To render a text using a font's glyphs, the string of characters must be converted to a sequence of glyphs.
Expected: This happens once per text. Steps of it should be done once per font whenever possible.
Actual: Qt does this when drawing the text. i.e. once per drawing. Therefore it happens twice when drawing a text in two steps (fill and stroke separately). I guess the conversion will also be repeated when a text from <defs> has more than one <use>.