NAME
    psopn - Open PostScript(PS) output file
    plots - Start a PS page
    plote - End a PS page
    pscls - Close PS output file

SYNOPSIS

      call psopn(pfile, sheet)
  pfile   [char]  PS filename to create or renew
                  If NULL string, PostScript data are output to STDOUT.
  sheet   [char]  Define sheet size (3 characters)
                   1st char: 'A' | 'B';  2nd char: '4' | '3' | '2' | '1' | '0';
                   3rd char: 'P' | 'L'; (P: portrait, L: landscape)
                   4th char 'E' may be added for EPS output )

      call plots(xo, yo)
  xo, yo  [float] Initial origin of coordinates (in cm)

      call plote

      call pscls

NAME
    plot   - Move pen to specified point with/without drawing
              may change origin
    scisor - Define valid range to draw (no effect on 'wcirc'/'wrect')
    factor - Define scaling factor to draw
    where  - Inform pen location and scaling factor

SYNOPSIS

      call plot(xp, yp, md)
  xp, yp  [float] Coordinates (in cm) of point where to move
  md      [int]   If +2 or -2, draw line to (xp,yp), else only move.
                  If minus, origin is changed to the point.

      call scisor(xl, yl, xsz, ysz)
  xl, yl  [float] Bottom left corner coordinates (in cm) of scisoring range
  xsz     [float] Width (in cm) of scisoring range
  ysz     [float] Height (in cm) of scisoring range
        If xsz = ysz = 0., scisoring is disabled.

      call factor(fac)
  fac     [float] Scaling factor
        If specified, actual drawing is magnified/reduced by this factor.

      call where(xw, wy, wfac)
  wx, wy  [float] Variables in which coordinates of pen location are given
  wfac    [float] Variable in which current scaling factor is given

NAME
    newpen - Specify pen number to use
    penatr - Define line specification to a pen number
              There are 8 pen numbers 1-8. Pens 1-4 are initially specified as
              black solid line with thickness 0.01 / 0.03 / 0.06 / 0.10 cm, 
              while pens 5-8 black broken lines.

SYNOPSIS

      call newpen(npen)
  npen    [int]   Select pen number (1-8) to use drawing

      call penatr(jpen, icol, ityp, thick)
  jpen    [int]   Pen number (1-8) to define specification
  icol    [int]   Color value (RGB color or Gray level)
                  0 thru 16777215 : 24bit color code, 8 bit each for R,G,B
                  0 thru -255 : monochromatic gray level from black to white
                   [ 0 : black ; -255,16777215 : white]
  ityp    [int]   Line species
                   [ 0: solid; 1: broken; 2: dotted; 3: chained ]
  thick   [float] Line thickness (in cm)
        Selecting jpen=0 may be used to define temporal definition of line
         specification, which is valid until redefinition of pen number by
         `call penatr(0, ... )` or `call newpen(n)`.

NAME
    wrect  - Draw a rectangle along axes
    wpolyg - Draw a polygon
    wcirc  - Draw a circle/arc
        using current pen specification

SYNOPSIS

      call wrect(xl, yl, xsz, ysz)
  xl, yl  [float] Coordinates (in cm) of base point (usually lower left corner)
                   of the rectangle.
  xsz     [float] Width (in cm)
                  If minus, drawn on the left side of base point.
  ysz     [float] Height (in cm)
                  If minus, drawn on the bottom side of base point.

      call wpolyg(xm, ym, npt, inc)
  xm, ym  [float] Arrays containing coordinates of polygon corners
  npt     [int]   Number of corners (must be 3 or higher)
  inc     [int]   Increment to retrieve coordinates data (must be positive)

      call wcirc(xc, yc, ra, a1, a2)
  xc, yc  [float] Coordinates (in cm) of circle center
  ra      [float] Radius (in cm)
  a1, a2  [float] Starting and ending angle (in degrees) 
                  Angles are measured counterclockwise from +X (to right)
                   direction.
                  If a1>a2, no circle/arc is drawn.