positionRange(for:)
Returns the range of x and y positions for the given pair of data values, or nil if the y scale is unavailable or if the value is invalid.
Declaration
func positionRange<X, Y>(for point: (x: X, y: Y)) -> CGRect? where X : Plottable, Y : PlottableReturn Value
The position range corresponding to the data values.
Discussion
For a continuous data value, the returned range is a single point. For a categorical data value, the returned range is the range of positions that correspond to the given category.