b.c

在VisualC++环境下

  public class DrawEngeCur
 {
        /*funtion:
         *input:(1)g ： Graphics;(2)controlPoints：
         * 　　　(3)penColor，(4)degree　；(5)
         *output:void 
         * call funtion:
         */
        public  static void Bezier(Graphics g , PointF[] controlPoints , Color penColor ,int degree , int n)
  {
            
            //COLOUR
            Pen drawPen = new Pen(penColor);

   int controlPointsNum = controlPoints.Length;
   float[] coeff_x = new float[controlPointsNum];
   float[] coeff_y = new float[controlPointsNum];
   for(int i=0;i<controlPointsNum;i++)
   {
                coeff_x[i] = controlPoints[i].X;
    coeff_y[i] = controlPoints[i].Y;
   }


           
            double t = 0;
            
   float delt = (float)(1.0/n);

            
            PointF pointPre = controlPoints[0];
            
            PointF pointCur = new PointF();

   for(int i=1;i <= n ;i++)
   {
    t = t + delt;
               
                pointCur.X = GetNextPoint(degree,coeff_x,t);
    pointCur.Y = GetNextPoint(degree,coeff_y,t);
    
               
                g.DrawLine(drawPen,pointPre,pointCur);
    
                
                pointPre = pointCur;

   }

   }


         /*funtion:
            *input:(1)(2)　coeff (3)t :
            *output:
            * called funtion:
            */
        private static float GetNextPoint(int degree , float[] coeff ,double t)
  {
            
   int coeffNumb = coeff.Length;
   float[]  coeffXOrY = new float[coeffNumb];
   for(int i=0;i<coeffNumb;i++)
   {
    coeffXOrY[i] = coeff[i];
   }


           
   float tReverse = (float)(1.0 - t);
            
   for(int r=1;r<=degree;r++)
   {
    for(int i =0;i<=degree-r;i++)
    {
     coeffXOrY[i] = (float)(tReverse*coeffXOrY[i]+t*coeffXOrY[i+1]);
    }
   }

            return coeffXOrY[0];
   
  }
 }