Approximating curves

Given a curve, which is a line graph, we want to reduce the number of vertices. However, the resulting curve should look like the original one. This is an optimization problem formulated as follows:
Input: A sequence of points, v₁, ... v_n, and a real e, an allowable error.
Output: A subset v_i₁, ... v_{i_s} of input vertices, such that for each j and k (1 <= j <= s-1, i_j <= k <= v_{i_(j+1)}), the distance between a point v_k and a segment v_{i_j}v_{i_(j+1)} is at most e.
Measure: The number of selected points, i.e., s.
This applet realizes the algorithm given in the following paper.
H. Imai and M. Iri, ``Computational-Geometric Methods for Polygonal Approximation of a Curve,'' Computer Vision, Graphics and Image Processing, 36, pp. 31--41, 1986.
How to use the applet
1) Draw a curve using the right button of the mouse.
2) Set e using the scroll bar.
3) Click "show graph" with the left button. Red edges are candidates for output edges.
4) Click "compute" with the left button. Blue edges constitute an optimal solution.

Known bugs.
For 3) and 4) above, you should click buttons twice.