%N pgswin %F $MIR/src/pgswin.f
%D Set window
%B
      SUBROUTINE PGSWIN (X1, X2, Y1, Y2)
      REAL X1, X2, Y1, Y2

 Change the window in world coordinate space that is to be mapped on
 to the viewport.  Usually PGSWIN is called automatically by PGENV,
 but it may be called directly by the user.

 Arguments:
  X1     (input)  : the x-coordinate of the bottom left corner
                    of the viewport.
  X2     (input)  : the x-coordinate of the top right corner
                    of the viewport (note X2 may be less than X1).
  Y1     (input)  : the y-coordinate of the bottom left corner
                    of the viewport.
  Y2     (input)  : the y-coordinate of the top right corner
                    of the viewport (note Y2 may be less than Y1).
