Source/WebCore/rendering/RenderRegion.cpp

/*
 * Copyright (C) 2011 Adobe Systems Incorporated. All rights reserved.
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 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
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 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER "AS IS" AND ANY
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 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
 * OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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#include "config.h"
#include "RenderRegion.h"

#include "FlowThreadController.h"
#include "GraphicsContext.h"
#include "HitTestResult.h"
#include "IntRect.h"
#include "PaintInfo.h"
#include "RenderBoxRegionInfo.h"
#include "RenderNamedFlowThread.h"
#include "RenderView.h"
#include "StyleResolver.h"

namespace WebCore {

RenderRegion::RenderRegion(Node* node, RenderFlowThread* flowThread)
    : RenderReplaced(node, IntSize())
    , m_flowThread(flowThread)
    , m_parentNamedFlowThread(0)
    , m_isValid(false)
    , m_hasCustomRegionStyle(false)
    , m_regionState(RegionUndefined)
    , m_dispatchRegionLayoutUpdateEvent(false)
{
}

LayoutUnit RenderRegion::logicalWidthForFlowThreadContent() const
{
    return m_flowThread->isHorizontalWritingMode() ? contentWidth() : contentHeight();
}

LayoutUnit RenderRegion::logicalHeightForFlowThreadContent() const
{
    return m_flowThread->isHorizontalWritingMode() ? contentHeight() : contentWidth();
}

LayoutRect RenderRegion::regionOverflowRect() const
{
    // FIXME: Would like to just use hasOverflowClip() but we aren't a block yet. When RenderRegion is eliminated and
    // folded into RenderBlock, switch to hasOverflowClip().
    bool clipX = style()->overflowX() != OVISIBLE;
    bool clipY = style()->overflowY() != OVISIBLE;
    if ((clipX && clipY) || !isValid() || !m_flowThread)
        return regionRect();

    LayoutRect flowThreadOverflow = m_flowThread->visualOverflowRect();

    // Only clip along the flow thread axis.
    LayoutUnit outlineSize = maximalOutlineSize(PaintPhaseOutline);
    LayoutRect clipRect;
    if (m_flowThread->isHorizontalWritingMode()) {
        LayoutUnit minY = isFirstRegion() ? (flowThreadOverflow.y() - outlineSize) : regionRect().y();
        LayoutUnit maxY = isLastRegion() ? max(regionRect().maxY(), flowThreadOverflow.maxY()) + outlineSize : regionRect().maxY();
        LayoutUnit minX = clipX ? regionRect().x() : (flowThreadOverflow.x() - outlineSize);
        LayoutUnit maxX = clipX ? regionRect().maxX() : (flowThreadOverflow.maxX() + outlineSize);
        clipRect = LayoutRect(minX, minY, maxX - minX, maxY - minY);
    } else {
        LayoutUnit minX = isFirstRegion() ? (flowThreadOverflow.x() - outlineSize) : regionRect().x();
        LayoutUnit maxX = isLastRegion() ? max(regionRect().maxX(), flowThreadOverflow.maxX()) + outlineSize : regionRect().maxX();
        LayoutUnit minY = clipY ? regionRect().y() : (flowThreadOverflow.y() - outlineSize);
        LayoutUnit maxY = clipY ? regionRect().maxY() : (flowThreadOverflow.maxY() + outlineSize);
        clipRect = LayoutRect(minX, minY, maxX - minX, maxY - minY);
    }

    return clipRect;
}

bool RenderRegion::isFirstRegion() const
{
    ASSERT(isValid() && m_flowThread);
    return m_flowThread->firstRegion() == this;
}

bool RenderRegion::isLastRegion() const
{
    ASSERT(isValid() && m_flowThread);
    return m_flowThread->lastRegion() == this;
}

void RenderRegion::paintReplaced(PaintInfo& paintInfo, const LayoutPoint& paintOffset)
{
    // Delegate painting of content in region to RenderFlowThread.
    if (!m_flowThread || !isValid())
        return;

    setRegionObjectsRegionStyle();
    m_flowThread->paintIntoRegion(paintInfo, this, LayoutPoint(paintOffset.x() + borderLeft() + paddingLeft(), paintOffset.y() + borderTop() + paddingTop()));
    restoreRegionObjectsOriginalStyle();
}

// Hit Testing
bool RenderRegion::nodeAtPoint(const HitTestRequest& request, HitTestResult& result, const LayoutPoint& pointInContainer, const LayoutPoint& accumulatedOffset, HitTestAction action)
{
    if (!isValid())
        return false;

    LayoutPoint adjustedLocation = accumulatedOffset + location();

    // Check our bounds next. For this purpose always assume that we can only be hit in the
    // foreground phase (which is true for replaced elements like images).
    LayoutRect boundsRect = borderBoxRectInRegion(result.region());
    boundsRect.moveBy(adjustedLocation);
    if (visibleToHitTesting() && action == HitTestForeground && boundsRect.intersects(result.rectForPoint(pointInContainer))) {
        // Check the contents of the RenderFlowThread.
        if (m_flowThread && m_flowThread->hitTestRegion(this, request, result, pointInContainer, LayoutPoint(adjustedLocation.x() + borderLeft() + paddingLeft(), adjustedLocation.y() + borderTop() + paddingTop())))
            return true;
        updateHitTestResult(result, pointInContainer - toLayoutSize(adjustedLocation));
        if (!result.addNodeToRectBasedTestResult(node(), pointInContainer, boundsRect))
            return true;
    }

    return false;
}

void RenderRegion::styleDidChange(StyleDifference diff, const RenderStyle* oldStyle)
{
    RenderReplaced::styleDidChange(diff, oldStyle);
    bool customRegionStyle = false;
    if (node()) {
        Element* regionElement = static_cast<Element*>(node());
        customRegionStyle = view()->document()->styleResolver()->checkRegionStyle(regionElement);
    }
    setHasCustomRegionStyle(customRegionStyle);
    flowThread()->checkRegionsWithStyling();
}

void RenderRegion::layout()
{
    RenderReplaced::layout();
    if (m_flowThread && isValid()) {
        LayoutRect oldRegionRect(regionRect());
        if (!isHorizontalWritingMode())
            oldRegionRect = oldRegionRect.transposedRect();
        if (oldRegionRect.width() != logicalWidthForFlowThreadContent() || oldRegionRect.height() != logicalHeightForFlowThreadContent())
            m_flowThread->invalidateRegions();
    }

    // FIXME: We need to find a way to set up overflow properly. Our flow thread hasn't gotten a layout
    // yet, so we can't look to it for correct information. It's possible we could wait until after the RenderFlowThread
    // gets a layout, and then try to propagate overflow information back to the region, and then mark for a second layout.
    // That second layout would then be able to use the information from the RenderFlowThread to set up overflow.
    //
    // The big problem though is that overflow needs to be region-specific. We can't simply use the RenderFlowThread's global
    // overflow values, since then we'd always think any narrow region had huge overflow (all the way to the width of the
    // RenderFlowThread itself).
    //
    // We'll need to expand RenderBoxRegionInfo to also hold left and right overflow values.
}

void RenderRegion::attachRegion()
{
    if (!m_flowThread)
        return;

    // By now the flow thread should already be added to the rendering tree,
    // so we go up the rendering parents and check that this region is not part of the same
    // flow that it actually needs to display. It would create a circular reference.
    RenderObject* parentObject = parent();
    m_parentNamedFlowThread = 0;
    for ( ; parentObject; parentObject = parentObject->parent()) {
        if (parentObject->isRenderNamedFlowThread()) {
            m_parentNamedFlowThread = toRenderNamedFlowThread(parentObject);
            // Do not take into account a region that links a flow with itself. The dependency
            // cannot change, so it is not worth adding it to the list.
            if (m_flowThread == m_parentNamedFlowThread) {
                m_flowThread = 0;
                return;
            }
            break;
        }
    }

    m_flowThread->addRegionToThread(this);
}

void RenderRegion::detachRegion()
{
    if (m_flowThread)
        m_flowThread->removeRegionFromThread(this);
}

RenderBoxRegionInfo* RenderRegion::renderBoxRegionInfo(const RenderBox* box) const
{
    if (!m_isValid || !m_flowThread)
        return 0;
    return m_renderBoxRegionInfo.get(box);
}

RenderBoxRegionInfo* RenderRegion::setRenderBoxRegionInfo(const RenderBox* box, LayoutUnit logicalLeftInset, LayoutUnit logicalRightInset,
    bool containingBlockChainIsInset)
{
    ASSERT(m_isValid && m_flowThread);
    if (!m_isValid || !m_flowThread)
        return 0;

    OwnPtr<RenderBoxRegionInfo>& boxInfo = m_renderBoxRegionInfo.add(box, nullptr).iterator->second;
    if (boxInfo)
        *boxInfo = RenderBoxRegionInfo(logicalLeftInset, logicalRightInset, containingBlockChainIsInset);
    else
        boxInfo = adoptPtr(new RenderBoxRegionInfo(logicalLeftInset, logicalRightInset, containingBlockChainIsInset));

    return boxInfo.get();
}

PassOwnPtr<RenderBoxRegionInfo> RenderRegion::takeRenderBoxRegionInfo(const RenderBox* box)
{
    return m_renderBoxRegionInfo.take(box);
}

void RenderRegion::removeRenderBoxRegionInfo(const RenderBox* box)
{
    m_renderBoxRegionInfo.remove(box);
}

void RenderRegion::deleteAllRenderBoxRegionInfo()
{
    m_renderBoxRegionInfo.clear();
}

LayoutUnit RenderRegion::offsetFromLogicalTopOfFirstPage() const
{
    if (!m_isValid || !m_flowThread)
        return 0;
    if (m_flowThread->isHorizontalWritingMode())
        return regionRect().y();
    return regionRect().x();
}

void RenderRegion::setRegionObjectsRegionStyle()
{
    if (!hasCustomRegionStyle())
        return;

    // Start from content nodes and recursively compute the style in region for the render objects below.
    // If the style in region was already computed, used that style instead of computing a new one.
    RenderNamedFlowThread* namedFlow = view()->flowThreadController()->ensureRenderFlowThreadWithName(style()->regionThread());
    const NamedFlowContentNodes& contentNodes = namedFlow->contentNodes();

    for (NamedFlowContentNodes::const_iterator iter = contentNodes.begin(), end = contentNodes.end(); iter != end; ++iter) {
        const Node* node = *iter;
        // The list of content nodes contains also the nodes with display:none.
        if (!node->renderer())
            continue;

        RenderObject* object = node->renderer();
        // If the content node does not flow any of its children in this region,
        // we do not compute any style for them in this region.
        if (!flowThread()->objectInFlowRegion(object, this))
            continue;

        // If the object has style in region, use that instead of computing a new one.
        RenderObjectRegionStyleMap::iterator it = m_renderObjectRegionStyle.find(object);
        RefPtr<RenderStyle> objectStyleInRegion;
        bool objectRegionStyleCached = false;
        if (it != m_renderObjectRegionStyle.end()) {
            objectStyleInRegion = it->second.style;
            ASSERT(it->second.cached);
            objectRegionStyleCached = true;
        } else
            objectStyleInRegion = computeStyleInRegion(object);

        setObjectStyleInRegion(object, objectStyleInRegion, objectRegionStyleCached);

        computeChildrenStyleInRegion(object);
    }
}

void RenderRegion::restoreRegionObjectsOriginalStyle()
{
    if (!hasCustomRegionStyle())
        return;

    RenderObjectRegionStyleMap temp;
    for (RenderObjectRegionStyleMap::iterator iter = m_renderObjectRegionStyle.begin(), end = m_renderObjectRegionStyle.end(); iter != end; ++iter) {
        RenderObject* object = const_cast<RenderObject*>(iter->first);
        RefPtr<RenderStyle> objectRegionStyle = object->style();
        RefPtr<RenderStyle> objectOriginalStyle = iter->second.style;
        object->setStyleInternal(objectOriginalStyle);

        bool shouldCacheRegionStyle = iter->second.cached;
        if (!shouldCacheRegionStyle) {
            // Check whether we should cache the computed style in region.
            unsigned changedContextSensitiveProperties = ContextSensitivePropertyNone;
            StyleDifference styleDiff = objectOriginalStyle->diff(objectRegionStyle.get(), changedContextSensitiveProperties);
            if (styleDiff < StyleDifferenceLayoutPositionedMovementOnly)
                shouldCacheRegionStyle = true;
        }
        if (shouldCacheRegionStyle) {
            ObjectRegionStyleInfo styleInfo;
            styleInfo.style = objectRegionStyle;
            styleInfo.cached = true;
            temp.set(object, styleInfo);
        }
    }

    m_renderObjectRegionStyle.swap(temp);
}

PassRefPtr<RenderStyle> RenderRegion::computeStyleInRegion(const RenderObject* object)
{
    ASSERT(object);
    ASSERT(object->view());
    ASSERT(object->view()->document());
    ASSERT(!object->isAnonymous());
    ASSERT(object->node() && object->node()->isElementNode());

    Element* element = toElement(object->node());
    RefPtr<RenderStyle> renderObjectRegionStyle = object->view()->document()->styleResolver()->styleForElement(element, 0, DisallowStyleSharing, MatchAllRules, this);

    return renderObjectRegionStyle.release();
}
 
void RenderRegion::computeChildrenStyleInRegion(const RenderObject* object)
{
    for (RenderObject* child = object->firstChild(); child; child = child->nextSibling()) {

        RenderObjectRegionStyleMap::iterator it = m_renderObjectRegionStyle.find(child);

        RefPtr<RenderStyle> childStyleInRegion;
        bool objectRegionStyleCached = false;
        if (it != m_renderObjectRegionStyle.end()) {
            childStyleInRegion = it->second.style;
            objectRegionStyleCached = true;
        } else {
            if (child->isAnonymous())
                childStyleInRegion = RenderStyle::createAnonymousStyleWithDisplay(object->style(), child->style()->display());
            else if (child->isText())
                childStyleInRegion = RenderStyle::clone(object->style());
            else
                childStyleInRegion = computeStyleInRegion(child);
        }

        setObjectStyleInRegion(child, childStyleInRegion, objectRegionStyleCached);

        computeChildrenStyleInRegion(child);
    }
}
 
void RenderRegion::setObjectStyleInRegion(RenderObject* object, PassRefPtr<RenderStyle> styleInRegion, bool objectRegionStyleCached)
{
    RefPtr<RenderStyle> objectOriginalStyle = object->style();
    object->setStyleInternal(styleInRegion);

    if (object->isBoxModelObject() && !object->hasBoxDecorations()) {
        bool hasBoxDecorations = object->isTableCell()
        || object->style()->hasBackground()
        || object->style()->hasBorder()
        || object->style()->hasAppearance()
        || object->style()->boxShadow();
        object->setHasBoxDecorations(hasBoxDecorations);
    }

    ObjectRegionStyleInfo styleInfo;
    styleInfo.style = objectOriginalStyle;
    styleInfo.cached = objectRegionStyleCached;
    m_renderObjectRegionStyle.set(object, styleInfo);
}
 
void RenderRegion::clearObjectStyleInRegion(const RenderObject* object)
{
    ASSERT(object);
    m_renderObjectRegionStyle.remove(object);

    // Clear the style for the children of this object.
    for (RenderObject* child = object->firstChild(); child; child = child->nextSibling())
        clearObjectStyleInRegion(child);
}

} // namespace WebCore