第八章 计时器（DIGCLOCK）

 /*--------------------------------------
 DIGCLOCK.C -- Digital Clock
               (c) Charles Petzold, 1998
 --------------------------------------*/

 #include <Windows.h>

 #define ID_TIMER 1

 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("DigClock");
     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("Digital Clock")
         , 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 DisplayDigit(HDC hdc, int iNumber)
 {
     static BOOL fSevenSegment[][] =
     {
         , , , , , , ,    //
         , , , , , , ,    //
         , , , , , , ,    //
         , , , , , , ,    //
         , , , , , , ,    //
         , , , , , , ,    //
         , , , , , , ,    //
         , , , , , , ,    //
         , , , , , , ,    //
         , , , , , ,         //
     };

     static POINT ptSegment[][] =
     {
         , , , , , , , , , , , ,
         , , , , , , , , , , , ,
         , , , , , , , , , , , ,
         , , , , , , , , , , , ,
         , , , , , , , , , , , ,
         , , , , , , , , , , , ,
         , , , , , , , , , , ,  

     };

     for (int iSeg(); iSeg != ; ++iSeg)
     {
         if (fSevenSegment[iNumber][iSeg])
             Polygon(hdc, ptSegment[iSeg], );
     }
 }

 void DisplayTwoDigits(HDC hdc, int iNumber, BOOL fSuppress)
 {
     if (!fSuppress || (iNumber /  != ))
         DisplayDigit(hdc, iNumber / );

     OffsetWindowOrgEx(hdc, -, , NULL);
     DisplayDigit(hdc, iNumber % );
     OffsetWindowOrgEx(hdc, -, , NULL);
 }

 void DisplayColon(HDC hdc)
 {
     POINT ptColon[][] = { , , , , , , , ,
                             , , , , , , ,  };

     Polygon(hdc, ptColon[], );
     Polygon(hdc, ptColon[], );

     OffsetWindowOrgEx(hdc, -, , NULL);
 }

 void DisplayTime(HDC hdc, BOOL f24Hour, BOOL fSuppress)
 {
     SYSTEMTIME st;

     GetLocalTime(&st);

     if (f24Hour)
         DisplayTwoDigits(hdc, st.wHour, fSuppress);
     else
         DisplayTwoDigits(hdc, (st.wHour %= ) ? st.wHour : , fSuppress);

     DisplayColon(hdc);
     DisplayTwoDigits(hdc, st.wMinute, FALSE);
     DisplayColon(hdc);
     DisplayTwoDigits(hdc, st.wSecond, FALSE);
 }

 LRESULT CALLBACK WndProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
 {
     static BOOL f24Hour, fSuppress;
     static HBRUSH hBrushRed;
     static int cxClient, cyClient;
     HDC hdc;
     PAINTSTRUCT ps;
     TCHAR szBuffer[];

     switch (message)
     {
     case WM_CREATE:
         hBrushRed = CreateSolidBrush(RGB(, , ));
         SetTimer(hwnd, ID_TIMER, , NULL);

         //fall through
     case WM_SETTINGCHANGE:
         GetLocaleInfo(LOCALE_USER_DEFAULT, LOCALE_ITIME, szBuffer, );
         f24Hour = (szBuffer[] == TEXT(''));

         GetLocaleInfo(LOCALE_USER_DEFAULT, LOCALE_ITLZERO, szBuffer, );
         fSuppress = (szBuffer[] == TEXT(''));

         InvalidateRect(hwnd, NULL, TRUE);
         return ;

     case WM_SIZE:
         cxClient = LOWORD(lParam);
         cyClient = HIWORD(lParam);
         return ;

     case WM_TIMER:
         InvalidateRect(hwnd, NULL, TRUE);
         return ;

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

         SetMapMode(hdc, MM_ISOTROPIC);
         SetWindowExtEx(hdc, , , NULL);
         SetViewportExtEx(hdc, cxClient, cyClient, NULL);

         SetWindowOrgEx(hdc, , , NULL);
         SetViewportOrgEx(hdc, cxClient / , cyClient / , NULL);
         SelectObject(hdc, GetStockObject(NULL_PEN));
         SelectObject(hdc, hBrushRed);

         DisplayTime(hdc, f24Hour, fSuppress);

         EndPaint(hwnd, &ps);
         return ;

     case WM_DESTROY:
         KillTimer(hwnd, ID_TIMER);
         DeleteObject(hBrushRed);
         PostQuitMessage();
         return ;
     }

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

DIGCLOCK.C