貝茲路徑繪製

 

  

#include <math.h>//計算階乘double Cal_Factorial(int n){  double fFactorial = 1;  for(int i=2; i<=n; i++)    fFactorial *= i;  return fFactorial;}//貝塞爾實現BOOL _PolyBezier(HDC hDC, //目標DC  const POINT* lpPoints, int nCount, //曲線控制點  LPPOINT ptOrg=NULL) //DC原始座標{  int i, n = nCount - 1;  double *fNi = new double[nCount];  //(n i) = n!/(i!*(n-i)!)  for(i=0; i<nCount; i++)  {    fNi[i] = Cal_Factorial(n) / Cal_Factorial(i) / Cal_Factorial(n - i);  }  MoveToEx(hDC, lpPoints[0].x, lpPoints[0].y, ptOrg);  for(double t=0; t <= 1.0; t+=1E-3)  {    double fx = 0, fy=0;    for(i=0; i<nCount; i++)    {      double fRate = fNi[i] * pow(t, i) * pow(1-t, n-i);      fx += fRate * lpPoints[i].x;      fy += fRate * lpPoints[i].y;    }    LineTo(hDC, (int)fx, (int)fy);    Sleep(1);  }  delete []fNi;  return TRUE;}

//測試代碼

  case WM_PAINT:    {      HDC hdc;      PAINTSTRUCT ps;      hdc=::BeginPaint(hwnd,&ps);      const POINT ptArray[] = { {100, 100}, {200, 500}, {370, 50}, {400, 500}  };      for(int i=0; i<_countof(ptArray); i++)      {        MoveToEx(hdc, ptArray[i].x-5, ptArray[i].y, NULL);        LineTo(hdc, ptArray[i].x+5, ptArray[i].y);        MoveToEx(hdc, ptArray[i].x, ptArray[i].y-5, NULL);        LineTo(hdc, ptArray[i].x, ptArray[i].y+5);      }      _PolyBezier(hdc, ptArray, _countof(ptArray));      ::EndPaint(hwnd,&ps);      return 0;    }

 

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