%N tvgraph %F $MIR/src/subs/tv.for
%D Turns the TV graphics planes on and off.
%P jm
%: tv, display
%B
      subroutine tvgraph(chan, onoff)

      implicit none
      integer chan, onoff

   Inputs:
     chan    Graphics Tv Channel to draw on (typically 1 to 4).
     onoff   1 turns the graphics planes on; 0 turns them off.

   Output:
     (none)
