Request G6, Ellipse and G7, bezier curve

void draw_3p_ellipse(double xcen, double ycen, double xend, double yend, double xinput, double yinput, double pi_angle_start, double pi_angle_end, double ratio, double red, double green, double blue, double alpha){

//ellipse center = xcen, ycen
//ellipse base right = xend, yend
//ellipse top point = xinput, yinput

double center_x = xcen;
double center_y = ycen;

//center point to endpoint mayor axis..
double radius_x = sqrt(pow(xend-xcen,2) + pow(yend-ycen,2));
//ratio minor axis to mayor axis..
double radius_y=0;

if(ratio==0){ //takes the controlpoint instead of ratio factor
radius_y = sqrt(pow(xinput-xcen,2) + pow(yinput-ycen,2));
}
if(ratio!=0){ //if ratio from dxf is available, it takes its value
radius_y = ratio*radius_x;
}

//calculate angle of ellipse
double x1=xend;
double y1=yend;
double radian = atan2(y1 - center_y, x1 - center_x);
double angle = radian * (180 / M_PI);
if (angle < 0.0)
angle += 360.0;

glColor4d(red,green,blue,alpha);
glBegin(GL_LINE_STRIP);
for(double j = pi_angle_start; j<pi_angle_end; j+=0.01)
{
//non rotated ellipse..
double non_rotated_x = /*center_x +*/ cos(j)*radius_x;
double non_rotated_y = /*center_y +*/ sin(j)*radius_y;
//glVertex2d(center_x + cos(j)*radius_x, center_y + sin(j)*radius_y);

//rotated ellipse..
double rotate_x = center_x + cos(angle * M_PI / 180.0 )* non_rotated_x - sin(angle * M_PI / 180.0 ) * non_rotated_y;
double rotate_y = center_y + sin(angle * M_PI / 180.0 )* non_rotated_x + cos(angle * M_PI / 180.0 ) * non_rotated_y;
glVertex2d(rotate_x, rotate_y);
}
glEnd();
}

void draw_4p_bezier(double xs, double ys, double zs, double xcon0, double ycon0, double zcon0, double xcon1, double ycon1, double zcon1, double xend, double yend, double zend, double red, double green, double blue, double alpha){
glLineWidth(1);
glColor4d(red,green,blue,alpha);
glBegin(GL_LINE_STRIP);
for(double t = 0; t < 1; t+=0.01){

//Calculate Point E, on the line AB
double Ex = ((1-t) * xs) + (t * xcon0);
double Ey = ((1-t) * ys) + (t * ycon0);
double Ez = ((1-t) * zs) + (t * zcon0);

//Calculate Point F, on the line BC
double Fx = ((1-t) * xcon0) + (t * xcon1);
double Fy = ((1-t) * ycon0) + (t * ycon1);
double Fz = ((1-t) * zcon0) + (t * zcon1);

//Calculate Point G, on the line CD
double Gx = ((1-t) * xcon1) + (t * xend);
double Gy = ((1-t) * ycon1) + (t * yend);
double Gz = ((1-t) * zcon1) + (t * zend);

//Calculate Point Q, on the line EF
double Qx = ((1-t) * Ex) + (t * Fx);
double Qy = ((1-t) * Ey) + (t * Fy);
double Qz = ((1-t) * Ez) + (t * Fz);

//Calculate Point R, on the line FG
double Rx = ((1-t) * Fx) + (t * Gx);
double Ry = ((1-t) * Fy) + (t * Gy);
double Rz = ((1-t) * Fz) + (t * Gz);

//Calculate Point P, on the line QR
double Px = ((1-t) * Qx) + (t * Rx);
double Py = ((1-t) * Qy) + (t * Ry);
double Pz = ((1-t) * Qz) + (t * Rz);

glVertex3d(Px, Py, Pz); //draw linestrip..
}
glEnd();
}