drawText method
Implementation
@override
void drawText(Canvas canvas, MACDEntity data, double x) {
TextSpan? span = indicator.drawFigure(data, fixedLength, chartColors);
if (span == null) return;
TextPainter tp = TextPainter(text: span, textDirection: TextDirection.ltr);
tp.layout();
tp.paint(canvas, Offset(x, chartRect.top - topPadding));
}