[Flutter] CustomPainter에서 Text 회전

안녕하세요. CutomPainter에서 TextPainter()로 글자를 그릴 때 회전해서 그리는 방법입니다.

var textPainter = TextPainter()
      ..text = TextSpan(text: leftText, style: const TextStyle(color: Colors.black, fontSize: 18))
      ..textDirection = TextDirection.ltr
      ..textAlign = TextAlign.center
      ..layout();
    canvas.save();
    canvas.translate(0, size.height / 2 - textPainter.height / 2 - bottomSize / 2);
    canvas.rotate(-2 * pi / 4);
    textPainter.paint(canvas, const Offset(0, 0));
    canvas.restore();