Canvas. График. Zoom

[NEymexa:c]

В общем, вопрос такой. Есть график. Как организовать зум с помощью canvas? Без использования tchart

[SQLPowerUser]

Можно воспользоваться этой функцией
Но проще рисовать на Image.Canvas

procedure TForm1.FormActivate(Sender: TObject);
var
  xc, yc, x1, y1, y2, m, xd, yd: integer;
  x, y, c, MyStep: Extended;
  ARect: TRect;
  MyColor: TColor;
begin
  ARect := Image1.Canvas.ClipRect;
  Image1.Canvas.Brush.Color := clWhite;
  Image1.Canvas.FillRect(ARect);

  Image1.Canvas.Pen.Color := 11829830;
  MyColor := clGreen;

  xc := ARect.Right div 2;
  yc := Arect.Bottom div 2;
  Image1.Canvas.MoveTo(0,yc); Image1.Canvas.LineTo(ARect.Right, yc); Image1.Canvas.LineTo(ARect.Right-8, yc-4);
  Image1.Canvas.MoveTo(ARect.Right,yc);  Image1.Canvas.LineTo(ARect.Right-8, yc+4);
  Image1.Canvas.MoveTo(xc,ARect.Bottom); Image1.Canvas.LineTo(xc,Arect.Top); Image1.Canvas.LineTo(xc-4,ARect.Top+8);
  Image1.Canvas.MoveTo(xc,ARect.Top); Image1.Canvas.LineTo(xc+4,ARect.Top+8);

  c := 1; m := 100;
  x := -c * sqrt(2);
  MyStep := 0.0009; // ×åì ìåíüøå ýòî ÷èñëî, òåì ëó÷øå êà÷åñòâî
  xd := 0; yd := 0; // Ñìåùåíèå öåíòðà ó ãðàôèêà. Ìîæíî ïîìåíÿòü äëÿ íàãëÿäíîñòè xd := 15; yd := -20;
  while x <= c*sqrt(2) do
  begin
    if sqrt(c*c*c*c+4*x*x*c*c)-x*x-c*c > MyStep then
    begin
      y := sqrt(sqrt(c*c*c*c+4*x*x*c*c)-x*x-c*c);
      x1:= xc + round(x*m);
      y1:= yc - round(y*m);
      y2:= yc + round(y*m);
      Image1.Canvas.Pixels[x1+xd,y1+yd] := MyColor;
      Image1.Canvas.Pixels[x1+xd,y2+yd] := MyColor;
    end;
    x := x + MyStep;
  end;
end;


procedure TForm1.Button1Click(Sender: TObject);
var
  p: integer;
  k: Extended;
begin
  p := 110;
  k := (200-p)/100;

  Image1.Picture.Bitmap.Width := Round(Image1.Width/k);
  Image1.Width := Image1.Picture.Bitmap.Width;
  Image1.Picture.Bitmap.Height := Round(Image1.Height/k);
  Image1.Height := Image1.Picture.Bitmap.Height;

  Image1.Canvas.CopyRect(Rect(0,0, Image1.Width, Image1.Height), Image1.Canvas, Rect(0,0, Round(k*Image1.Width), Round(k*Image1.Height)));
end;


procedure TForm1.Button2Click(Sender: TObject);
var
  p: integer;
  k: Extended;
begin
  p := 90;
  k := (200-p)/100;

  Image1.Width := Round(Image1.Width/k);
  Image1.Height := Round(Image1.Height/k);

  Image1.Canvas.CopyRect(Rect(0,0, Image1.Width, Image1.Height), Image1.Canvas, Rect(0,0, Round(k*Image1.Width), Round(k*Image1.Height)));
end;

[NEymexa:c]

Спасибо. Получилось