root/Source/core/rendering/RenderRubyRun.cpp

DEFINITIONS

1. hasRubyText
2. hasRubyBase
3. isEmpty
4. rubyText
5. rubyBase
6. rubyBaseSafe
7. firstLineBlock
8. updateFirstLetter
9. isChildAllowed
10. addChild
11. removeChild
12. createRubyBase
13. staticCreateRubyRun
14. layoutSpecialExcludedChild
15. layout
16. getOverhang

/*
 * Copyright (C) 2009 Google Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 *     * Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above
 * copyright notice, this list of conditions and the following disclaimer
 * in the documentation and/or other materials provided with the
 * distribution.
 *     * Neither the name of Google Inc. nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "config.h"

#include "core/rendering/RenderRubyRun.h"

#include "core/rendering/LayoutRectRecorder.h"
#include "core/rendering/RenderRubyBase.h"
#include "core/rendering/RenderRubyText.h"
#include "core/rendering/RenderText.h"

using namespace std;

namespace WebCore {

RenderRubyRun::RenderRubyRun()
    : RenderBlockFlow(0)
{
    setReplaced(true);
    setInline(true);
}

RenderRubyRun::~RenderRubyRun()
{
}

bool RenderRubyRun::hasRubyText() const
{
    // The only place where a ruby text can be is in the first position
    // Note: As anonymous blocks, ruby runs do not have ':before' or ':after' content themselves.
    return firstChild() && firstChild()->isRubyText();
}

bool RenderRubyRun::hasRubyBase() const
{
    // The only place where a ruby base can be is in the last position
    // Note: As anonymous blocks, ruby runs do not have ':before' or ':after' content themselves.
    return lastChild() && lastChild()->isRubyBase();
}

bool RenderRubyRun::isEmpty() const
{
    return !hasRubyText() && !hasRubyBase();
}

RenderRubyText* RenderRubyRun::rubyText() const
{
    RenderObject* child = firstChild();
    // If in future it becomes necessary to support floating or positioned ruby text,
    // layout will have to be changed to handle them properly.
    ASSERT(!child || !child->isRubyText() || !child->isFloatingOrOutOfFlowPositioned());
    return child && child->isRubyText() ? static_cast<RenderRubyText*>(child) : 0;
}

RenderRubyBase* RenderRubyRun::rubyBase() const
{
    RenderObject* child = lastChild();
    return child && child->isRubyBase() ? static_cast<RenderRubyBase*>(child) : 0;
}

RenderRubyBase* RenderRubyRun::rubyBaseSafe()
{
    RenderRubyBase* base = rubyBase();
    if (!base) {
        base = createRubyBase();
        RenderBlockFlow::addChild(base);
    }
    return base;
}

RenderBlock* RenderRubyRun::firstLineBlock() const
{
    return 0;
}

void RenderRubyRun::updateFirstLetter()
{
}

bool RenderRubyRun::isChildAllowed(RenderObject* child, RenderStyle*) const
{
    return child->isRubyText() || child->isInline();
}

void RenderRubyRun::addChild(RenderObject* child, RenderObject* beforeChild)
{
    ASSERT(child);

    if (child->isRubyText()) {
        if (!beforeChild) {
            // RenderRuby has already ascertained that we can add the child here.
            ASSERT(!hasRubyText());
            // prepend ruby texts as first child
            RenderBlockFlow::addChild(child, firstChild());
        }  else if (beforeChild->isRubyText()) {
            // New text is inserted just before another.
            // In this case the new text takes the place of the old one, and
            // the old text goes into a new run that is inserted as next sibling.
            ASSERT(beforeChild->parent() == this);
            RenderObject* ruby = parent();
            ASSERT(ruby->isRuby());
            RenderBlock* newRun = staticCreateRubyRun(ruby);
            ruby->addChild(newRun, nextSibling());
            // Add the new ruby text and move the old one to the new run
            // Note: Doing it in this order and not using RenderRubyRun's methods,
            // in order to avoid automatic removal of the ruby run in case there is no
            // other child besides the old ruby text.
            RenderBlockFlow::addChild(child, beforeChild);
            RenderBlockFlow::removeChild(beforeChild);
            newRun->addChild(beforeChild);
        } else if (hasRubyBase()) {
            // Insertion before a ruby base object.
            // In this case we need insert a new run before the current one and split the base.
            RenderObject* ruby = parent();
            RenderRubyRun* newRun = staticCreateRubyRun(ruby);
            ruby->addChild(newRun, this);
            newRun->addChild(child);
            rubyBaseSafe()->moveChildren(newRun->rubyBaseSafe(), beforeChild);
        }
    } else {
        // child is not a text -> insert it into the base
        // (append it instead if beforeChild is the ruby text)
        if (beforeChild && beforeChild->isRubyText())
            beforeChild = 0;
        rubyBaseSafe()->addChild(child, beforeChild);
    }
}

void RenderRubyRun::removeChild(RenderObject* child)
{
    // If the child is a ruby text, then merge the ruby base with the base of
    // the right sibling run, if possible.
    if (!beingDestroyed() && !documentBeingDestroyed() && child->isRubyText()) {
        RenderRubyBase* base = rubyBase();
        RenderObject* rightNeighbour = nextSibling();
        if (base && rightNeighbour && rightNeighbour->isRubyRun()) {
            // Ruby run without a base can happen only at the first run.
            RenderRubyRun* rightRun = toRenderRubyRun(rightNeighbour);
            if (rightRun->hasRubyBase()) {
                RenderRubyBase* rightBase = rightRun->rubyBaseSafe();
                // Collect all children in a single base, then swap the bases.
                rightBase->moveChildren(base);
                moveChildTo(rightRun, base);
                rightRun->moveChildTo(this, rightBase);
                // The now empty ruby base will be removed below.
                ASSERT(!rubyBase()->firstChild());
            }
        }
    }

    RenderBlockFlow::removeChild(child);

    if (!beingDestroyed() && !documentBeingDestroyed()) {
        // Check if our base (if any) is now empty. If so, destroy it.
        RenderBlock* base = rubyBase();
        if (base && !base->firstChild()) {
            RenderBlockFlow::removeChild(base);
            base->deleteLineBoxTree();
            base->destroy();
        }

        // If any of the above leaves the run empty, destroy it as well.
        if (isEmpty()) {
            parent()->removeChild(this);
            deleteLineBoxTree();
            destroy();
        }
    }
}

RenderRubyBase* RenderRubyRun::createRubyBase() const
{
    RenderRubyBase* renderer = RenderRubyBase::createAnonymous(&document());
    RefPtr<RenderStyle> newStyle = RenderStyle::createAnonymousStyleWithDisplay(style(), BLOCK);
    newStyle->setTextAlign(CENTER); // FIXME: use WEBKIT_CENTER?
    renderer->setStyle(newStyle.release());
    return renderer;
}

RenderRubyRun* RenderRubyRun::staticCreateRubyRun(const RenderObject* parentRuby)
{
    ASSERT(parentRuby && parentRuby->isRuby());
    RenderRubyRun* rr = new RenderRubyRun();
    rr->setDocumentForAnonymous(&parentRuby->document());
    RefPtr<RenderStyle> newStyle = RenderStyle::createAnonymousStyleWithDisplay(parentRuby->style(), INLINE_BLOCK);
    rr->setStyle(newStyle.release());
    return rr;
}

RenderObject* RenderRubyRun::layoutSpecialExcludedChild(bool relayoutChildren, SubtreeLayoutScope& layoutScope)
{
    // Don't bother positioning the RenderRubyRun yet.
    RenderRubyText* rt = rubyText();
    if (!rt)
        return 0;
    if (relayoutChildren)
        layoutScope.setChildNeedsLayout(rt);
    rt->layoutIfNeeded();
    return rt;
}

void RenderRubyRun::layout()
{
    LayoutRectRecorder recorder(*this);
    RenderBlockFlow::layout();

    RenderRubyText* rt = rubyText();
    if (!rt)
        return;

    rt->setLogicalLeft(0);

    // Place the RenderRubyText such that its bottom is flush with the lineTop of the first line of the RenderRubyBase.
    LayoutUnit lastLineRubyTextBottom = rt->logicalHeight();
    LayoutUnit firstLineRubyTextTop = 0;
    RootInlineBox* rootBox = rt->lastRootBox();
    if (rootBox) {
        // In order to align, we have to ignore negative leading.
        firstLineRubyTextTop = rt->firstRootBox()->logicalTopLayoutOverflow();
        lastLineRubyTextBottom = rootBox->logicalBottomLayoutOverflow();
    }

    if (style()->isFlippedLinesWritingMode() == (style()->rubyPosition() == RubyPositionAfter)) {
        LayoutUnit firstLineTop = 0;
        if (RenderRubyBase* rb = rubyBase()) {
            RootInlineBox* rootBox = rb->firstRootBox();
            if (rootBox)
                firstLineTop = rootBox->logicalTopLayoutOverflow();
            firstLineTop += rb->logicalTop();
        }

        rt->setLogicalTop(-lastLineRubyTextBottom + firstLineTop);
    } else {
        LayoutUnit lastLineBottom = logicalHeight();
        if (RenderRubyBase* rb = rubyBase()) {
            RootInlineBox* rootBox = rb->lastRootBox();
            if (rootBox)
                lastLineBottom = rootBox->logicalBottomLayoutOverflow();
            lastLineBottom += rb->logicalTop();
        }

        rt->setLogicalTop(-firstLineRubyTextTop + lastLineBottom);
    }

    // Update our overflow to account for the new RenderRubyText position.
    computeOverflow(clientLogicalBottom());
}

void RenderRubyRun::getOverhang(bool firstLine, RenderObject* startRenderer, RenderObject* endRenderer, int& startOverhang, int& endOverhang) const
{
    ASSERT(!needsLayout());

    startOverhang = 0;
    endOverhang = 0;

    RenderRubyBase* rubyBase = this->rubyBase();
    RenderRubyText* rubyText = this->rubyText();

    if (!rubyBase || !rubyText)
        return;

    if (!rubyBase->firstRootBox())
        return;

    int logicalWidth = this->logicalWidth();
    int logicalLeftOverhang = numeric_limits<int>::max();
    int logicalRightOverhang = numeric_limits<int>::max();
    for (RootInlineBox* rootInlineBox = rubyBase->firstRootBox(); rootInlineBox; rootInlineBox = rootInlineBox->nextRootBox()) {
        logicalLeftOverhang = min<int>(logicalLeftOverhang, rootInlineBox->logicalLeft());
        logicalRightOverhang = min<int>(logicalRightOverhang, logicalWidth - rootInlineBox->logicalRight());
    }

    startOverhang = style()->isLeftToRightDirection() ? logicalLeftOverhang : logicalRightOverhang;
    endOverhang = style()->isLeftToRightDirection() ? logicalRightOverhang : logicalLeftOverhang;

    if (!startRenderer || !startRenderer->isText() || startRenderer->style(firstLine)->fontSize() > rubyBase->style(firstLine)->fontSize())
        startOverhang = 0;

    if (!endRenderer || !endRenderer->isText() || endRenderer->style(firstLine)->fontSize() > rubyBase->style(firstLine)->fontSize())
        endOverhang = 0;

    // We overhang a ruby only if the neighboring render object is a text.
    // We can overhang the ruby by no more than half the width of the neighboring text
    // and no more than half the font size.
    int halfWidthOfFontSize = rubyText->style(firstLine)->fontSize() / 2;
    if (startOverhang)
        startOverhang = min<int>(startOverhang, min<int>(toRenderText(startRenderer)->minLogicalWidth(), halfWidthOfFontSize));
    if (endOverhang)
        endOverhang = min<int>(endOverhang, min<int>(toRenderText(endRenderer)->minLogicalWidth(), halfWidthOfFontSize));
}

} // namespace WebCore