10.1.6 Changing splines to lines

Upon accepting a fitted spline (see the previous sections), Limn checks if a straight line would fit the curve as well. If so, that is preferable, since it is much faster to render straight lines than cubic splines.

More precisely, after fitting a cubic spline to a particular (segment of a) curve, Limn finds the straight line between the spline's endpoints, and computes the average distance (see section 10.1.5.3 Finding the spline) between the line and the curve. If the result is less than some threshold, 1 by default, then the spline is provisionally (see the next section) changed to a line.

You can change the theshold with the `-line-threshold' option.