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Title: Window Region example


Xception - July 9, 2003 12:26 PM (GMT)
compile as Win32 Gui project
CODE
// Window Region example
// created by Xception
// press any key to quit

#include <windows.h>

/*  Declare Windows procedure  */
LRESULT CALLBACK WindowProcedure (HWND, UINT, WPARAM, LPARAM);

/*  Make the class name into a global variable  */
char szClassName[ ] = "WindowsApp";

int WINAPI
WinMain (HINSTANCE hThisInstance,
        HINSTANCE hPrevInstance,
        LPSTR lpszArgument,
        int nFunsterStil)

{
   HWND hwnd;               /* This is the handle for our window */
   MSG messages;            /* Here messages to the application are saved */
   WNDCLASSEX wincl;        /* Data structure for the windowclass */

   /* The Window structure */
   wincl.hInstance = hThisInstance;
   wincl.lpszClassName = szClassName;
   wincl.lpfnWndProc = WindowProcedure;      /* This function is called by windows */
   wincl.style = CS_DBLCLKS;                 /* Catch double-clicks */
   wincl.cbSize = sizeof (WNDCLASSEX);

   /* Use default icon and mouse-pointer */
   wincl.hIcon = LoadIcon (NULL, IDI_APPLICATION);
   wincl.hIconSm = LoadIcon (NULL, IDI_APPLICATION);
   wincl.hCursor = LoadCursor (NULL, IDC_ARROW);
   wincl.lpszMenuName = NULL;                 /* No menu */
   wincl.cbClsExtra = 0;                      /* No extra bytes after the window class */
   wincl.cbWndExtra = 0;                      /* structure or the window instance */
   /* Use Windows's default color as the background of the window */
   wincl.hbrBackground = (HBRUSH) COLOR_BACKGROUND;

   /* Register the window class, and if it fails quit the program */
   if (!RegisterClassEx (&wincl))
       return 0;

   /* The class is registered, let's create the program*/
   hwnd = CreateWindowEx (
          0,                   /* Extended possibilites for variation */
          szClassName,         /* Classname */
          "Windows App",       /* Title Text */
          WS_OVERLAPPEDWINDOW, /* default window */
          CW_USEDEFAULT,       /* Windows decides the position */
          CW_USEDEFAULT,       /* where the window ends up on the screen */
          400,                 /* The programs width */
          300,                 /* and height in pixels */
          HWND_DESKTOP,        /* The window is a child-window to desktop */
          NULL,                /* No menu */
          hThisInstance,       /* Program Instance handler */
          NULL                 /* No Window Creation data */
          );

   /* Make the window visible on the screen */
   ShowWindow (hwnd, nFunsterStil);
   
// **** Regions, uncomment and comment uncommented for another example  
  // HRGN rgn=CreateEllipticRgn(0,0,400,300);
   HRGN rgn=CreateEllipticRgn(100,0,350,250);
 //  HRGN rgn=CreateRoundRectRgn(20,20,380,280,25,25);
   SetWindowRgn(hwnd,rgn,true);
   DeleteObject(rgn);
   /* Run the message loop. It will run until GetMessage() returns 0 */
   while (GetMessage (&messages, NULL, 0, 0))
   {
       /* Translate virtual-key messages into character messages */
       TranslateMessage(&messages);
       /* Send message to WindowProcedure */
       DispatchMessage(&messages);
   }

   /* The program return-value is 0 - The value that PostQuitMessage() gave */
   return messages.wParam;
}

/*  This function is called by the Windows function DispatchMessage()  */

LRESULT CALLBACK
WindowProcedure (HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
   switch (message)                  /* handle the messages */
   {   case WM_KEYDOWN:
           
       case WM_DESTROY:
           PostQuitMessage (0);       /* send a WM_QUIT to the message queue */
           break;
       default:                      /* for messages that we don't deal with */
           return DefWindowProc (hwnd, message, wParam, lParam);
   }

   return 0;
}

Dragon - July 9, 2003 07:57 PM (GMT)
That's pretty cool Xception. But why is the window a child to the desktop? Also, for class name you used szClassName. In some other examples they use g_szClassName. Does the 'g' just stand for global or does it do something else? There is also 'const char', instead of just 'char'. Does it really matter?

Xception - July 9, 2003 08:30 PM (GMT)
I used the Dev-c++ template and added only some lines. I guess g stands for global, but you can call it what you want and because you don't change the classname you can use a constant, I usually don't use a variable at all for the classname.




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