...zoom a Canvas?

procedure SetCanvasZoomFactor(Canvas: TCanvas; AZoomFactor: Integer);
var
  i: Integer;
begin
  if AZoomFactor = 100 then
    SetMapMode(Canvas.Handle, MM_TEXT)
  else
  begin
    SetMapMode(Canvas.Handle, MM_ISOTROPIC);
    SetWindowExtEx(Canvas.Handle, AZoomFactor, AZoomFactor, nil);
    SetViewportExtEx(Canvas.Handle, 100, 100, nil);
  end;
end;


procedure TForm1.Button1Click(Sender: TObject);
var
  bitmap: TBitmap;
begin
  bitmap := TBitmap.Create;
  try
    bitmap.Assign(Form1.image1.Picture.Bitmap);
    SetCanvasZoomFactor(bitmap.Canvas, 70);
    Canvas.Draw(30, 30, bitmap);
  finally
    bitmap.Free
  end;
end;

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