As the scan begins, the scanner is looking for characters to be drawn. The default at the beginning of a string is to use the font implied by the resource txFont. The function code 'F', without a following integer, implies a return to the font specified by the txFont resource. G selects the Greek font. The default at the beginning of a string is to use the Roman font.
P selects characters of principal size.
I selects characters of indexical size. K selects characters of cartographic size. The default at the beginning of a string is to use characters of principal size. However, when other fonts are used, these codes actually do just affect the size of the character. U or U n selects uppercase.