glow method
Soft blurred underlay drawn beneath a line/shape for depth. Returns an invisible paint for ChartStyle.flat (draws nothing).
Implementation
Paint glow(Color color, {double strokeWidth = 6, double blur = 6}) {
if (style == ChartStyle.flat) {
return Paint()..color = const Color(0x00000000);
}
final alpha = style == ChartStyle.glass ? 0.16 : 0.22;
return Paint()
..color = color.withValues(alpha: alpha)
..strokeWidth = strokeWidth
..style = PaintingStyle.stroke
..strokeCap = StrokeCap.round
..strokeJoin = StrokeJoin.round
..maskFilter = MaskFilter.blur(BlurStyle.normal, blur)
..isAntiAlias = true;
}