textStyle property

TextStyle? textStyle

The style to use for the gauge title text.

Using TextStyle to add the style to the axis labels.

Defaults to the TextStyle property with font size 12.0 and font family Segoe UI.

Also refer TextStyle

Widget build(BuildContext context) {
   return Container(
       child: SfRadialGauge(
           title: GaugeTitle(
                   text: 'Gauge Title',
                   textStyle: TextStyle(
                                color: Colors.red,
                                fontSize: 12,
                                fontStyle: FontStyle.normal,
                                fontWeight: FontWeight.w400,
                                fontFamily: 'Roboto'
                              ))
       ));
}

Implementation

final TextStyle? textStyle;