procedure TForm1.Button1Click(Sender: TObject); var rgn: HRGN; r: TRect; begin r := memo1.ClientRect; rgn := CreateRoundRectRgn(r.Left, r.top, r.right, r.bottom, 20, 20); memo1.BorderStyle := bsNone; memo1.Perform(EM_GETRECT, 0, lparam(@r)); InflateRect(r, -5, -5); memo1.Perform(EM_SETRECTNP, 0, lparam(@r)); SetWindowRgn(memo1.Handle, rgn, true); end;