rasterize()

bool MayaFlux::Portal::Text::GlyphAtlas::rasterize ( FontFace &  face, FT_UInt  glyph_index  )

private

Definition at line 124 of file GlyphAtlas.cpp.

{
    FT_Face face = face_ref.get_face();
 
    if (const FT_Error err = FT_Set_Pixel_Sizes(face, 0, m_pixel_size); err != 0) {
        MF_ERROR(Journal::Component::Portal, Journal::Context::API,
            "FT_Set_Pixel_Sizes({}) failed: {}", m_pixel_size, static_cast<int>(err));
        return false;
    }
 
    if (const FT_Error err = FT_Load_Glyph(face, glyph_index, FT_LOAD_RENDER); err != 0) {
        MF_ERROR(Journal::Component::Portal, Journal::Context::API,
            "FT_Load_Glyph({}) failed: {}", glyph_index, static_cast<int>(err));
        return false;
    }
 
    const FT_Bitmap* bmp = &face->glyph->bitmap;
    uint32_t gw = bmp->width;
    uint32_t gh = bmp->rows;
 
    constexpr uint32_t k_pad = 1;
 
    if (m_cursor_x + gw + k_pad > m_atlas_size) {
        m_cursor_x = 0;
        m_cursor_y += m_shelf_height + k_pad;
        m_shelf_height = 0;
    }
 
    if (m_cursor_y + gh + k_pad > m_atlas_size) {
        grow();
 
        // grow() re-rasterized every previously cached glyph, possibly from
        // other faces, which overwrites face->glyph in between; reload
        // this glyph before placing it in the now-larger atlas.
        if (const FT_Error err = FT_Set_Pixel_Sizes(face, 0, m_pixel_size); err != 0) {
            MF_ERROR(Journal::Component::Portal, Journal::Context::API,
                "FT_Set_Pixel_Sizes({}) failed after growth: {}", m_pixel_size, static_cast<int>(err));
            return false;
        }
        if (const FT_Error err = FT_Load_Glyph(face, glyph_index, FT_LOAD_RENDER); err != 0) {
            MF_ERROR(Journal::Component::Portal, Journal::Context::API,
                "FT_Load_Glyph({}) failed after growth: {}", glyph_index, static_cast<int>(err));
            return false;
        }
 
        bmp = &face->glyph->bitmap;
        gw = bmp->width;
        gh = bmp->rows;
 
        if (m_cursor_x + gw + k_pad > m_atlas_size) {
            m_cursor_x = 0;
            m_cursor_y += m_shelf_height + k_pad;
            m_shelf_height = 0;
        }
 
        if (m_cursor_y + gh + k_pad > m_atlas_size) {
            MF_ERROR(Journal::Component::Portal, Journal::Context::API,
                "GlyphAtlas still full after growth to {}x{} at pixel_size={}",
                m_atlas_size, m_atlas_size, m_pixel_size);
            return false;
        }
    }
 
    const std::span<uint8_t> pixels = m_texture->pixel_bytes(0);
    if (pixels.empty()) {
        MF_ERROR(Journal::Component::Portal, Journal::Context::API,
            "GlyphAtlas: TextureContainer pixel_bytes returned empty span");
        return false;
    }
 
    const uint32_t stride = m_atlas_size;
 
    for (uint32_t row = 0; row < gh; ++row) {
        const uint8_t* src = bmp->buffer + static_cast<size_t>(row * static_cast<uint32_t>(std::abs(bmp->pitch)));
        uint8_t* dst = pixels.data() + static_cast<size_t>((m_cursor_y + row) * stride) + m_cursor_x;
        std::memcpy(dst, src, gw);
    }
 
    const float inv = 1.F / static_cast<float>(m_atlas_size);
 
    GlyphMetrics m;
    m.uv_x0 = static_cast<float>(m_cursor_x) * inv;
    m.uv_y0 = static_cast<float>(m_cursor_y) * inv;
    m.uv_x1 = static_cast<float>(m_cursor_x + gw) * inv;
    m.uv_y1 = static_cast<float>(m_cursor_y + gh) * inv;
    m.bearing_x = face->glyph->bitmap_left;
    m.bearing_y = face->glyph->bitmap_top;
    m.width = gw;
    m.height = gh;
    m.advance_x = static_cast<int32_t>(face->glyph->advance.x >> 6);
    m.face = &face_ref;
    m.glyph_index = glyph_index;
 
    m_cache[&face_ref].emplace(glyph_index, m);
 
    m_cursor_x += gw + k_pad;
    if (gh > m_shelf_height) {
        m_shelf_height = gh;
    }
 
    m_dirty = true;
    return true;
}

References MayaFlux::Portal::Text::GlyphMetrics::advance_x, MayaFlux::Journal::API, MayaFlux::Portal::Text::GlyphMetrics::bearing_x, MayaFlux::Portal::Text::GlyphMetrics::bearing_y, dst, MayaFlux::Portal::Text::GlyphMetrics::face, MayaFlux::Portal::Text::FontFace::get_face(), MayaFlux::Portal::Text::GlyphMetrics::glyph_index, grow(), MayaFlux::Portal::Text::GlyphMetrics::height, m_atlas_size, m_cache, m_cursor_x, m_cursor_y, m_dirty, m_pixel_size, m_shelf_height, m_texture, MF_ERROR, pixels, MayaFlux::Journal::Portal, src, MayaFlux::Portal::Text::GlyphMetrics::uv_x0, MayaFlux::Portal::Text::GlyphMetrics::uv_x1, MayaFlux::Portal::Text::GlyphMetrics::uv_y0, MayaFlux::Portal::Text::GlyphMetrics::uv_y1, and MayaFlux::Portal::Text::GlyphMetrics::width.

Referenced by get_or_rasterize_from(), and grow().

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