A curve_point is a point of a path that is reached by a Bezier curve
from the previous point. With one control point (curve_point<-control2
is @nil) the
curve is quadratic, with two it is cubic. The control points are in the
same coordinate system as the points of the path and are moved and
scaled with them.
new(P, path),
send_list(P, append, [ point(0,50),
curve_point(100,50, point(30,0), point(70,100))
]).
See also class path, class arc_point and class bezier_curve.