code: func (f *Fpdf) CurveBezierCubicTo(cx0, cy0, cx1, cy1, x, y float64) {
  	f.curve(cx0, cy0, cx1, cy1, x, y)
  	f.x, f.y = x, y
  }
docs: // CurveBezierCubicTo creates a single-segment cubic Bézier curve. The curve
  // starts at the current stylus location and ends at the point (x, y). The
  // control points (cx0, cy0) and (cx1, cy1) specify the curvature. At the
  // current stylus, the curve is tangent to the straight line between the
  // current stylus location and the control point (cx0, cy0). At the end point,
  // the curve is tangent to the straight line between the end point and the
  // control point (cx1, cy1).
  //
  // The MoveTo() example demonstrates this method.