第七章 鼠标（CONNECT）

 /*
 CONNECT.C -- Connect-the-Dots Mouse Demo Program
             (c) Charles Petzold,1998
 */

 #include <Windows.h>

 #define MAXPOINTS 1000

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

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

     wndclass.style = CS_HREDRAW | CS_VREDRAW;
     wndclass.lpfnWndProc = WndProc;
     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("Connect-the-Points Mouse Demo")
         , 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;
 }

 LRESULT CALLBACK WndProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
 {
     static POINT pt[MAXPOINTS];
     static int iCount;
     HDC hdc;
     int i, j;
     PAINTSTRUCT ps;

     switch (message)
     {
     case WM_LBUTTONDOWN:
         iCount = ;
         InvalidateRect(hwnd, NULL, TRUE);
         return ;

     case WM_MOUSEMOVE:
         if (wParam & MK_LBUTTON && iCount < )
         {
             pt[iCount  ].x = LOWORD(lParam);
             pt[iCount++].y = HIWORD(lParam);

             hdc = GetDC(hwnd);
             SetPixel(hdc, LOWORD(lParam), HIWORD(lParam), );
             ReleaseDC(hwnd, hdc);
         }
         return ;

     case WM_LBUTTONUP:
         InvalidateRect(hwnd, NULL, FALSE);
         return ;

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

         SetCursor(LoadCursor(NULL, IDC_WAIT));
         ShowCursor(TRUE);

         for (i = ; i < iCount - ; ++i)
             for (j = i + ; j < iCount; ++j)
             {
                 MoveToEx(hdc, pt[i].x, pt[i].y, NULL);
                 LineTo(hdc, pt[j].x, pt[j].y);
             }

         ShowCursor(FALSE);
         SetCursor(LoadCursor(NULL, IDC_ARROW));

         EndPaint(hwnd, &ps);
         return ;

     case WM_DESTROY:
         PostQuitMessage();
         return ;
     }

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

CONNECT.C