Method ensureGeometryUpdate

src/SFML/Graphics/Text.cpp:758–1334

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void Text::ensureGeometryUpdate() const
{
    // Do nothing, if geometry has not changed and the font texture has not changed
    if (!m_geometryNeedUpdate && m_font->getTexture(m_characterSize).m_cacheId == m_fontTextureId)
        return;

    // Save the current fonts texture id
    m_fontTextureId = m_font->getTexture(m_characterSize).m_cacheId;

    // Mark geometry as updated
    m_geometryNeedUpdate = false;

    // Clear the previous geometry
    m_vertices.clear();
    m_outlineVertices.clear();
    m_glyphs.clear();
    m_bounds = FloatRect();

    // No text: nothing to draw
    if (m_string.isEmpty())
        return;

    // Compute values related to the text style
    const bool  isBold             = m_style & Bold;
    const bool  isUnderlined       = m_style & Underlined;
    const bool  isStrikeThrough    = m_style & StrikeThrough;
    const float underlineOffset    = m_font->getUnderlinePosition(m_characterSize);
    const float underlineThickness = m_font->getUnderlineThickness(m_characterSize);

    // Compute the location of the strikethrough dynamically
    // We use the center point of the lowercase 'x' glyph as the reference
    // We reuse the underline thickness as the thickness of the strikethrough as well
    const float strikeThroughOffset = m_font->getGlyph(U'x', m_characterSize, isBold).bounds.getCenter().y;

    // Precompute the variables needed by the algorithm
    const float whitespaceWidth = m_font->getGlyph(U' ', m_characterSize, isBold).advance;
    const float letterSpacing   = (whitespaceWidth / 3.0f) * (m_letterSpacingFactor - 1.0f);
    const float lineSpacing     = m_font->getLineSpacing(m_characterSize) * m_lineSpacingFactor;
    float       x               = 0.0f;
    auto        y = (m_textOrientation == TextOrientation::Default) ? static_cast<float>(m_characterSize) : 0.0f;

    // Variables used to compute bounds
    auto minX = static_cast<float>(m_characterSize);
    auto minY = static_cast<float>(m_characterSize);
    auto maxX = 0.0f;
    auto maxY = 0.0f;

    // Check that we have a usable font
    const auto  fontId     = m_font->getInfo().id;
    auto* const fontHandle = m_font->getFontHandle();

    assert(fontId && fontHandle && "Font not usable for shaping text");

    // Ensure the font is set to the size expected by the shaper
    if (!m_font->setCurrentSize(m_characterSize))
    {
        assert(false && "Failed to set font size");
        return;