drawWhiteText method Null safety
override
Implementation
@override
void drawWhiteText(Canvas canvas, TextStyle style, String text, double w) {
super.drawWhiteText(canvas, style, text, w);
// Extend the line on the top of the square root symbol
TextSpan span = TextSpan(style: style, text: '\u203E');
TextPainter tp = TextPainter(
text: span,
textAlign: TextAlign.center,
textDirection: TextDirection.ltr);
tp.layout(minWidth: w);
tp.paint(canvas, keyTextOffset.translate(8.4, -2.2));
tp.paint(canvas, keyTextOffset.translate(16, -2.2));
}