stretch.c

C#一个实例源代码

/*-----------------------------------------
   Stretch.c
  -----------------------------------------*/

#include <windows.h>

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

int WINAPI WinMain (HINSTANCE hInstance, HINSTANCE hPrevInstance,
                    PSTR szCmdLine, int iCmdShow)
{
     static TCHAR szAppName [] = TEXT ("Stretch") ;
     HWND         hwnd ;
     MSG          msg ;
     WNDCLASS     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  = szAppName ;
     wndclass.lpszClassName = szAppName ;
     
     if (!RegisterClass (&wndclass))
     {
          MessageBox (NULL, TEXT ("This program requires Windows NT!"),
                      szAppName, MB_ICONERROR) ;
          return 0 ;
     }
     
     hwnd = CreateWindow (szAppName, TEXT ("Stretch"), 
                          WS_OVERLAPPEDWINDOW, 
                          CW_USEDEFAULT, CW_USEDEFAULT,
                          CW_USEDEFAULT, CW_USEDEFAULT,
                          NULL, NULL, hInstance, NULL) ;

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

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

LRESULT CALLBACK WndProc (HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
     static HBITMAP hBitmap ;
     static HDC     hdcMem ;
     static int     cxBitmap, cyBitmap, cxClient, cyClient;
     static TCHAR * szText = TEXT (" Hello, Bitmap! ") ;
     HDC            hdc ;
     PAINTSTRUCT    ps ;
     SIZE           size ;
     
     switch (message)
     {
     case WM_CREATE:
          hdc = GetDC (hwnd) ;
          hdcMem  = CreateCompatibleDC (hdc) ;

          GetTextExtentPoint32 (hdc, szText, lstrlen (szText), &size) ;
          cxBitmap = size.cx ;
          cyBitmap = size.cy ;
          hBitmap = CreateCompatibleBitmap (hdc, cxBitmap, cyBitmap) ;

          ReleaseDC (hwnd, hdc) ;

          SelectObject (hdcMem, hBitmap) ;
          TextOut (hdcMem, 0, 0, szText, lstrlen (szText)) ;
          return 0 ;

     case WM_SIZE:
          cxClient = LOWORD (lParam) ;
          cyClient = HIWORD (lParam) ;
          return 0 ;

     

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

         
               StretchBlt (hdc, 0, 0, cxClient, cyClient, 
                           hdcMem, 0, 0, cxBitmap, cyBitmap, SRCCOPY) ;
         

          EndPaint (hwnd, &ps) ;
          return 0 ;

     case WM_DESTROY:
          DeleteDC (hdcMem) ;
          DeleteObject (hBitmap) ;
          PostQuitMessage (0) ;
          return 0 ;
     }
     return DefWindowProc (hwnd, message, wParam, lParam) ;
}