Get drawing mode. Note only one device driver (cairo) currently supports this at the moment, and for that case the PLINT value returned by this function is one of PL_DRAWMODE_DEFAULT, PL_DRAWMODE_REPLACE, PL_DRAWMODE_XOR, or PL_DRAWMODE_UNKNOWN. This function returns PL_DRAWMODE_UNKNOWN for the rest of the device drivers. See also plsdrawmode(3plplot).
Redacted form: plgdrawmode()
This function is used in example 34.