%N pgqvp %F $MIR/src/pgqvp.f
%D Inquire viewport size and position
%B
      SUBROUTINE PGQVP (UNITS, X1, X2, Y1, Y2)
      INTEGER UNITS
      REAL    X1, X2, Y1, Y2

 Inquiry routine to determine the current viewport setting.
 The values returned may be normalized device coordinates, inches, mm,
 or pixels, depending on the value of the input parameter CFLAG.

 Arguments:
  UNITS  (input)  : used to specify the units of the output parameters:
                    UNITS = 0 : normalized device coordinates
                    UNITS = 1 : inches
                    UNITS = 2 : millimeters
                    UNITS = 3 : pixels
                    Other values give an error message, and are
                    treated as 0.
  X1     (output) : the x-coordinate of the bottom left corner of the
                    viewport.
  X2     (output) : the x-coordinate of the top right corner of the
                    viewport.
  Y1     (output) : the y-coordinate of the bottom left corner of the
                    viewport.
  Y2     (output) : the y-coordinate of the top right corner of the
                    viewport.
