The Graph2d makes use of <ahref="http://en.wikipedia.org/wiki/Centripetal_Catmull%E2%80%93Rom_spline"target="_blank">Catmull-Rom spline interpolation</a>.
The user can configure these per group, or globally. In this example we show all 4 possiblities. The differences are in the parametrization of
the curves. The options are <code>uniform</code>, <code>chordal</code> and <code>centripetal</code>. Alternatively you can disable the Catmull-Rom interpolation and
a linear interpolation will be used. The <code>centripetal</code> parametrization produces the best result (no self intersection, yet follows the line closely) and is therefore the default setting.
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For both the <code>centripetal</code> and <code>chordal</code> parametrization, the distances between the points have to be calculated and this makes these methods computationally intensive
if there are very many points. The <code>uniform</code> parametrization still has to do transformations, though it does not have to calculate the distance between point. Finally, the
linear interpolation is the fastest method. For more on the Catmull-Rom method, <ahref="http://www.cemyuksel.com/research/catmullrom_param/catmullrom.pdf"target="_blank">C. Yuksel et al. have an interesting paper titled ″On the parametrization of Catmull-Rom Curves″</a>.
