Вывод графика функции

unit Unit1;
 
interface
 
uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls, ExtCtrls, ComCtrls;
 
type
  TForm1 = class(TForm)
    Image1: TImage;
    Panel1: TPanel;
    Label1: TLabel;
    Edit1: TEdit;
    UpDown1: TUpDown;
    Button1: TButton;
    procedure Button1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;
 
var
  Form1: TForm1;
 
implementation
 
{$R *.dfm}
const
  a=400;
  b=200;
var
  i:integer;
  k:real;
  y:real;
  
 
procedure TForm1.Button1Click(Sender: TObject);
begin
k:=StrToFloat(Edit1.Text);
with image1.Canvas do
begin
  image1.Canvas.FillRect(ClientRect);
  pen.color:=clRed;
  moveTO(0,b); lineto(2*a,b);
  moveTO(a,0); lineto(a,2*b);
  for i:=-a to a do
  begin
    y:=sin(k*pi*i/a);
    pixels[i+a,b-round(180*y)]:=clNavy;
    application.ProcessMessages;
    end;
end;
end;
 
end.

const xn=0;
      xk=6*pi;
var
  Form1: TForm1;
 
implementation
 
{$R *.dfm}
function f(x:double):double;
begin
f:=sin(x)+sin(2*x)
end;
procedure TForm1.Button1Click(Sender: TObject);
var x0,y0,i:integer;
    x,mx,my:double;
begin
x:=xn;
//TChart
while x<=xk do
 begin
  Series1.AddXY(x,f(x),'',clRed);
  x:=x+0.01;
 end;
 //линия
 with Image1 do
 begin
  x0:=50;
  y0:=height div 2;
  mx:=(width-x0-20)/xk;
  my:=(y0-50)/2;
  with  Canvas do
   begin
    Brush.Color:=clSkyBlue;
    FillRect(ClipRect);
    moveto(x0,y0);
    Lineto(width-10,y0);
    Moveto(x0,10);
    Lineto(x0,height-10);
    for i:=1 to trunc(xk)+1 do
     begin
      moveto(x0+round(i*mx),y0-3);
      lineto(x0+round(i*mx),y0+3);
      textout(x0+round(i*mx)-5,y0+10,inttostr(i));
     end;
    for i:=1 to 4 do
     begin
      moveto(x0-3,y0-round(i/2*my));
      lineto(x0+3,y0-round(i/2*my));
      textout(x0-25,y0-round(i/2*my)-5,formatfloat('0.0',i/2));
      moveto(x0-3,y0+round(i/2*my));
      lineto(x0+3,y0+round(i/2*my));
      textout(x0-25,y0+round(i/2*my)-5,formatfloat('0.0',i/2));
     end;
    Textout(x0,y0+10,'0');
    Textout(x0-20,y0-5,'0');
    Textout(width-20,y0-20,'X');
    Textout(x0+10,10,'Y');
   end;
  end;
x:=xn;
Image1.Canvas.Pen.Color:=clRed;
while x<=xk do
 begin
 if x=xn then Image1.Canvas.MoveTo(x0+round(x*mx),y0-round(f(x)*my))
  else Image1.Canvas.LineTo(x0+round(x*mx),y0-round(f(x)*my));
  x:=x+0.01;
 end;
 //точки
 with Image2 do
 begin
  x0:=50;
  y0:=height div 2;
  mx:=(width-x0-20)/xk;
  my:=(y0-50)/2;
  with  Canvas do
   begin
    Brush.Color:=clSkyBlue;
    FillRect(ClipRect);
    moveto(x0,y0);
    Lineto(width-10,y0);
    Moveto(x0,10);
    Lineto(x0,height-10);
    for i:=1 to trunc(xk)+1 do
     begin
      moveto(x0+round(i*mx),y0-3);
      lineto(x0+round(i*mx),y0+3);
      textout(x0+round(i*mx)-5,y0+10,inttostr(i));
     end;
    for i:=1 to 4 do
     begin
      moveto(x0-3,y0-round(i/2*my));
      lineto(x0+3,y0-round(i/2*my));
      textout(x0-25,y0-round(i/2*my)-5,formatfloat('0.0',i/2));
      moveto(x0-3,y0+round(i/2*my));
      lineto(x0+3,y0+round(i/2*my));
      textout(x0-25,y0+round(i/2*my)-5,formatfloat('0.0',i/2));
     end;
    Textout(x0,y0+10,'0');
    Textout(x0-20,y0-5,'0');
    Textout(width-20,y0-20,'X');
    Textout(x0+10,10,'Y');
   end;
  end;
x:=xn;
while x<=xk do
 begin
  Image2.Canvas.Pixels[x0+round(x*mx),y0-round(f(x)*my)]:=clRed;
  x:=x+0.01;
 end;
end;