getLineValues
open fun getLineValues(context: ChartDrawContext, visibleXRange: ClosedFloatingPointRange<Float>, fullXRange: ClosedFloatingPointRange<Float>): List<Float>?
Returns, as a list, the x values for which ticks and guidelines are to be displayed, restricted to visibleXRange and with an extra value on either side (if applicable). If null is returned, the values returned by getLabelValues are used.