textsize by screen flutter

Textsize utils

import 'dart:ui';

class TextSizes {
  static TextSizes _instance;

  static const int defaultWidth = 720;
  static const int defaultHeight = 1280;

  num uiWidthPx;
  num uiHeightPx;

  static double _screenWidth;
  static double _screenHeight;
  static double _pixelRatio;

  TextSizes._();

  factory TextSizes() {
    return _instance;
  }

  static void init({num width = defaultWidth, num height = defaultHeight}) {
    if (_instance == null) {
      _instance = TextSizes._();
    }
    _instance.uiWidthPx = width;
    _instance.uiHeightPx = height;
    _pixelRatio = window.devicePixelRatio;
    _screenWidth = window.physicalSize.width;
    _screenHeight = window.physicalSize.height;
    print(_pixelRatio);
    print(_screenWidth);
  }

  static double get pixelRatio => _pixelRatio;

  static double get screenWidth => _screenWidth / _pixelRatio;

  static double get screenHeight => _screenHeight / _pixelRatio;

  double get scaleWidth {
    print("${screenWidth / uiWidthPx}");
    return screenWidth / uiWidthPx;
  }

  double get scaleHeight => screenHeight / uiHeightPx;

  double get scaleText => scaleWidth;

  num setHeight(num height) => height * scaleHeight;

  num setWidth(num width) => width * scaleWidth;

  num setSp(num fontSize) {
    print("${fontSize * scaleText}");
    return fontSize * scaleText;
  }
}