set-text-mode in dc<%>

Determines how text is drawn:

• 'solid -- Before text is drawn, the destination area is filled with the text background color (see set-text-background).

• 'transparent -- Text is drawn directly over any existing image in the destination, as if overlaying text written on transparent film.

• (send a-dc set-text-mode mode) -> void
     mode : symbol in '(solid transparent)