hb_ft_font_changed behavior question

[Benau]

Hello

It seems that cb5ca6b breaks color emoji rendering:

Currently I do this in supertuxkart

    for (FT_Face face : normal_ttf)
    {
        if (!FT_HAS_COLOR(face) ||
            (FT_HAS_COLOR(face) && face->num_fixed_sizes == 0))
        {
            checkFTError(FT_Set_Pixel_Sizes(face, 0, m_shaping_dpi),
                "setting DPI");
        }
        m_hb_fonts.push_back(hb_ft_font_create(face, NULL));

I have to manually do a FT_Select_Size(face, face->num_fixed_sizes - 1) for Noto Color emoji, otherwise the ft_glyph is 'empty' (bits->width / height is zero) (from hb-ft.cc it seems that hb_ft_font_changed is called after hb_ft_font_create)

Or the correct behavior of using hb_ft_font_create is to set pixel / fixed size after that (and manually call hb_ft_font_changed)?

    for (FT_Face face : normal_ttf)
    {
        m_hb_fonts.push_back(hb_ft_font_create(face, NULL));
        if (!FT_HAS_COLOR(face) ||
            (FT_HAS_COLOR(face) && face->num_fixed_sizes == 0))
        {
            checkFTError(FT_Set_Pixel_Sizes(face, 0, m_shaping_dpi),
                "setting DPI");
        }
        if (face->num_fixed_sizes != 0)
        {
            checkFTError(FT_Select_Size(face, face->num_fixed_sizes - 1),
                "setting color emoji size");
        }
        hb_ft_font_changed(m_hb_fonts.back());

[behdad]

To be honest with you the FT_Face interaction, specially around bitmap fonts, is a mess. I'll try to understand what's going on and get back to you. :(.

[behdad]

Unpopular opinion: We should never have written hb-ft. :))

[khaledhosny]

Absolutely. Now we need a time machine :)

[behdad]

Fixed. We'll get a release out.