Method SetText

libs/drape_frontend/gui/gui_text.cpp:358–436

}

void MutableLabel::SetText(LabelResult & result, std::string text, ref_ptr<dp::TextureManager> mng)
{
  if (size_t const sz = text.size(); sz < m_maxLength)
  {
    /// @todo I don't see a better way to clear cached vertices from the previous frame (text value).
    text.append(m_maxLength - sz, ' ');
  }
  else if (sz > m_maxLength)
  {
    text.erase(m_maxLength - 3);
    text.append("...");
  }

  // TODO(AB): Calculate only the length for pre-cached glyphs in a simpler way?
  m_glyphRegions.clear();
  m_shapedText = mng->ShapeSingleTextLine(dp::kBaseFontSizePixels, text, &m_glyphRegions);

  // TODO(AB): Reuse pre-calculated width and height?
  // float maxHeight = m_shapedText.m_maxLineHeightInPixels;
  // float length = m_shapedText.m_lineWidthInPixels;

  float maxHeight = 0.0f;

  std::pair minMaxXPos = {std::numeric_limits<float>::max(), std::numeric_limits<float>::lowest()};
  float offsetLeft = 0;

  glsl::vec2 pen = glsl::vec2(0.0, 0.0);

  ASSERT_EQUAL(m_glyphRegions.size(), m_shapedText.m_glyphs.size(), ());
  for (size_t i = 0; i < m_glyphRegions.size(); ++i)
  {
    std::array<glsl::vec2, 4> normals, maskTex;
    dp::TextureManager::GlyphRegion const & glyph = m_glyphRegions[i];
    auto const & metrics = m_shapedText.m_glyphs[i];
    glsl::vec2 const offsets =
        GetNormalsAndMask(glyph, metrics.m_xOffset, metrics.m_yOffset, m_textRatio, normals, maskTex);

    ASSERT_EQUAL(normals.size(), maskTex.size(), ());

    for (size_t j = 0; j < normals.size(); ++j)
    {
      result.m_buffer.emplace_back(pen + normals[j], maskTex[j]);
      auto const & back = result.m_buffer.back();
      if (back.m_normal.x < minMaxXPos.first)
      {
        minMaxXPos.first = back.m_normal.x;
        offsetLeft = offsets.x;
      }
      minMaxXPos.second = std::max(minMaxXPos.second, back.m_normal.x);
    }

    // TODO(AB): yAdvance is always zero for horizontal layouts.
    pen += glsl::vec2(metrics.m_xAdvance * m_textRatio, metrics.m_yAdvance * m_textRatio);
    maxHeight = std::max(maxHeight, offsets.y + glyph.GetPixelHeight() * m_textRatio);
  }

  float const length = minMaxXPos.second - minMaxXPos.first;
  // "- offset_left" is an approximation