class LengthItem
extends java.lang.Object
Struct used to store information about length values. Specifically, each item
stores the "length" (which can be thought of as the time elapsed along the
spline path), the "t" value at this length (used to calculate the (x,y) point
along the spline), and the "fraction" which is equal to the length divided by
the total absolute length of the spline. After we calculate all LengthItems
for a give spline, we have a list of entries which can return the t values
for fractional lengths from 0 to 1.