HBITMAP CaptureScreen(void)
{
   HWND hDesktopWnd;
   HDC hDesktopDC,hCaptureDC;
   HBITMAP hCaptureBitmap;
   // Ricavo la risoluzione dello schermo
   int nScreenWidth = GetSystemMetrics(SM_CXSCREEN);
   int nScreenHeight = GetSystemMetrics(SM_CYSCREEN);
 
   // Aquisizione handle finestra Desktop
   hDesktopWnd = GetDesktopWindow();	
   // Ricavo il DC della finestra
   hDesktopDC = GetDC(hDesktopWnd);
   // Creo un DC in memoria compatibile con la finestra catturata
   hCaptureDC = CreateCompatibleDC(hDesktopDC);
   // Creo una bitmap compatibile associata al DC della finestra catturata
   hCaptureBitmap = CreateCompatibleBitmap(hDesktopDC, 
                                           nScreenWidth,
                                           nScreenHeight);
   // Seleziono l'immagine dal DC
   SelectObject(hCaptureDC,hCaptureBitmap); 
   // Trasferisco il contenuto del DC catturato nel DC comptabile creato
   BitBlt(hCaptureDC,0,0,nScreenWidth,nScreenHeight,hDesktopDC,0,0,SRCCOPY); 
 
   // Rilascio il DC della finestra
   ReleaseDC(hDesktopWnd,hDesktopDC);
   // Cancello il DC compatibile
   DeleteDC(hCaptureDC);
 
   // Ritorno l'handle della bitmap
   return hCaptureBitmap;
}

BOOL SaveCapturedBitmap(char* FilePath,HBITMAP hBitmap)
{
   HDC   hdc = NULL;
   FILE* fp  = NULL;
   LPVOID pBuf = NULL;
   BITMAPINFO bmpInfo;
   BITMAPFILEHEADER  bmpFileHeader; 
   hdc=GetDC(NULL);
   ZeroMemory(&bmpInfo,sizeof(BITMAPINFO));
   bmpInfo.bmiHeader.biSize=sizeof(BITMAPINFOHEADER);
   GetDIBits(hdc,hBitmap,0,0,NULL,&bmpInfo,DIB_RGB_COLORS); 
 
   if (bmpInfo.bmiHeader.biSizeImage<=0)
      bmpInfo.bmiHeader.biSizeImage = bmpInfo.bmiHeader.biWidth*
                                    abs(bmpInfo.bmiHeader.biHeight)*
                                    (bmpInfo.bmiHeader.biBitCount+7)/8;
 
   if ((pBuf = malloc(bmpInfo.bmiHeader.biSizeImage))==NULL)
   {
      //printf("Unable to Allocate Bitmap Memory");
      return false;
   }           
 
   bmpInfo.bmiHeader.biCompression=BI_RGB;
   GetDIBits(hdc,
             hBitmap,
             0,
             bmpInfo.bmiHeader.biHeight,
             pBuf, 
             &bmpInfo, 
             DIB_RGB_COLORS);       
 
   if((fp = fopen(FilePath,"wb"))==NULL)
   {
      //printf("Unable to Create Bitmap File");
      return false;
   } 
 
   bmpFileHeader.bfReserved1=0;
   bmpFileHeader.bfReserved2=0;
   bmpFileHeader.bfSize=sizeof(BITMAPFILEHEADER)+
                        sizeof(BITMAPINFOHEADER)+
                        bmpInfo.bmiHeader.biSizeImage;
   bmpFileHeader.bfType='MB';
   bmpFileHeader.bfOffBits=sizeof(BITMAPFILEHEADER)+
                           sizeof(BITMAPINFOHEADER); 
   fwrite(&bmpFileHeader,sizeof(BITMAPFILEHEADER),1,fp);
   fwrite(&bmpInfo.bmiHeader,sizeof(BITMAPINFOHEADER),1,fp);
   fwrite(pBuf,bmpInfo.bmiHeader.biSizeImage,1,fp); 
   fclose(fp);
 
   return true;
}

BOOL SaveCapturedJpeg(char* FilePath,HBITMAP hBitmap)
{
   CxImage image;
 
   image.CreateFromHBITMAP(hBitmap);				
 
   if (image.IsValid())
      image.Save(FilePath,CXIMAGE_FORMAT_JPG);
   else
      return false;
 
   return true;
}

#pragma comment(linker,"/subsystem:windows")
#pragma comment(linker,"/NODEFAULTLIB:LIBC.LIB")
 
#include "Screen.h"
 
 
int WINAPI WinMain(HINSTANCE hInstance,
                   HINSTANCE hPrevInstance,LPSTR lpCmdLine, int nCmdShow) 
{
	HBITMAP hCaptureBitmap;
 
	// Catturo la schermata
	hCaptureBitmap = CaptureScreen();
	// Ne salvo una copia in formato bitmap
	SaveCapturedBitmap("c:\screen.bmp",hCaptureBitmap);
	// Ne salvo una copia in formato jpeg
	SaveCapturedJpeg("c:\screen.jpg",hCaptureBitmap); 
 
	// Rilascio
	DeleteObject(hCaptureBitmap);
 
	return 0;
}