第五章 绘图基础（BEZIER）

 /*-----------------------------
 BEZIER.C -- Bezier Splines Demo
 (c) Charles Petzold, 1998
 -----------------------------*/

 #include <Windows.h>

 LRESULT CALLBACK WndPorc(HWND, UINT, WPARAM, LPARAM);

 int WINAPI WinMain( __in HINSTANCE hInstance
                     , __in_opt HINSTANCE hPrevInstance
                     , __in LPSTR lpCmdLine
                     , __in int nShowCmd )
 {
     static TCHAR szAppName[] = TEXT("Bezier");
     HWND hwnd;
     MSG msg;
     WNDCLASS wndclass;

     wndclass.style = CS_HREDRAW | CS_VREDRAW;
     wndclass.lpfnWndProc = WndPorc;
     wndclass.cbClsExtra = ;
     wndclass.cbWndExtra = ;
     wndclass.hInstance = hInstance;
     wndclass.hIcon = LoadIcon(NULL, IDI_APPLICATION);
     wndclass.hCursor = LoadCursor(NULL, IDC_ARROW);
     wndclass.hbrBackground = (HBRUSH)GetStockObject(WHITE_BRUSH);
     wndclass.lpszMenuName = NULL;
     wndclass.lpszClassName = szAppName;

     if (!RegisterClass(&wndclass))
     {
         MessageBox(NULL, TEXT("Program requires Windows NT!")
             , szAppName, MB_ICONERROR);
         return ;
     }

     hwnd = CreateWindow(szAppName, TEXT("Bezier Splines")
         , WS_OVERLAPPEDWINDOW
         , CW_USEDEFAULT, CW_USEDEFAULT
         , CW_USEDEFAULT, CW_USEDEFAULT
         , NULL, NULL, hInstance, NULL);

     ShowWindow(hwnd, nShowCmd);
     UpdateWindow(hwnd);

     while (GetMessage(&msg, NULL, , ))
     {
         TranslateMessage(&msg);
         DispatchMessage(&msg);
     }

     return msg.wParam;
 }

 void DrawBezier(HDC hdc, POINT apt[])
 {
     PolyBezier(hdc, apt, );

     MoveToEx(hdc, apt[].x, apt[].y, NULL);
     LineTo(hdc, apt[].x, apt[].y);

     MoveToEx(hdc, apt[].x, apt[].y, NULL);
     LineTo(hdc, apt[].x, apt[].y);
 }

 LRESULT CALLBACK WndPorc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
 {
     static POINT apt[];
     HDC hdc;
     int cxClient, cyClient;
     PAINTSTRUCT ps;

     switch (message)
     {
     case WM_SIZE:
         cxClient = LOWORD(lParam);
         cyClient = HIWORD(lParam);

         apt[].x = cxClient / ;
         apt[].y = cyClient / ;

         apt[].x = cxClient / ;
         apt[].y = cyClient / ;

         apt[].x = cxClient / ;
         apt[].y =  * cyClient / ;

         apt[].x =  * cxClient / ;
         apt[].y = cyClient / ;

         return ;

     case WM_LBUTTONDOWN:
     case WM_RBUTTONDOWN:
     case WM_MOUSEMOVE:
         if (wParam & MK_LBUTTON || wParam & MK_RBUTTON)
         {
             hdc = GetDC(hwnd);
             SelectObject(hdc, GetStockObject(WHITE_PEN));

             DrawBezier(hdc, apt);

             if (wParam & MK_LBUTTON)
             {
                 apt[].x = LOWORD(lParam);
                 apt[].y = HIWORD(lParam);
             }

             if (wParam & MK_RBUTTON)
             {
                 apt[].x = LOWORD(lParam);
                 apt[].y = HIWORD(lParam);
             }

             SelectObject(hdc, GetStockObject(BLACK_PEN));

             DrawBezier(hdc, apt);

             ReleaseDC(hwnd, hdc);
         }
         return ;

     case WM_PAINT:
         InvalidateRect(hwnd, NULL, TRUE);
         hdc = BeginPaint(hwnd, &ps);

         DrawBezier(hdc, apt);

         EndPaint(hwnd, &ps);
         return ;

     case WM_DESTROY:
         PostQuitMessage();
         return ;
     }

     return DefWindowProc(hwnd, message, wParam, lParam);
 }

BEZIER.C

BEZIER程序的显示结果