This code can be used to draw 3D cubic splines by only entering the points through which the spline should pass.
In other words, smooth curves can be drawn by simply defining occasional points through which the curve should pass.
Bezier control points are calculated automatically using the Hobby's algorithm (1986), which allows a slope and "tension" of the spline at each point to be specified explicitly if desired.
@Tgn Yang — for a 2D image I presume. The algorithm generates bezier curves which it plots by sampling the curve with a certain number of "time" points along the curve. You'd have to reverse engineer the algorithm to get the expression for the bezier curve and then integrate that to get the area. Alternatively (preferably) just use numerical integration on the curve that is drawn.
It is very useful, but what should I do if I want to calculate the area of the smoothed picture?
This tool just smooths the edge, but it does not really create new edge, isn't it?