textScaleFactor property
final
The number of font pixels for each logical pixel.
For example, if the text scale factor is 1.5, text will be 50% larger than the specified font size.
The value given to the constructor as textScaleFactor. If null, will use the MediaQueryData.textScaleFactor obtained from the ambient MediaQuery, or 1.0 if there is no MediaQuery in scope.
Implementation
final double textScaleFactor