Fetches the kerning-adjustment value for a glyph-pair in the specified font, for horizontal text segments.
<note>It handles legacy kerning only (as returned by the corresponding #hb_font_funcs_t function).</note>
#hb_font_t to work upon
The glyph ID of the left glyph in the glyph pair
The glyph ID of the right glyph in the glyph pair
The kerning adjustment value
Fetches the kerning-adjustment value for a glyph-pair in the specified font, for horizontal text segments.
<note>It handles legacy kerning only (as returned by the corresponding #hb_font_funcs_t function).</note>