pfontdesc:SetSize(size)
This is mutually exclusive with pfontdesc:SetAbsoluteSize().
#PANGO_SCALE (that is, a size value of 10 * #PANGO_SCALE is a 10 point font;
the conversion factor between points and device units depends on system configuration and the output device; for screen display,
a logical DPI of 96 is common, in which case a 10 point font corresponds to a 10 * (96 / 72) = 13.3 pixel font. Usepfontdesc:SetAbsoluteSize() if you need a particular size in device units