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() = default;

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

ETextAlign LayoutRubyText::TextAlignmentForLine(
    bool ends_with_soft_break) const {
  ETextAlign text_align = Style()->GetTextAlign();
  // FIXME: This check is bogus since user can set the initial value.
  if (text_align != ComputedStyleInitialValues::InitialTextAlign())
    return LayoutBlockFlow::TextAlignmentForLine(ends_with_soft_break);

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

void LayoutRubyText::AdjustInlineDirectionLineBounds(
    unsigned expansion_opportunity_count,
    LayoutUnit& logical_left,
    LayoutUnit& logical_width) const {
  ETextAlign text_align = Style()->GetTextAlign();
  // FIXME: This check is bogus since user can set the initial value.
  if (text_align != ComputedStyleInitialValues::InitialTextAlign())
    return LayoutBlockFlow::AdjustInlineDirectionLineBounds(
        expansion_opportunity_count, logical_left, logical_width);

  int max_preferred_logical_width = MaxPreferredLogicalWidth().ToInt();
  if (max_preferred_logical_width >= logical_width)
    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 = (logical_width - max_preferred_logical_width) /
                     (expansion_opportunity_count + 1);
  if (expansion_opportunity_count)
    inset = std::min(LayoutUnit(2 * Style()->FontSize()), inset);

  logical_left += inset / 2;
  logical_width -= inset;
}

}  // namespace blink