Scroll image with ScrollBars

If your picture has very large width or height, then you may use ScrollBars for scrolling of this picture. For example, ScrollBar1 will change a horizontal position of this picture and ScrollBar2 will change a vertical position of this picture. Set OnChange event to Scrollbar2Change for each ScrollBar.

var
  MyBitmap: TBitmap;

...

procedure TForm1.ScrollBar2Change(Sender: TObject);
var
  RectDest, RectSource: TRect;
begin
  RectDest:=Rect(0, 0, Image1.Width, Image1.Height);
  RectSource:=Rect(
    ScrollBar1.Position, 
    ScrollBar2.Position, 
    Scrollbar1.Position+Image1.Width, 
    ScrollBar2.Position+Image1.Height);
  Image1.Canvas.CopyRect(RectDest, MyBitmap.Canvas, RectSource);
end;

procedure TForm1.FormCreate(Sender: TObject);
begin
  MyBitmap:=TBitmap.Create;
  MyBitmap.LoadFromFile('factory.bmp');
  Image1.Picture.Bitmap.Assign(MyBitmap);
  ScrollBar1.Max:=MyBitmap.Width-1-Image1.Width;
  ScrollBar2.Max:=MyBitmap.Height-1-Image1.Height;
end;