ? DashedStroke : DottedStroke);

        // If the number of dashes that fit in the path is odd and non-integral then we
        // will have an awkwardly-sized dash at the end of the path. To try to avoid that
        // here, we simply make the whitespace dashes ever so slightly bigger.
        // FIXME: This could be even better if we tried to manipulate the dash offset
        // and possibly the gapLength to get the corners dash-symmetrical.
        float dashLength = thickness * ((borderStyle == DASHED) ? 3.0f : 1.0f);
        float gapLength = dashLength;
        float numberOfDashes = borderPath.length() / dashLength;
        // Don't try to show dashes if we have less than 2 dashes + 2 gaps.
        // FIXME: should do this test per side.
        if (numberOfDashes >= 4) {
            bool evenNumberOfFullDashes = !((int)numberOfDashes % 2);
            bool integralNumberOfDashes = !(numberOfDashes - (int)numberOfDashes);
            if (!evenNumberOfFullDashes && !integralNumberOfDashes) {
                float numberOfGaps = numberOfDashes / 2;
                gapLength += (dashLength  / numberOfGaps);
            }

            DashArray lineDash;
            lineDash.append(dashLength);
            lineDash.append(gapLength);
            graphicsContext->setLineDash(lineDash, dashLength);
        }

        // FIXME: stroking the border path causes issues with tight corners:
        // https://bugs.webkit.org/show_bug.cgi?id=58711
        // Also, to get the best appearance we should stroke a path between the two borders.
        graphicsContext->strokePath(borderPath);
        return;
    }
    case DOUBLE: {
        // Get the inner border rects for both the outer border line and the inner border line
        int outerBorderTopWidth;
        int innerBorderTopWidth;
        edges[BSTop].getDoubleBorderStripeWidths(outerBorderTopWidth, innerBorderTopWidth);

        int outerBorderRightWidth;
        int innerBorderRightWidth;
        edges[BSRight].getDoubleBorderStripeWidths(outerBorderRightWidth, innerBorderRightWidth);

        int outerBorderBottomWidth;
        int innerBorderBottomWidth;
        edges[BSBottom].getDoubleBorderStripeWidths(outerBorderBottomWidth, innerBorderBottomWidth);

        int outerBorderLeftWidth;
        int innerBorderLeftWidth;
        edges[BSLeft].getDoubleBorderStripeWidths(outerBorderLeftWidth, innerBorderLeftWidth);

        // Draw inner border line
        {
            GraphicsContextStateSaver stateSaver(*graphicsContext);
            RoundedRect innerClip = style->getRoundedInnerBorderFor(borderRect,
                innerBorderTopWidth, innerBorderBottomWidth, innerBorderLeftWidth, innerBorderRightWidth,
                includeLogicalLeftEdge, includeLogicalRightEdge);

            graphicsContext->clipRoundedRect(innerClip);
            drawBoxSideFromPath(graphicsContext, borderRect, borderPath, edges, thickness, drawThickness, side, style, color, SOLID, bleedAvoidance, includeLogicalLeftEdge, includeLogicalRightEdge);
        }

        // Draw outer border line
        {
            GraphicsContextStateSaver stateSaver(*graphicsContext);
            LayoutRect outerRect = borderRect;
            if (bleedAvoidance == BackgroundBleedClipBackground) {
                outerRect.inflate(1);
                ++outerBorderTopWidth;
                ++outerBorderBottomWidth;
                ++outerBorderLeftWidth;
                ++outerBorderRightWidth;
            }

            RoundedRect outerClip = style->getRoundedInnerBorderFor(outerRect,
                outerBorderTopWidth, outerBorderBottomWidth, outerBorderLeftWidth, outerBorderRightWidth,
                includeLogicalLeftEdge, includeLogicalRightEdge);
            graphicsContext->clipOutRoundedRect(outerClip);
            drawBoxSideFromPath(graphicsContext, borderRect, borderPath, edges, thickness, drawThickness, side, style, color, SOLID, bleedAvoidance, includeLogicalLeftEdge, includeLogicalRightEdge);
        }
        return;
    }
    case RIDGE:
    case GROOVE:
    {
        EBorderStyle s1;
        EBorderStyle s2;
        if (borderStyle == GROOVE) {
            s1 = INSET;
            s2 = OUTSET;
        } else {
            s1 = OUTSET;
            s2 = INSET;
        }

        // Paint full border
        drawBoxSideFromPath(graphicsContext, borderRect, borderPath, edges, thickness, drawThickness, side, style, color, s1, bleedAvoidance, includeLogicalLeftEdge, includeLogicalRightEdge);

        // Paint inner only
        GraphicsContextStateSaver stateSaver(*graphicsContext);
        LayoutUnit topWidth = edges[BSTop].usedWidth() / 2;
        LayoutUnit bottomWidth = edges[BSBottom].usedWidth() / 2;
        LayoutUnit leftWidth = edges[BSLeft].usedWidth() / 2;
        LayoutUnit rightWidth = edges[BSRight].usedWidth() / 2;

        RoundedRect clipRect = style->getRoundedInnerBorderFor(borderRect,
            topWidth, bottomWidth, leftWidth, rightWidth,
            includeLogicalLeftEdge, includeLogicalRightEdge);

        graphicsContext->clipRoundedRect(clipRect);
        drawBoxSideFromPath(graphicsContext, borderRect, borderPath, edges, thickness, drawThickness, side, style, color, s2, bleedAvoidance, includeLogicalLeftEdge, includeLogicalRightEdge);
        return;
    }
    case INSET:
        if (side == BSTop || side == BSLeft)
            color = color.dark();
        break;
    case OUTSET:
        if (side == BSBottom || side == BSRight)
            color = color.dark();
        break;
    default:
        break;
    }

    graphicsContext->setStrokeStyle(NoStroke);
    graphicsContext->setFillColor(color);
    graphicsContext->drawRect(pixelSnappedIntRect(borderRect));
}

void RenderBoxModelObject::clipBorderSidePolygon(GraphicsContext* graphicsContext, const RoundedRect& outerBorder, const RoundedRect& innerBorder,
                                                 BoxSide side, bool firstEdgeMatches, bool secondEdgeMatches)
{
    FloatPoint quad[4];

    const LayoutRect& outerRect = outerBorder.rect();
    const LayoutRect& innerRect = innerBorder.rect();

    FloatPoint centerPoint(innerRect.location().x().toFloat() + innerRect.width().toFloat() / 2, innerRect.location().y().toFloat() + innerRect.height().toFloat() / 2);

    // For each side, create a quad that encompasses all parts of that side that may draw,
    // including areas inside the innerBorder.
    //
    //         0----------------3
    //       0  \              /  0
    //       |\  1----------- 2  /|
    //       | 1                1 |
    //       | |                | |
    //       | |                | |
    //       | 2                2 |
    //       |/  1------------2  \|
    //       3  /              \  3
    //         0----------------3
    //
    switch (side) {
    case BSTop:
        quad[0] = outerRect.minXMinYCorner();
        quad[1] = innerRect.minXMinYCorner();
        quad[2] = innerRect.maxXMinYCorner();
        quad[3] = outerRect.maxXMinYCorner();

        if (!innerBorder.radii().topLeft().isZero()) {
            findIntersection(quad[0], quad[1],
                FloatPoint(
                    quad[1].x() + innerBorder.radii().topLeft().width(),
                    quad[1].y()),
                FloatPoint(
                    quad[1].x(),
                    quad[1].y() + innerBorder.radii().topLeft().height()),
                quad[1]);
        }

        if (!innerBorder.radii().topRight().isZero()) {
            findIntersection(quad[3], quad[2],
                FloatPoint(
                    quad[2].x() - innerBorder.radii().topRight().width(),
                    quad[2].y()),
                FloatPoint(
                    quad[2].x(),
                    quad[2].y() + innerBorder.radii().topRight().height()),
                quad[2]);
        }
        break;

    case BSLeft:
        quad[0] = outerRect.minXMinYCorner();
        quad[1] = innerRect.minXMinYCorner();
        quad[2] = innerRect.minXMaxYCorner();
        quad[3] = outerRect.minXMaxYCorner();

        if (!innerBorder.radii().topLeft().isZero()) {
            findIntersection(quad[0], quad[1],
                FloatPoint(
                    quad[1].x() + innerBorder.radii().topLeft().width(),
                    quad[1].y()),
                FloatPoint(
                    quad[1].x(),
                    quad[1].y() + innerBorder.radii().topLeft().height()),
                quad[1]);
        }

        if (!innerBorder.radii().bottomLeft().isZero()) {
            findIntersection(quad[3], quad[2],
                FloatPoint(
                    quad[2].x() + innerBorder.radii().bottomLeft().width(),
                    quad[2].y()),
                FloatPoint(
                    quad[2].x(),
                    quad[2].y() - innerBorder.radii().bottomLeft().height()),
                quad[2]);
        }
        break;

    case BSBottom:
        quad[0] = outerRect.minXMaxYCorner();
        quad[1] = innerRect.minXMaxYCorner();
        quad[2] = innerRect.maxXMaxYCorner();
        quad[3] = outerRect.maxXMaxYCorner();

        if (!innerBorder.radii().bottomLeft().isZero()) {
            findIntersection(quad[0], quad[1],
                FloatPoint(
                    quad[1].x() + innerBorder.radii().bottomLeft().width(),
                    quad[1].y()),
                FloatPoint(
                    quad[1].x(),
                    quad[1].y() - innerBorder.radii().bottomLeft().height()),
                quad[1]);
        }

        if (!innerBorder.radii().bottomRight().isZero()) {
            findIntersection(quad[3], quad[2],
                FloatPoint(
                    quad[2].x() - innerBorder.radii().bottomRight().width(),
                    quad[2].y()),
                FloatPoint(
                    quad[2].x(),
                    quad[2].y() - innerBorder.radii().bottomRight().height()),
                quad[2]);
        }
        break;

    case BSRight:
        quad[0] = outerRect.maxXMinYCorner();
        quad[1] = innerRect.maxXMinYCorner();
        quad[2] = innerRect.maxXMaxYCorner();
        quad[3] = outerRect.maxXMaxYCorner();

        if (!innerBorder.radii().topRight().isZero()) {
            findIntersection(quad[0], quad[1],
                FloatPoint(
                    quad[1].x() - innerBorder.radii().topRight().width(),
                    quad[1].y()),
                FloatPoint(
                    quad[1].x(),
                    quad[1].y() + innerBorder.radii().topRight().height()),
                quad[1]);
        }

        if (!innerBorder.radii().bottomRight().isZero()) {
            findIntersection(quad[3], quad[2],
                FloatPoint(
                    quad[2].x() - innerBorder.radii().bottomRight().width(),
                    quad[2].y()),
                FloatPoint(
                    quad[2].x(),
                    quad[2].y() - innerBorder.radii().bottomRight().height()),
                quad[2]);
        }
        break;
    }

    // If the border matches both of its adjacent sides, don't anti-alias the clip, and
    // if neither side matches, anti-alias the clip.
    if (firstEdgeMatches == secondEdgeMatches) {
        graphicsContext->clipConvexPolygon(4, quad, !firstEdgeMatches);
        return;
    }

    // If antialiasing settings for the first edge and second edge is different,
    // they have to be addressed separately. We do this by breaking the quad into
    // two parallelograms, made by moving quad[1] and quad[2].
    float ax = quad[1].x() - quad[0].x();
    float ay = quad[1].y() - quad[0].y();
    float bx = quad[2].x() - quad[1].x();
    float by = quad[2].y() - quad[1].y();
    float cx = quad[3].x() - quad[2].x();
    float cy = quad[3].y() - quad[2].y();

    const static float kEpsilon = 1e-2f;
    float r1, r2;
    if (fabsf(bx) < kEpsilon && fabsf(by) < kEpsilon) {
        // The quad was actually a triangle.
        r1 = r2 = 1.0f;
    } else {
        // Extend parallelogram a bit to hide calculation error
        const static float kExtendFill = 1e-2f;

        r1 = (-ax * by + ay * bx) / (cx * by - cy * bx) + kExtendFill;
        r2 = (-cx * by + cy * bx) / (ax * by - ay * bx) + kExtendFill;
    }

    FloatPoint firstQuad[4];
    firstQuad[0] = quad[0];
    firstQuad[1] = quad[1];
    firstQuad[2] = FloatPoint(quad[3].x() + r2 * ax, quad[3].y() + r2 * ay);
    firstQuad[3] = quad[3];
    graphicsContext->clipConvexPolygon(4, firstQuad, !firstEdgeMatches);

    FloatPoint secondQuad[4];
    secondQuad[0] = quad[0];
    secondQuad[1] = FloatPoint(quad[0].x() - r1 * cx, quad[0].y() - r1 * cy);
    secondQuad[2] = quad[2];
    secondQuad[3] = quad[3];
    graphicsContext->clipConvexPolygon(4, secondQuad, !secondEdgeMatches);
}

static IntRect calculateSideRectIncludingInner(const RoundedRect& outerBorder, const BorderEdge edges[], BoxSide side)
{
    IntRect sideRect = outerBorder.rect();
    int width;

    switch (side) {
    case BSTop:
        width = sideRect.height() - edges[BSBottom].width;
        sideRect.setHeight(width);
        break;
    case BSBottom:
        width = sideRect.height() - edges[BSTop].width;
        sideRect.shiftYEdgeTo(sideRect.maxY() - width);
        break;
    case BSLeft:
        width = sideRect.width() - edges[BSRight].width;
        sideRect.setWidth(width);
        break;
    case BSRight:
        width = sideRect.width() - edges[BSLeft].width;
        sideRect.shiftXEdgeTo(sideRect.maxX() - width);
        break;
    }

    return sideRect;
}

static RoundedRect calculateAdjustedInnerBorder(const RoundedRect&innerBorder, BoxSide side)
{
    // Expand the inner border as necessary to make it a rounded rect (i.e. radii contained within each edge).
    // This function relies on the fact we only get radii not contained within each edge if one of the radii
    // for an edge is zero, so we can shift the arc towards the zero radius corner.
    RoundedRect::Radii newRadii = innerBorder.radii();
    IntRect newRect = innerBorder.rect();

    float overshoot;
    float maxRadii;

    switch (side) {
    case BSTop:
        overshoot = newRadii.topLeft().width() + newRadii.topRight().width() - newRect.width();
        if (overshoot > 0) {
            ASSERT(!(newRadii.topLeft().width() && newRadii.topRight().width()));
            newRect.setWidth(newRect.width() + overshoot);
            if (!newRadii.topLeft().width())
                newRect.move(-overshoot, 0);
        }
        newRadii.setBottomLeft(IntSize(0, 0));
        newRadii.setBottomRight(IntSize(0, 0));
        maxRadii = max(newRadii.topLeft().height(), newRadii.topRight().height());
        if (maxRadii > newRect.height())
            newRect.setHeight(maxRadii);
        break;

    case BSBottom:
        overshoot = newRadii.bottomLeft().width() + newRadii.bottomRight().width() - newRect.width();
        if (overshoot > 0) {
            ASSERT(!(newRadii.bottomLeft().width() && newRadii.bottomRight().width()));
            newRect.setWidth(newRect.width() + overshoot);
            if (!newRadii.bottomLeft().width())
                newRect.move(-overshoot, 0);
        }
        newRadii.setTopLeft(IntSize(0, 0));
        newRadii.setTopRight(IntSize(0, 0));
        maxRadii = max(newRadii.bottomLeft().height(), newRadii.bottomRight().height());
        if (maxRadii > newRect.height()) {
            newRect.move(0, newRect.height() - maxRadii);
            newRect.setHeight(maxRadii);
        }
        break;

    case BSLeft:
        overshoot = newRadii.topLeft().height() + newRadii.bottomLeft().height() - newRect.height();
        if (overshoot > 0) {
            ASSERT(!(newRadii.topLeft().height() && newRadii.bottomLeft().height()));
            newRect.setHeight(newRect.height() + overshoot);
            if (!newRadii.topLeft().height())
                newRect.move(0, -overshoot);
        }
        newRadii.setTopRight(IntSize(0, 0));
        newRadii.setBottomRight(IntSize(0, 0));
        maxRadii = max(newRadii.topLeft().width(), newRadii.bottomLeft().width());
        if (maxRadii > newRect.width())
            newRect.setWidth(maxRadii);
        break;

    case BSRight:
        overshoot = newRadii.topRight().height() + newRadii.bottomRight().height() - newRect.height();
        if (overshoot > 0) {
            ASSERT(!(newRadii.topRight().height() && newRadii.bottomRight().height()));
            newRect.setHeight(newRect.height() + overshoot);
            if (!newRadii.topRight().height())
                newRect.move(0, -overshoot);
        }
        newRadii.setTopLeft(IntSize(0, 0));
        newRadii.setBottomLeft(IntSize(0, 0));
        maxRadii = max(newRadii.topRight().width(), newRadii.bottomRight().width());
        if (maxRadii > newRect.width()) {
            newRect.move(newRect.width() - maxRadii, 0);
            newRect.setWidth(maxRadii);
        }
        break;
    }

    return RoundedRect(newRect, newRadii);
}

void RenderBoxModelObject::clipBorderSideForComplexInnerPath(GraphicsContext* graphicsContext, const RoundedRect& outerBorder, const RoundedRect& innerBorder,
    BoxSide side, const class BorderEdge edges[])
{
    graphicsContext->clip(calculateSideRectIncludingInner(outerBorder, edges, side));
    RoundedRect adjustedInnerRect = calculateAdjustedInnerBorder(innerBorder, side);
    if (!adjustedInnerRect.isEmpty())
        graphicsContext->clipOutRoundedRect(adjustedInnerRect);
}

void RenderBoxModelObject::getBorderEdgeInfo(BorderEdge edges[], const RenderStyle* style, bool includeLogicalLeftEdge, bool includeLogicalRightEdge) const
{
    bool horizontal = style->isHorizontalWritingMode();

    edges[BSTop] = BorderEdge(style->borderTopWidth(),
        resolveColor(style, CSSPropertyBorderTopColor),
        style->borderTopStyle(),
        style->borderTopIsTransparent(),
        horizontal || includeLogicalLeftEdge);

    edges[BSRight] = BorderEdge(style->borderRightWidth(),
        resolveColor(style, CSSPropertyBorderRightColor),
        style->borderRightStyle(),
        style->borderRightIsTransparent(),
        !horizontal || includeLogicalRightEdge);

    edges[BSBottom] = BorderEdge(style->borderBottomWidth(),
        resolveColor(style, CSSPropertyBorderBottomColor),
        style->borderBottomStyle(),
        style->borderBottomIsTransparent(),
        horizontal || includeLogicalRightEdge);

    edges[BSLeft] = BorderEdge(style->borderLeftWidth(),
        resolveColor(style, CSSPropertyBorderLeftColor),
        style->borderLeftStyle(),
        style->borderLeftIsTransparent(),
        !horizontal || includeLogicalLeftEdge);
}

bool RenderBoxModelObject::borderObscuresBackgroundEdge(const FloatSize& contextScale) const
{
    BorderEdge edges[4];
    getBorderEdgeInfo(edges, style());

    for (int i = BSTop; i <= BSLeft; ++i) {
        const BorderEdge& currEdge = edges[i];
        // FIXME: for vertical text
        float axisScale = (i == BSTop || i == BSBottom) ? contextScale.height() : contextScale.width();
        if (!currEdge.obscuresBackgroundEdge(axisScale))
            return false;
    }

    return true;
}

bool RenderBoxModelObject::borderObscuresBackground() const
{
    if (!style()->hasBorder())
        return false;

    // Bail if we have any border-image for now. We could look at the image alpha to improve this.
    if (style()->borderImage().image())
        return false;

    BorderEdge edges[4];
    getBorderEdgeInfo(edges, style());

    for (int i = BSTop; i <= BSLeft; ++i) {
        const BorderEdge& currEdge = edges[i];
        if (!currEdge.obscuresBackground())
            return false;
    }

    return true;
}

bool RenderBoxModelObject::boxShadowShouldBeAppliedToBackground(BackgroundBleedAvoidance bleedAvoidance, InlineFlowBox* inlineFlowBox) const
{
    if (bleedAvoidance != BackgroundBleedNone)
        return false;

    if (style()->hasAppearance())
        return false;

    const ShadowList* shadowList = style()->boxShadow();
    if (!shadowList)
        return false;

    bool hasOneNormalBoxShadow = false;
    size_t shadowCount = shadowList->shadows().size();
    for (size_t i = 0; i < shadowCount; ++i) {
        const ShadowData& currentShadow = shadowList->shadows()[i];
        if (currentShadow.style() != Normal)
            continue;

        if (hasOneNormalBoxShadow)
            return false;
        hasOneNormalBoxShadow = true;

        if (currentShadow.spread())
            return false;
    }

    if (!hasOneNormalBoxShadow)
        return false;

    Color backgroundColor = resolveColor(CSSPropertyBackgroundColor);
    if (backgroundColor.hasAlpha())
        return false;

    const FillLayer* lastBackgroundLayer = style()->backgroundLayers();
    for (const FillLayer* next = lastBackgroundLayer->next(); next; next = lastBackgroundLayer->next())
        lastBackgroundLayer = next;

    if (lastBackgroundLayer->clip() != BorderFillBox)
        return false;

    if (lastBackgroundLayer->image() && style()->hasBorderRadius())
        return false;

    if (inlineFlowBox && !inlineFlowBox->boxShadowCanBeAppliedToBackground(*lastBackgroundLayer))
        return false;

    if (hasOverflowClip() && lastBackgroundLayer->attachment() == LocalBackgroundAttachment)
        return false;

    return true;
}

void RenderBoxModelObject::paintBoxShadow(const PaintInfo& info, const LayoutRect& paintRect, const RenderStyle* s, ShadowStyle shadowStyle, bool includeLogicalLeftEdge, bool includeLogicalRightEdge)
{
    // FIXME: Deal with border-image.  Would be great to use border-image as a mask.
    GraphicsContext* context = info.context;
    if (context->paintingDisabled() || !s->boxShadow())
        return;

    RoundedRect border = (shadowStyle == Inset) ? s->getRoundedInnerBorderFor(paintRect, includeLogicalLeftEdge, includeLogicalRightEdge)
        : s->getRoundedBorderFor(paintRect, includeLogicalLeftEdge, includeLogicalRightEdge);

    bool hasBorderRadius = s->hasBorderRadius();
    bool isHorizontal = s->isHorizontalWritingMode();
    bool hasOpaqueBackground = s->visitedDependentColor(CSSPropertyBackgroundColor).alpha() == 255;

    GraphicsContextStateSaver stateSaver(*context, false);

    const ShadowList* shadowList = s->boxShadow();
    for (size_t i = shadowList->shadows().size(); i--; ) {
        const ShadowData& shadow = shadowList->shadows()[i];
        if (shadow.style() != shadowStyle)
            continue;

        FloatSize shadowOffset(shadow.x(), shadow.y());
        float shadowBlur = shadow.blur();
        float shadowSpread = shadow.spread();

        if (shadowOffset.isZero() && !shadowBlur && !shadowSpread)
            continue;

        const Color& shadowColor = shadow.color();

        if (shadow.style() == Normal) {
            FloatRect fillRect = border.rect();
            fillRect.inflate(shadowSpread);
            if (fillRect.isEmpty())
                continue;

            FloatRect shadowRect(border.rect());
            shadowRect.inflate(shadowBlur + shadowSpread);
            shadowRect.move(shadowOffset);

            // Save the state and clip, if not already done.
            // The clip does not depend on any shadow-specific properties.
            if (!stateSaver.saved()) {
                stateSaver.save();
                if (hasBorderRadius) {
                    RoundedRect rectToClipOut = border;

                    // If the box is opaque, it is unnecessary to clip it out. However, doing so saves time
                    // when painting the shadow. On the other hand, it introduces subpixel gaps along the
                    // corners. Those are avoided by insetting the clipping path by one pixel.
                    if (hasOpaqueBackground)
                        rectToClipOut.inflateWithRadii(-1);

                    if (!rectToClipOut.isEmpty()) {
                        context->clipOutRoundedRect(rectToClipOut);
                    }
                } else {
                    // This IntRect is correct even with fractional shadows, because it is used for the rectangle
                    // of the box itself, which is always pixel-aligned.
                    IntRect rectToClipOut = border.rect();

                    // If the box is opaque, it is unnecessary to clip it out. However, doing so saves time
                    // when painting the shadow. On the other hand, it introduces subpixel gaps along the
                    // edges if they are not pixel-aligned. Those are avoided by insetting the clipping path
                    // by one pixel.
                    if (hasOpaqueBackground) {
                        // FIXME: The function to decide on the policy based on the transform should be a named function.
                        // FIXME: It's not clear if this check is right. What about integral scale factors?
                        AffineTransform transform = context->getCTM();
                        if (transform.a() != 1 || (transform.d() != 1 && transform.d() != -1) || transform.b() || transform.c())
                            rectToClipOut.inflate(-1);
                    }

                    if (!rectToClipOut.isEmpty()) {
                        context->clipOut(rectToClipOut);
                    }
                }
            }

            // Draw only the shadow.
            OwnPtr<DrawLooperBuilder> drawLooperBuilder = DrawLooperBuilder::create();
            drawLooperBuilder->addShadow(shadowOffset, shadowBlur, shadowColor,
                DrawLooperBuilder::ShadowRespectsTransforms, DrawLooperBuilder::ShadowIgnoresAlpha);
            context->setDrawLooper(drawLooperBuilder.release());

            if (hasBorderRadius) {
                RoundedRect influenceRect(pixelSnappedIntRect(LayoutRect(shadowRect)), border.radii());
                influenceRect.expandRadii(2 * shadowBlur + shadowSpread);
                if (allCornersClippedOut(influenceRect, info.rect))
                    context->fillRect(fillRect, Color::black);
                else {
                    // TODO: support non-integer shadows - crbug.com/334829
                    RoundedRect roundedFillRect = border;
                    roundedFillRect.inflate(shadowSpread);

                    roundedFillRect.expandRadii(shadowSpread);
                    if (!roundedFillRect.isRenderable())
                        roundedFillRect.adjustRadii();
                    context->fillRoundedRect(roundedFillRect, Color::black);
                }
            } else {
                context->fillRect(fillRect, Color::black);
            }
        } else {
            // The inset shadow case.
            GraphicsContext::Edges clippedEdges = GraphicsContext::NoEdge;
            if (!includeLogicalLeftEdge) {
                if (isHorizontal)
                    clippedEdges |= GraphicsContext::LeftEdge;
                else
                    clippedEdges |= GraphicsContext::TopEdge;
            }
            if (!includeLogicalRightEdge) {
                if (isHorizontal)
                    clippedEdges |= GraphicsContext::RightEdge;
                else
                    clippedEdges |= GraphicsContext::BottomEdge;
            }
            // TODO: support non-integer shadows - crbug.com/334828
            context->drawInnerShadow(border, shadowColor, flooredIntSize(shadowOffset), shadowBlur, shadowSpread, clippedEdges);
        }
    }
}

LayoutUnit RenderBoxModelObject::containingBlockLogicalWidthForContent() const
{
    return containingBlock()->availableLogicalWidth();
}

RenderBoxModelObject* RenderBoxModelObject::continuation() const
{
    if (!continuationMap)
        return 0;
    return continuationMap->get(this);
}

void RenderBoxModelObject::setContinuation(RenderBoxModelObject* continuation)
{
    if (continuation) {
        if (!continuationMap)
            continuationMap = new ContinuationMap;
        continuationMap->set(this, continuation);
    } else {
        if (continuationMap)
            continuationMap->remove(this);
    }
}

void RenderBoxModelObject::computeLayerHitTestRects(LayerHitTestRects& rects) const
{
    RenderLayerModelObject::computeLayerHitTestRects(rects);

    // If there is a continuation then we need to consult it here, since this is
    // the root of the tree walk and it wouldn't otherwise get picked up.
    // Continuations should always be siblings in the tree, so any others should
    // get picked up already by the tree walk.
    if (continuation())
        continuation()->computeLayerHitTestRects(rects);
}

RenderTextFragment* RenderBoxModelObject::firstLetterRemainingText() const
{
    if (!firstLetterRemainingTextMap)
        return 0;
    return firstLetterRemainingTextMap->get(this);
}

void RenderBoxModelObject::setFirstLetterRemainingText(RenderTextFragment* remainingText)
{
    if (remainingText) {
        if (!firstLetterRemainingTextMap)
            firstLetterRemainingTextMap = new FirstLetterRemainingTextMap;
        firstLetterRemainingTextMap->set(this, remainingText);
    } else if (firstLetterRemainingTextMap)
        firstLetterRemainingTextMap->remove(this);
}

LayoutRect RenderBoxModelObject::localCaretRectForEmptyElement(LayoutUnit width, LayoutUnit textIndentOffset)
{
    ASSERT(!firstChild());

    // FIXME: This does not take into account either :first-line or :first-letter
    // However, as soon as some content is entered, the line boxes will be
    // constructed and this kludge is not called any more. So only the caret size
    // of an empty :first-line'd block is wrong. I think we can live with that.
    RenderStyle* currentStyle = firstLineStyle();
    LayoutUnit height = lineHeight(true, currentStyle->isHorizontalWritingMode() ? HorizontalLine : VerticalLine,  PositionOfInteriorLineBoxes);

    enum CaretAlignment { alignLeft, alignRight, alignCenter };

    CaretAlignment alignment = alignLeft;

    switch (currentStyle->textAlign()) {
    case LEFT:
    case WEBKIT_LEFT:
        break;
    case CENTER:
    case WEBKIT_CENTER:
        alignment = alignCenter;
        break;
    case RIGHT:
    case WEBKIT_RIGHT:
        alignment = alignRight;
        break;
    case JUSTIFY:
    case TASTART:
        if (!currentStyle->isLeftToRightDirection())
            alignment = alignRight;
        break;
    case TAEND:
        if (currentStyle->isLeftToRightDirection())
            alignment = alignRight;
        break;
    }

    LayoutUnit x = borderLeft() + paddingLeft();
    LayoutUnit maxX = width - borderRight() - paddingRight();

    switch (alignment) {
    case alignLeft:
        if (currentStyle->isLeftToRightDirection())
            x += textIndentOffset;
        break;
    case alignCenter:
        x = (x + maxX) / 2;
        if (currentStyle->isLeftToRightDirection())
            x += textIndentOffset / 2;
        else
            x -= textIndentOffset / 2;
        break;
    case alignRight:
        x = maxX - caretWidth;
        if (!currentStyle->isLeftToRightDirection())
            x -= textIndentOffset;
        break;
    }
    x = min(x, max<LayoutUnit>(maxX - caretWidth, 0));

    LayoutUnit y = paddingTop() + borderTop();

    return currentStyle->isHorizontalWritingMode() ? LayoutRect(x, y, caretWidth, height) : LayoutRect(y, x, height, caretWidth);
}

bool RenderBoxModelObject::shouldAntialiasLines(GraphicsContext* context)
{
    // FIXME: We may want to not antialias when scaled by an integral value,
    // and we may want to antialias when translated by a non-integral value.
    return !context->getCTM().isIdentityOrTranslationOrFlipped();
}

void RenderBoxModelObject::mapAbsoluteToLocalPoint(MapCoordinatesFlags mode, TransformState& transformState) const
{
    // We don't expect to be called during layout.
    ASSERT(!view() || !view()->layoutStateEnabled());

    RenderObject* o = container();
    if (!o)
        return;

    // The point inside a box that's inside a region has its coordinates relative to the region,
    // not the FlowThread that is its container in the RenderObject tree.
    if (o->isRenderFlowThread() && isRenderBlock()) {
        // FIXME: switch to Box instead of Block when we'll have range information for boxes as well, not just for blocks.
        RenderRegion* startRegion;
        RenderRegion* ignoredEndRegion;
        toRenderFlowThread(o)->getRegionRangeForBox(toRenderBlock(this), startRegion, ignoredEndRegion);
        // If there is no region to use the FlowThread, then there's no region range for the content in that FlowThread.
        // An API like elementFromPoint might crash without this check.
        if (startRegion)
            o = startRegion;
    }

    o->mapAbsoluteToLocalPoint(mode, transformState);

    LayoutSize containerOffset = offsetFromContainer(o, LayoutPoint());

    if (!style()->hasOutOfFlowPosition() && o->hasColumns()) {
        RenderBlock* block = toRenderBlock(o);
        LayoutPoint point(roundedLayoutPoint(transformState.mappedPoint()));
        point -= containerOffset;
        block->adjustForColumnRect(containerOffset, point);
    }

    bool preserve3D = mode & UseTransforms && (o->style()->preserves3D() || style()->preserves3D());
    if (mode & UseTransforms && shouldUseTransformFromContainer(o)) {
        TransformationMatrix t;
        getTransformFromContainer(o, containerOffset, t);
        transformState.applyTransform(t, preserve3D ? TransformState::AccumulateTransform : TransformState::FlattenTransform);
    } else
        transformState.move(containerOffset.width(), containerOffset.height(), preserve3D ? TransformState::AccumulateTransform : TransformState::FlattenTransform);
}

const RenderObject* RenderBoxModelObject::pushMappingToContainer(const RenderLayerModelObject* ancestorToStopAt, RenderGeometryMap& geometryMap) const
{
    ASSERT(ancestorToStopAt != this);

    bool ancestorSkipped;
    RenderObject* container = this->container(ancestorToStopAt, &ancestorSkipped);
    if (!container)
        return 0;

    bool isInline = isRenderInline();
    bool isFixedPos = !isInline && style()->position() == FixedPosition;
    bool hasTransform = !isInline && hasLayer() && layer()->transform();

    LayoutSize adjustmentForSkippedAncestor;
    if (ancestorSkipped) {
        // There can't be a transform between repaintContainer and o, because transforms create containers, so it should be safe
        // to just subtract the delta between the ancestor and o.
        adjustmentForSkippedAncestor = -ancestorToStopAt->offsetFromAncestorContainer(container);
    }

    bool offsetDependsOnPoint = false;
    LayoutSize containerOffset = offsetFromContainer(container, LayoutPoint(), &offsetDependsOnPoint);

    bool preserve3D = container->style()->preserves3D() || style()->preserves3D();
    if (shouldUseTransformFromContainer(container)) {
        TransformationMatrix t;
        getTransformFromContainer(container, containerOffset, t);
        t.translateRight(adjustmentForSkippedAncestor.width().toFloat(), adjustmentForSkippedAncestor.height().toFloat());
        geometryMap.push(this, t, preserve3D, offsetDependsOnPoint, isFixedPos, hasTransform);
    } else {
        containerOffset += adjustmentForSkippedAncestor;
        geometryMap.push(this, containerOffset, preserve3D, offsetDependsOnPoint, isFixedPos, hasTransform);
    }

    return ancestorSkipped ? ancestorToStopAt : container;
}

void RenderBoxModelObject::moveChildTo(RenderBoxModelObject* toBoxModelObject, RenderObject* child, RenderObject* beforeChild, bool fullRemoveInsert)
{
    // We assume that callers have cleared their positioned objects list for child moves (!fullRemoveInsert) so the
    // positioned renderer maps don't become stale. It would be too slow to do the map lookup on each call.
    ASSERT(!fullRemoveInsert || !isRenderBlock() || !toRenderBlock(this)->hasPositionedObjects());

    ASSERT(this == child->parent());
    ASSERT(!beforeChild || toBoxModelObject == beforeChild->parent());
    if (fullRemoveInsert && (toBoxModelObject->isRenderBlock() || toBoxModelObject->isRenderInline())) {
        // Takes care of adding the new child correctly if toBlock and fromBlock
        // have different kind of children (block vs inline).
        toBoxModelObject->addChild(virtualChildren()->removeChildNode(this, child), beforeChild);
    } else
        toBoxModelObject->virtualChildren()->insertChildNode(toBoxModelObject, virtualChildren()->removeChildNode(this, child, fullRemoveInsert), beforeChild, fullRemoveInsert);
}

void RenderBoxModelObject::moveChildrenTo(RenderBoxModelObject* toBoxModelObject, RenderObject* startChild, RenderObject* endChild, RenderObject* beforeChild, bool fullRemoveInsert)
{
    // This condition is rarely hit since this function is usually called on
    // anonymous blocks which can no longer carry positioned objects (see r120761)
    // or when fullRemoveInsert is false.
    if (fullRemoveInsert && isRenderBlock()) {
        RenderBlock* block = toRenderBlock(this);
        block->removePositionedObjects(0);
        if (block->isRenderBlockFlow())
            toRenderBlockFlow(block)->removeFloatingObjects();
    }

    ASSERT(!beforeChild || toBoxModelObject == beforeChild->parent());
    for (RenderObject* child = startChild; child && child != endChild; ) {
        // Save our next sibling as moveChildTo will clear it.
        RenderObject* nextSibling = child->nextSibling();
        moveChildTo(toBoxModelObject, child, beforeChild, fullRemoveInsert);
        child = nextSibling;
    }
}

} // namespace WebCore