CODE EXAMPLE FOR CSHARP

How to draw Bezier curve?

void recursive_bezier(double x1, double y1, 
                          double x2, double y2, 
                          double x3, double y3, 
                          double x4, double y4)
    {

        // Calculate all the mid-points of the line segments
        //----------------------
        double x12   = (x1 + x2) / 2;
        double y12   = (y1 + y2) / 2;
        double x23   = (x2 + x3) / 2;
        double y23   = (y2 + y3) / 2;
        double x34   = (x3 + x4) / 2;
        double y34   = (y3 + y4) / 2;
        double x123  = (x12 + x23) / 2;
        double y123  = (y12 + y23) / 2;
        double x234  = (x23 + x34) / 2;
        double y234  = (y23 + y34) / 2;
        double x1234 = (x123 + x234) / 2;
        double y1234 = (y123 + y234) / 2;

        // Try to approximate the full cubic curve by a single straight line
        //------------------
        double dx = x4-x1;
        double dy = y4-y1;

        double d2 = fabs(((x2 - x4) * dy - (y2 - y4) * dx));
        double d3 = fabs(((x3 - x4) * dy - (y3 - y4) * dx));

        if((d2 + d3)*(d2 + d3) < m_distance_tolerance * (dx*dx + dy*dy))
        {
            add_point(x1234, y1234);
            return;
        }

        // Continue subdivision
        //----------------------
        recursive_bezier(x1, y1, x12, y12, x123, y123, x1234, y1234); 
        recursive_bezier(x1234, y1234, x234, y234, x34, y34, x4, y4); 
    }


    void bezier(double x1, double y1, 
                double x2, double y2, 
                double x3, double y3, 
                double x4, double y4)
    {
        add_point(x1, y1);
        recursive_bezier(x1, y1, x2, y2, x3, y3, x4, y4);
        add_point(x4, y4);
    }