Set margins in a TMemo

Problem/Question/Abstract:

How to set margins in a TMemo

Answer:

EM_SETRECT message is sent to Memo to fix the size of the canvas of the component.

procedure TForm1.Button1Click(Sender: TObject);
var
  R: TRect;
  LeftMargin: integer;
  RightMargin: integer;
begin
  LeftMargin := 20;
  RightMargin := 10;

  R := Memo1.ClientRect;
  R.Left := R.Left + LeftMargin;
  R.Top := R.Top + 2;
  R.Bottom := R.Bottom - 2;
  R.Right := R.Right - RightMargin;
  SendMessage(Memo1.Handle, EM_SETRECT, 0, Longint(@R));
end;