procedure TForm1.Button1Click(Sender: TObject);
var
   x1, x2, y1, y2 : integer;
   dx, dy, steps, k : integer;
   xi, yi, x, y : real;
   buf : char;
begin
   x1 := 20;
   x2 := 80;
   y1 := 20;
   y2 := 80;
   buf := '*';
   dx := x2 - x1;
   dy := y2 - y1;
   if abs(dx) > abs(dy) then steps := abs(dx)
     else steps := abs(dy);
   xi := dx / steps;
   yi := dy / steps;
   x := x1;
   y := y1;
   image1.Canvas.TextOut(round(x), round(y), '*');

   for k:=1 to steps do
   begin
     x := x + xi;
     y := y + yi;
     image1.Canvas.TextOut(round(x), round(y), '*');
   end;
end;

end.

---- 소스는 위와같구요... *이 한개만 출력돼네요... DDA알고리즘으로 *을 출력한것인데 그전에 찍었던 별은 없어지는거 같아요...