Source/core/rendering/LineWidth.cpp

/*
 * Copyright (C) 2013 Adobe Systems Incorporated. All rights reserved.
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 * modification, are permitted provided that the following conditions
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 *    disclaimer in the documentation and/or other materials
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 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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 * COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
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#include "config.h"
#include "core/rendering/LineWidth.h"

#include "core/rendering/RenderBlock.h"
#include "core/rendering/RenderRubyRun.h"

namespace WebCore {

LineWidth::LineWidth(RenderBlock& block, bool isFirstLine, IndentTextOrNot shouldIndentText)
    : m_block(block)
    , m_uncommittedWidth(0)
    , m_committedWidth(0)
    , m_overhangWidth(0)
    , m_left(0)
    , m_right(0)
    , m_availableWidth(0)
    , m_segment(0)
    , m_isFirstLine(isFirstLine)
    , m_shouldIndentText(shouldIndentText)
{
    updateCurrentShapeSegment();
    updateAvailableWidth();
}

void LineWidth::updateAvailableWidth(LayoutUnit replacedHeight)
{
    LayoutUnit height = m_block.logicalHeight();
    LayoutUnit logicalHeight = m_block.minLineHeightForReplacedRenderer(m_isFirstLine, replacedHeight);
    m_left = m_block.logicalLeftOffsetForLine(height, shouldIndentText(), logicalHeight);
    m_right = m_block.logicalRightOffsetForLine(height, shouldIndentText(), logicalHeight);

    if (m_segment) {
        m_left = std::max<float>(m_segment->logicalLeft, m_left);
        m_right = std::min<float>(m_segment->logicalRight, m_right);
    }

    computeAvailableWidthFromLeftAndRight();
}

void LineWidth::shrinkAvailableWidthForNewFloatIfNeeded(FloatingObject* newFloat)
{
    LayoutUnit height = m_block.logicalHeight();
    if (height < newFloat->logicalTop(m_block.isHorizontalWritingMode()) || height >= newFloat->logicalBottom(m_block.isHorizontalWritingMode()))
        return;

    // When floats with shape outside are stacked, the floats are positioned based on the margin box of the float,
    // not the shape's contour. Since we computed the width based on the shape contour when we added the float,
    // when we add a subsequent float on the same line, we need to undo the shape delta in order to position
    // based on the margin box. In order to do this, we need to walk back through the floating object list to find
    // the first previous float that is on the same side as our newFloat.
    ShapeOutsideInfo* previousShapeOutsideInfo = 0;
    const FloatingObjectSet& floatingObjectSet = m_block.m_floatingObjects->set();
    FloatingObjectSetIterator it = floatingObjectSet.end();
    FloatingObjectSetIterator begin = floatingObjectSet.begin();
    LayoutUnit lineHeight = m_block.lineHeight(m_isFirstLine, m_block.isHorizontalWritingMode() ? HorizontalLine : VerticalLine, PositionOfInteriorLineBoxes);
    for (--it; it != begin; --it) {
        FloatingObject* previousFloat = *it;
        if (previousFloat != newFloat && previousFloat->type() == newFloat->type()) {
            previousShapeOutsideInfo = previousFloat->renderer()->shapeOutsideInfo();
            if (previousShapeOutsideInfo)
                previousShapeOutsideInfo->updateDeltasForContainingBlockLine(&m_block, previousFloat, m_block.logicalHeight(), lineHeight);
            break;
        }
    }

    ShapeOutsideInfo* shapeOutsideInfo = newFloat->renderer()->shapeOutsideInfo();
    if (shapeOutsideInfo)
        shapeOutsideInfo->updateDeltasForContainingBlockLine(&m_block, newFloat, m_block.logicalHeight(), lineHeight);

    if (newFloat->type() == FloatingObject::FloatLeft) {
        float newLeft = newFloat->logicalRight(m_block.isHorizontalWritingMode());
        if (previousShapeOutsideInfo)
            newLeft -= previousShapeOutsideInfo->rightMarginBoxDelta();
        if (shapeOutsideInfo)
            newLeft += shapeOutsideInfo->rightMarginBoxDelta();

        if (shouldIndentText() && m_block.style()->isLeftToRightDirection())
            newLeft += floorToInt(m_block.textIndentOffset());
        m_left = std::max<float>(m_left, newLeft);
    } else {
        float newRight = newFloat->logicalLeft(m_block.isHorizontalWritingMode());
        if (previousShapeOutsideInfo)
            newRight -= previousShapeOutsideInfo->leftMarginBoxDelta();
        if (shapeOutsideInfo)
            newRight += shapeOutsideInfo->leftMarginBoxDelta();

        if (shouldIndentText() && !m_block.style()->isLeftToRightDirection())
            newRight -= floorToInt(m_block.textIndentOffset());
        m_right = std::min<float>(m_right, newRight);
    }

    computeAvailableWidthFromLeftAndRight();
}

void LineWidth::commit()
{
    m_committedWidth += m_uncommittedWidth;
    m_uncommittedWidth = 0;
}

void LineWidth::applyOverhang(RenderRubyRun* rubyRun, RenderObject* startRenderer, RenderObject* endRenderer)
{
    int startOverhang;
    int endOverhang;
    rubyRun->getOverhang(m_isFirstLine, startRenderer, endRenderer, startOverhang, endOverhang);

    startOverhang = std::min<int>(startOverhang, m_committedWidth);
    m_availableWidth += startOverhang;

    endOverhang = std::max(std::min<int>(endOverhang, m_availableWidth - currentWidth()), 0);
    m_availableWidth += endOverhang;
    m_overhangWidth += startOverhang + endOverhang;
}

void LineWidth::fitBelowFloats()
{
    ASSERT(!m_committedWidth);
    ASSERT(!fitsOnLine());

    LayoutUnit floatLogicalBottom;
    LayoutUnit lastFloatLogicalBottom = m_block.logicalHeight();
    float newLineWidth = m_availableWidth;
    float newLineLeft = m_left;
    float newLineRight = m_right;
    while (true) {
        floatLogicalBottom = m_block.nextFloatLogicalBottomBelow(lastFloatLogicalBottom, ShapeOutsideFloatShapeOffset);
        if (floatLogicalBottom <= lastFloatLogicalBottom)
            break;

        newLineLeft = m_block.logicalLeftOffsetForLine(floatLogicalBottom, shouldIndentText());
        newLineRight = m_block.logicalRightOffsetForLine(floatLogicalBottom, shouldIndentText());
        newLineWidth = max(0.0f, newLineRight - newLineLeft);
        lastFloatLogicalBottom = floatLogicalBottom;

        // FIXME: This code should be refactored to incorporate with the code above.
        ShapeInsideInfo* shapeInsideInfo = m_block.layoutShapeInsideInfo();
        if (shapeInsideInfo) {
            LayoutUnit logicalOffsetFromShapeContainer = m_block.logicalOffsetFromShapeAncestorContainer(shapeInsideInfo->owner()).height();
            LayoutUnit lineHeight = m_block.lineHeight(false, m_block.isHorizontalWritingMode() ? HorizontalLine : VerticalLine, PositionOfInteriorLineBoxes);
            shapeInsideInfo->updateSegmentsForLine(lastFloatLogicalBottom + logicalOffsetFromShapeContainer, lineHeight);
            updateCurrentShapeSegment();
            updateAvailableWidth();
        }

        if (newLineWidth >= m_uncommittedWidth)
            break;
    }

    if (newLineWidth > m_availableWidth) {
        m_block.setLogicalHeight(lastFloatLogicalBottom);
        m_availableWidth = newLineWidth + m_overhangWidth;
        m_left = newLineLeft;
        m_right = newLineRight;
    }
}

void LineWidth::updateCurrentShapeSegment()
{
    if (ShapeInsideInfo* shapeInsideInfo = m_block.layoutShapeInsideInfo())
        m_segment = shapeInsideInfo->currentSegment();
}

void LineWidth::computeAvailableWidthFromLeftAndRight()
{
    m_availableWidth = max(0.0f, m_right - m_left) + m_overhangWidth;
}

}