third_party/WebKit/Source/core/layout/LayoutRubyText.cpp

/*
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 * Copyright (C) 2011 Apple Inc. All rights reserved.
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#include "core/layout/LayoutRubyText.h"

namespace blink {

LayoutRubyText::LayoutRubyText(Element* element) : LayoutBlockFlow(element) {}

LayoutRubyText::~LayoutRubyText() {}

bool LayoutRubyText::isChildAllowed(LayoutObject* child,
                                    const ComputedStyle&) const {
  return child->isInline();
}

ETextAlign LayoutRubyText::textAlignmentForLine(bool endsWithSoftBreak) const {
  ETextAlign textAlign = style()->textAlign();
  // FIXME: This check is bogus since user can set the initial value.
  if (textAlign != ComputedStyle::initialTextAlign())
    return LayoutBlockFlow::textAlignmentForLine(endsWithSoftBreak);

  // The default behavior is to allow ruby text to expand if it is shorter than
  // the ruby base.
  return ETextAlign::Justify;
}

void LayoutRubyText::adjustInlineDirectionLineBounds(
    unsigned expansionOpportunityCount,
    LayoutUnit& logicalLeft,
    LayoutUnit& logicalWidth) const {
  ETextAlign textAlign = style()->textAlign();
  // FIXME: This check is bogus since user can set the initial value.
  if (textAlign != ComputedStyle::initialTextAlign())
    return LayoutBlockFlow::adjustInlineDirectionLineBounds(
        expansionOpportunityCount, logicalLeft, logicalWidth);

  int maxPreferredLogicalWidth = this->maxPreferredLogicalWidth().toInt();
  if (maxPreferredLogicalWidth >= logicalWidth)
    return;

  // Inset the ruby text by half the inter-ideograph expansion amount, but no
  // more than a full-width ruby character on each side.
  LayoutUnit inset = (logicalWidth - maxPreferredLogicalWidth) /
                     (expansionOpportunityCount + 1);
  if (expansionOpportunityCount)
    inset = std::min(LayoutUnit(2 * style()->fontSize()), inset);

  logicalLeft += inset / 2;
  logicalWidth -= inset;
}

bool LayoutRubyText::avoidsFloats() const {
  return true;
}

}  // namespace blink