memoAutoSizeHeight Delphi

{
Usage example: place this code in your TMemo onChange event
  memoAutoSizeHeight(Memo1, Form1.Canvas, 277);
Note: 277 is the preferred max size of the TMemo height, change on your needs
Reference: http://www.delphigroups.info/2/59/101367.html
}

procedure memoAutoSizeHeight(memo: TMemo; formCanvas: TCanvas; maxHeight: Integer);
var
  rectA, rectB: TRect;
  s: String;
  saveFont: TFont;
  heightResult: Integer;
begin
  try
    s:=memo.Text;
    memo.Perform(EM_GETRECT, 0, LongInt(@rectA));
    rectB:=rectA;
    saveFont:=TFont.Create;
    try
      saveFont.Assign(formCanvas.Font);
      formCanvas.Font:=memo.Font;
      DrawTextEx(formCanvas.Handle, pChar(S), Length(S), rectB,
        DT_CALCRECT or DT_EDITCONTROL or DT_WORDBREAK or DT_NOPREFIX, nil);
    finally
      formCanvas.Font:=saveFont;
      saveFont.Free;
    end;
    heightResult:=memo.Height+rectB.Bottom-rectA.Bottom;
    if Copy(memo.Text, Length(memo.Text)-1, 1)=#13 then
      heightResult:=heightResult+memo.Font.Height;
    if (heightResult>=maxHeight) or (heightResult-memo.Font.Height>=maxHeight) then
      heightResult:=maxHeight;
  finally
    memo.Height:=heightResult;
  end;
end;