Method extractLine

lib/Epub/Epub/ParsedText.cpp:825–1184

}

void ParsedText::extractLine(const size_t breakIndex, const int pageWidth, const std::vector<uint16_t>& wordWidths,
                             const std::vector<bool>& continuesVec, const std::vector<bool>& noSpaceBeforeVec,
                             const std::vector<size_t>& lineBreakIndices,
                             const std::function<void(std::shared_ptr<TextBlock>)>& processLine,
                             const GfxRenderer& renderer, const int fontId) {
  const size_t lineBreak = lineBreakIndices[breakIndex];
  const size_t lastBreakAt = breakIndex > 0 ? lineBreakIndices[breakIndex - 1] : 0;
  const size_t lineWordCount = lineBreak - lastBreakAt;

  const int firstLineIndent = resolveFirstLineIndent(breakIndex == 0, renderer, fontId);

  // Build line data by moving from the original vectors using index range
  std::vector<std::string> lineWords;
  lineWords.reserve(lineWordCount);
  std::vector<EpdFontFamily::Style> lineWordStyles;
  lineWordStyles.reserve(lineWordCount);

  for (size_t i = 0; i < lineWordCount; ++i) {
    std::string word = std::move(words[lastBreakAt + i]);
    if (containsSoftHyphen(word)) {
      stripSoftHyphensInPlace(word);
    }
    lineWords.push_back(std::move(word));
    lineWordStyles.push_back(wordStyles[lastBreakAt + i]);
  }

  // Calculate total word width for this line, count actual word gaps,
  // and accumulate total natural gap widths (including space kerning adjustments).
  int lineWordWidthSum = 0;
  size_t actualGapCount = 0;
  int totalNaturalGaps = 0;

  for (size_t wordIdx = 0; wordIdx < lineWordCount; wordIdx++) {
    lineWordWidthSum += wordWidths[lastBreakAt + wordIdx];
    // Count gaps: each word after the first creates a gap, unless it's a continuation
    if (wordIdx > 0 && noSpaceBeforeVec[lastBreakAt + wordIdx]) {
      // Unicode break opportunity with no inserted Latin-style space. It is still
      // a stretchable gap for justified CJK/Korean text.
      actualGapCount++;
    } else if (wordIdx > 0 && !continuesVec[lastBreakAt + wordIdx]) {
      actualGapCount++;
      totalNaturalGaps += renderer.getSpaceAdvance(fontId, lastCodepoint(lineWords[wordIdx - 1]),
                                                   firstCodepoint(lineWords[wordIdx]), lineWordStyles[wordIdx - 1]);
    } else if (wordIdx > 0 && continuesVec[lastBreakAt + wordIdx]) {
      // Non-breaking space tokens (" " with continues=true) are visible, stretchable spaces —
      // count them as justifiable gaps so justifyExtra is distributed to them too.
      if (lineWords[wordIdx] == " ") {
        actualGapCount++;
      }
      // Cross-boundary kerning for continuation words (e.g. nonbreaking spaces, attached punctuation)
      totalNaturalGaps += renderer.getKerning(fontId, lastCodepoint(lineWords[wordIdx - 1]),
                                              firstCodepoint(lineWords[wordIdx]), lineWordStyles[wordIdx - 1]);
    }
  }

  // Calculate spacing (account for indent reducing effective page width on first line)
  const int effectivePageWidth = pageWidth - firstLineIndent;
  const bool isLastLine = breakIndex == lineBreakIndices.size() - 1;