link graphics

procedure main()
    width := 750
    height := 600
    limit := 100
    WOpen("size="||width||","||height)
    every x:=1 to width & y:=1 to height do
    {
        z:=complex(0,0)
        c:=complex(2.5*x/width-2.0,(2.0*y/height-1.0))
        j:=0
        while j<limit & cAbs(z)<2.0 do
        {
           z := cAdd(cMul(z,z),c)
           j+:= 1
        }
        Fg(mColor(j,limit))
        DrawPoint(x,y)
    }
    WriteImage("./mandelbrot.gif")
    WDone()
end

procedure mColor(x,limit)
   max_color := 2^16-1
   color := integer(max_color*(real(x)/limit))

   return(if x=limit
          then "black"
          else color||","||color||",0")
end

record complex(r,i)

procedure cAdd(x,y)
    return complex(x.r+y.r,x.i+y.i)
end

procedure cMul(x,y)
    return complex(x.r*y.r-x.i*y.i,x.r*y.i+x.i*y.r)
end

procedure cAbs(x)
    return sqrt(x.r*x.r+x.i*x.i)
end