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