beeper1.c

定时器实例

/*-----------------------------------------
   BEEPER1.C  -- Timer Demo Program No. 1
                 (c) Charles Petzold, 1996
  -----------------------------------------*/

#include <windows.h>

#define ID_TIMER    1

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

int WINAPI WinMain (HINSTANCE hInstance, HINSTANCE hPrevInstance,
                    PSTR szCmdLine, int iCmdShow)
     {
     static char szAppName[] = "Beeper1" ;
     HWND        hwnd ;
     MSG         msg ;
     WNDCLASSEX  wndclass ;

	 wndclass.cbSize        = sizeof (wndclass) ;
     wndclass.style         = CS_HREDRAW | CS_VREDRAW ;
     wndclass.lpfnWndProc   = WndProc ;
     wndclass.cbClsExtra    = 0 ;
     wndclass.cbWndExtra    = 0 ;
     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 ;
	 wndclass.hIconSm       = LoadIcon (NULL, IDI_APPLICATION) ;

     RegisterClassEx (&wndclass) ;

     hwnd = CreateWindow (szAppName, "Beeper1 Timer Demo",
                          WS_OVERLAPPEDWINDOW,
                          CW_USEDEFAULT, CW_USEDEFAULT,
                          CW_USEDEFAULT, CW_USEDEFAULT,
                          NULL, NULL, hInstance, NULL) ;

     while (!SetTimer (hwnd, ID_TIMER, 1000, NULL))
          if (IDCANCEL == MessageBox (hwnd,
                              "Too many clocks or timers!", szAppName,
                              MB_ICONEXCLAMATION | MB_RETRYCANCEL))
               return FALSE ;

     ShowWindow (hwnd, iCmdShow) ;
     UpdateWindow (hwnd) ;

     while (GetMessage (&msg, NULL, 0, 0))
          {
          TranslateMessage (&msg) ;
          DispatchMessage (&msg) ;
          }
     return msg.wParam ;
     }

LRESULT CALLBACK WndProc (HWND hwnd, UINT iMsg, WPARAM wParam, LPARAM lParam)
     {
     static BOOL fFlipFlop = FALSE ;
     HBRUSH      hBrush ;
     HDC         hdc ;
     PAINTSTRUCT ps ;
     RECT        rc ;

     switch (iMsg)
          {
          case WM_TIMER :
               MessageBeep (0) ;

               fFlipFlop = !fFlipFlop ;
               InvalidateRect (hwnd, NULL, FALSE) ;

               return 0 ;

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

               GetClientRect (hwnd, &rc) ;

               hBrush = CreateSolidBrush (fFlipFlop ? RGB(255,0,0) :
                                                      RGB(0,0,255)) ;
               FillRect (hdc, &rc, hBrush) ;
               EndPaint (hwnd, &ps) ;
               DeleteObject (hBrush) ;
               return 0 ;

          case WM_DESTROY :
               KillTimer (hwnd, ID_TIMER) ;
               PostQuitMessage (0) ;
               return 0 ;
          }
     return DefWindowProc (hwnd, iMsg, wParam, lParam) ;
     }