Programming Windows程式開發設計指南->第五章 例子程式6

/*_############################################################################
  _##
  _##  Programming Windows程式開發設計指南->第五章 例子程式6
  _##  Author: xwlee                        
  _##  Time: 2007.06.20 
  _##  Chang'an University
  _##  Development condition: win2003 Server+VC6.0
  _##
  _##  程式5-6  RANDRECT
  _##  RANDRECT.C 檔案
  _##  不停地顯示隨機矩形的程式
  _##  程式只是進行驗證
  _## 
  _##
  _##    RANDRECT.C --     Displays Random Rectangles
  _##     (c) Charles Petzold, 1998
  _##  
  _##########################################################################*/

#include <windows.h>

#include <stdlib.h> // for the rand function

 

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

void DrawRectangle (HWND) ;

 

int cxClient, cyClient ;

int WINAPI WinMain (HINSTANCE hInstance, HINSTANCE hPrevInstance,

                       PSTR szCmdLine, int iCmdShow)

{

       static TCHAR szAppName[] = TEXT ("RandRect") ;

       HWND           hwnd ;

       MSG              msg ;

       WNDCLASS  wndclass ;

    int i;

    

       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 ;

       if (!RegisterClass (&wndclass))

       {

              MessageBox (NULL, TEXT ("This program requires Windows NT!"),

                                   szAppName, MB_ICONERROR) ;

              return 0 ;

       }

    

       hwnd = CreateWindow (       szAppName, TEXT ("Random Rectangles"),

                            WS_OVERLAPPEDWINDOW,

                            CW_USEDEFAULT, CW_USEDEFAULT,

                            CW_USEDEFAULT, CW_USEDEFAULT,

                            NULL, NULL, hInstance, NULL) ;

    

       ShowWindow (hwnd, iCmdShow) ;

       UpdateWindow (hwnd) ;

    

       while (TRUE)

       {

              if (PeekMessage (&msg, NULL, 0, 0, PM_REMOVE))

              {

                     if (msg.message == WM_QUIT)

                        break ;

                     TranslateMessage (&msg) ;

                     DispatchMessage (&msg) ;

          }

              else
     {
         for(i=0; i<10000000; i++);
     
                     DrawRectangle (hwnd) ;

      for(i=0; i<10000000; i++);
              }
       }

       return msg.wParam ;

}

 

LRESULT CALLBACK WndProc (HWND hwnd, UINT iMsg, WPARAM wParam, LPARAM lParam)

{

       switch (iMsg)

       {

       case WM_SIZE:

              cxClient = LOWORD (lParam) ;

              cyClient = HIWORD (lParam) ;

              return 0 ;

         

       case WM_DESTROY:

              PostQuitMessage (0) ;

              return 0 ;

       }

       return DefWindowProc (hwnd, iMsg, wParam, lParam) ;

}

void DrawRectangle (HWND hwnd)

{

       HBRUSH hBrush ;

       HDC             hdc ;

       RECT            rect ;

    

       if (cxClient == 0 || cyClient == 0)

              return ;

       SetRect (&rect, rand () % cxClient, rand () % cyClient,

                            rand () % cxClient, rand () % cyClient) ;

       hBrush = CreateSolidBrush (

                     RGB (rand () % 256, rand () % 256, rand () % 256)) ;

       hdc = GetDC (hwnd) ;

       FillRect (hdc, &rect, hBrush) ;

       ReleaseDC (hwnd, hdc) ;

       DeleteObject (hBrush) ;

}