Function CreateTextLayout

src/rendering/renderers/TextRenderer.cpp:74–112

}

TextLayout CreateTextLayout(const TextDocument* textDocument,
                            const std::vector<GlyphHandle>& glyphList) {
  TextLayout layout = {};
  auto isVertical = textDocument->direction == TextDirection::Vertical;
  if (!textDocument->boxText) {
    layout.boxRect = tgfx::Rect::MakeEmpty();
    if (isVertical) {
      layout.coordinateMatrix.setRotate(90);
    }
  } else {
    if (isVertical) {
      auto boxRight = textDocument->boxTextPos.x + textDocument->boxTextSize.x;
      layout.boxRect = tgfx::Rect::MakeWH(textDocument->boxTextSize.y, textDocument->boxTextSize.x);
      layout.firstBaseLine = boxRight - textDocument->firstBaseLine;
      layout.coordinateMatrix.setRotate(90);
      layout.coordinateMatrix.postTranslate(boxRight, textDocument->boxTextPos.y);
    } else {
      layout.boxRect = tgfx::Rect::MakeWH(textDocument->boxTextSize.x, textDocument->boxTextSize.y);
      layout.firstBaseLine = textDocument->firstBaseLine - textDocument->boxTextPos.y;
      layout.coordinateMatrix.setTranslate(textDocument->boxTextPos.x, textDocument->boxTextPos.y);
    }
  }
  layout.lineGap = textDocument->leading == 0 ? roundf(textDocument->fontSize * LINE_GAP_FACTOR)
                                              : textDocument->leading;
  layout.tracking = roundf(textDocument->tracking * textDocument->fontSize * 0.001f);
  layout.baselineShift = textDocument->baselineShift;
  layout.justification = textDocument->justification;

  float minAscent = 0, maxDescent = 0;
  for (auto& glyph : glyphList) {
    minAscent = std::min(minAscent, glyph->getAscent());
    maxDescent = std::max(maxDescent, glyph->getDescent());
  }
  // 以 ascent 和 descent 比例计算出行高的上下位置。
  auto lineHeight = textDocument->fontSize * LINE_GAP_FACTOR;
  layout.fontBottom = (maxDescent / (maxDescent - minAscent)) * lineHeight;
  layout.fontTop = layout.fontBottom - lineHeight;
  return layout;
}

static size_t CalculateNextLineIndex(const std::vector<GlyphInfo>& glyphList, size_t index,
                                     float scaleFactor, float maxWidth, float tracking,