devicePixelRatio property
The pixel ratio of the current device.
Should be obtained by querying MediaQuery for the devicePixelRatio.
Implementation
double get devicePixelRatio => _devicePixelRatio;Implementation
set devicePixelRatio(double value) {
  if (devicePixelRatio == value) {
    return;
  }
  _devicePixelRatio = value;
  markNeedsLayout();
}