function plotOrigin(pos, vrange)
{
 var x = 0;
 var y = (pos + (vrange/2)) * this.h / vrange;
 
 if (y > 0 && y < this.h) 
 {
  this.eps.writeln('0 ',y.toFixed(2),' moveto 0 4 rlineto 5 -4 rlineto -5 -4 rlineto closepath fill');
 }
}

function plotTrace(list, ymu, vrange,label,label2)
{
 if (label2)
 {
  this.eps.writeln(this.w - 60,' ',this.labely,' m (',label2,') show');  
 }
 if (label)
 {
  this.eps.writeln(this.w - 100,' ',this.labely,' m (',label,') show');
  this.labely -= 15;
 }
 
 
 var x = 0;
 var y = (list[0] * ymu + (vrange/2)) * this.h / vrange;
 
 if (y < 0) y=0;
 if (y > this.h) y=this.h;
 this.eps.writeln(x.toFixed(2),' ',y.toFixed(2),' m');
 for (var i=1; i<list.length; i++)
 {
  x = this.w * i / list.length;
  y = (list[i] * ymu  + (vrange/2)) * this.h / vrange;
  if (y < 0) y=0;
  if (y > this.h) y=this.h;
  
  this.eps.writeln(x.toFixed(2),' ',y.toFixed(2),' l'); 
  
 }
 this.eps.writeln('stroke');
}

function plotGraticule()
{
 this.eps.writeln('%graticule');
 this.eps.writeln('0.8 setgray [1 ',(this.h/50 - 1).toFixed(2),'] 0 setdash');
 for (var i=1; i<10; i++)
  { 
  if (i == 5) continue;
  this.eps.writeln(this.w * i / 10,' 0 moveto 0 ',this.h,' rlineto stroke');
  }
 this.eps.writeln('0.8 setgray [1 ',(this.w/50 - 1).toFixed(2),'] 0 setdash');
 for (var i=1; i<10; i++)
  { 
  if (i == 5) continue;
  this.eps.writeln('0 ',this.h*i/10,' moveto ', this.w,' 0 rlineto stroke');
  }
 this.eps.writeln('[] 0 setdash');
 this.eps.writeln(this.w/2,' 0 moveto 0 ',this.h,' rlineto stroke');
 this.eps.writeln('0 ',this.h/2,' moveto ', this.w,' 0 rlineto stroke');
}

function plotHeader()
{
 this.eps.writeln("%!PS-Adobe-3.0 EPSF-3.0");
 this.eps.writeln("%%BoundingBox: 0 0 ",this.w," ",this.h);
 this.eps.writeln("%%PaperSize: ",this.w," ",this.h);
 this.eps.writeln("%%Creator:");
 this.eps.writeln("%%Title:");
 this.eps.writeln("%%DocumentFonts: Courier Helvetica Helvetica-Bold");
 this.eps.writeln("%%DocumentNeededFonts: Courier Helvetica Helvetica-Bold");
 this.eps.writeln("gsave");
 this.eps.writeln("/m {moveto} def /l {lineto} def");
 this.eps.writeln("/Helvetica findfont 10 scalefont setfont");
}

function plotFinish()
{
 this.eps.writeln("grestore");
}

function plotRGB(r,g,b)
{
 this.eps.writeln((r/255).toFixed(3),' ',(g/255).toFixed(3),' ',(b/255).toFixed(3),' setrgbcolor');
}

function plotColor(i)
{
 this.eps.writeln(this.colors[i],' setrgbcolor');
}

function plotLabel(freq, rate)
{
//draw box and labels
this.eps.writeln("0 setgray 0 0 moveto ",this.w," 0 rlineto 0 ",this.h," rlineto -",this.w," 0 rlineto closepath stroke");
this.eps.writeln('5 ',this.h-15,' m (', freq.toFixed(1),' Hz) show');
this.eps.writeln('5 ',this.h-27,' m (', (1000*rate).toFixed(1),' ms/div) show');
}

function Plot(eps,w,h,colors)
{
 if (colors)
   this.colors = this.colors.concat(colors);
 else
   this.colors = [".75 .75 0","0 0 1","1 0 0","0 .75 0"];
 
 this.w = w;
 this.h = h;
 this.labely = h - 15;
 this.eps = eps;
 this.trace = plotTrace;
 this.finish= plotFinish; 
 this.graticule = plotGraticule;
 this.color = plotColor;
 this.rgbcolor = plotRGB;
 this.label = plotLabel;
 this.header = plotHeader;
 this.origin = plotOrigin;
 this.header();
}