import 'math'	// for pi

global class plotPostscript
// A little plotter for postScript
    {
    file f;	// Where to write output

    to init(file f, double width,height)
    // Initialize plotter - need output file and dimensions in
    // points (1 point = 1/72th of an inch.)
       {
       self.f = f;
       f.write("
%!PS-Adobe-3.1 EPSF-3.0
%%BoundingBox: 0 0 $width $height
1.0 setlinewidth
");
       }

    to line(double x1,y1,x2,y2)
    // Draw a line.
       {
       f.write("
$x1 $y1 moveto
$x2 $y2 lineto
stroke
");
       }

    to circle(double xCen,yCen,radius)
    // Draw a circle as a polygon with many sides
       {
       int sides = radius;
       if (sides < 16)
          sides = 16;
       int x = xCen+radius, y=yCen;
       f.write("$x $y moveto\n");
       for (i in 1 til sides)
           {
	   double angle = i * math.pi * 2 / sides;
	   x = xCen + radius * cos(angle);
	   y = yCen + radius * sin(angle);
	   f.write("$x $y lineto\n");
	   }
	f.write("closepath\n");
	f.write("stroke\n");
       }
    }