Name:         PGOPEN

Purpose:      open a graphics device

Category:     GRAPHICS

File:         pgplot.src

Author:       T.J. Pearson

Use:          see description below.

Description:

            INTEGER FUNCTION PGOPEN (DEVICE)
            CHARACTER*(*) DEVICE
      
       Open a graphics device for PGPLOT output. If the device is
       opened successfully, it becomes the selected device to which
       graphics output is directed until another device is selected
       with PGSLCT or the device is closed with PGCLOS.
      
       The value returned by PGOPEN should be tested to ensure that
       the device was opened successfully, e.g.,
      
             ISTAT = PGOPEN('LCPSFILE')
             IF (ISTAT .LE. 0 ) STOP
      
       Note that PGOPEN must be declared INTEGER in the calling program.
      
       The DEVICE argument is a character constant or variable, which must
       be a known GIPSY graphics device, i.e. it must be listed in
       $gip_loc/grdevices.

       [This routine was added to PGPLOT in Version 5.1.0. Older programs
       use PGBEG instead.]
      
       Returns:
        PGOPEN          : returns either a positive value, the
                          identifier of the graphics device for use with
                          PGSLCT, or a 0 or negative value indicating an
                          error. In the event of error a message is
                          written on the standard error unit.
       Arguments:
        DEVICE  (input) : the 'device specification' for the plot device
                          (see above).

Updates:      Oct 16, 1998: JPT extracted from source; modified for GIPSY.
              Dec  3, 1998: JPT call REJECT for invalid device input.
              Apr  7, 2000: JPT initialize image interpolation mode.