%N tvcursor %F $MIR/src/subs/tv.for
%D Read the location of the image display device's cursor.
%P jm
%: tv, display
%B
        subroutine TVcursor(x,y,button)

        implicit none
        integer x,y,button

  Read the current cursor/track ball position, and return the number of
  the last button pressed.

  Output:
    x,y        Cursor screen position (not image memory position).
    button     The number of the last button pressed, This varies from
               1 upwards. A value of zero indicates no button has been
               pushed.
