Calculates previous and next control points of cubic bezier spline for given point and it's previous and next ones using specified tension. The control points are being calculated in the way to produce smooth line when drawing several parts of it. When drawing a spline using DrawBezierCurve() function you have to specify
cp_next calculated for p1 as
cp1 argument and
cp_prev calculated for p2 as
You can find more information in comments below.
void Bezier(const PointF &prev, const PointF &point, const PointF &next, const float tension, PointF &cp_prev, PointF &cp_next); // Calculate prev and next control point