Фрактал Ньютона

unit Unit1;
 
{$mode objfpc}{$H+}
 
interface
 
uses
  Classes, SysUtils, FileUtil, Forms, Controls, Graphics, Dialogs, StdCtrls,
  ExtCtrls;
 
type
 
  { TForm1 }
 
  TForm1 = class(TForm)
    Button1: TButton;
    PaintBox1: TPaintBox;
    procedure Button1Click(Sender: TObject);
  private
    { private declarations }
  public
    { public declarations }
  end;
 
var
  Form1: TForm1;
 
implementation
 
{$R *.lfm}
 
{ TForm1 }
 
procedure TForm1.Button1Click(Sender: TObject);
type
	Complex = Record
		x : Real;
		y : Real;
	end;
const
	iter = 50;
	max  = 1e+6;
	min  = 1e-6;
 
var
	z, t, d : Complex;
	p       :  Real;
	x, y, n : Integer;
	Cancel  : Boolean;
	gd, gm  : Smallint;
	mx, my  : Integer;
        col: TColor;
begin
  Randomize;
  PaintBox1.Canvas.Clear;
   Mx := PaintBox1.Canvas.Width div 2;
   My := PaintBox1.Canvas.Height div 2;
 
         for y := -my to my do
		for x := -mx to mx do
		begin
			n := 0;
			z.x := X * 0.005;
			z.y := Y * 0.005;
			d := z;
			while (sqr(z.x)+sqr(z.y) < max) and (sqr(d.x)+sqr(d.y) > min)
				and (n < iter) do
			begin
				t := z;
				{z^3 - 1}
				p := sqr(sqr(t.x)+sqr(t.y));
				z.x := 2/3*t.x + (sqr(t.x)-sqr(t.y))/(3*p);
				z.y := 2/3*t.y*(1-t.x/p);{}
				d.x := abs(t.x - z.x);
				d.y := abs(t.y - z.y);
				Inc(n);
 
			end;
 
                        col := (n*9) mod 255;
                        PaintBox1.Canvas.Pixels[mx+x,my+y]:=RGBTOColor(col,0,col);
 
		end;
 
 
end;
 
end.