getAnnotationDatum method

@override DatumAnnotation getAnnotationDatum(Axis<Object> axis)

Generates a datum that describes an annotation. This can be implemented to customize annotation positioning.

We can't use Axis

Implementation

@override
DatumAnnotation getAnnotationDatum(Axis<Object> axis) {
  // Remove floating point rounding errors by rounding to 2 decimal places of
  // precision. The difference in the canvas is negligible.
  final startPosition = (axis.getLocation(startValue)! * 100).round() / 100;
  final endPosition = (axis.getLocation(endValue)! * 100).round() / 100;

  return DatumAnnotation(
      startPosition: startPosition,
      endPosition: endPosition,
      axisType: axisType);
}