#include<windows.h>

HANDLE DDBtoDIB( HBITMAP bitmap, DWORD dwCompression, HPALETTE  hPal,DWORD * sizeimage) ;
BOOL CapScreen(LPTSTR FileName);//截屏函數

HANDLE DDBtoDIB( HBITMAP bitmap, DWORD dwCompression, HPALETTE  hPal,DWORD * sizeimage) 
{
    BITMAP            bm;
    BITMAPINFOHEADER    bi;
     LPBITMAPINFOHEADER     lpbi;
    DWORD            dwLen;
    HANDLE            hDib;
    HANDLE            handle;
    HDC             hdc;

    //不支持BI_BITFIELDS類型
    if( dwCompression == BI_BITFIELDS )
        return NULL;

    //如果調色板為空，則用默認調色板
    if (hPal==NULL)
        hPal = (HPALETTE) GetStockObject(DEFAULT_PALETTE );

    //獲取位圖信息
    GetObject(bitmap,sizeof(bm),(LPSTR)&bm);

    //初始化位圖信息頭
    bi.biSize        = sizeof(BITMAPINFOHEADER);
    bi.biWidth        = bm.bmWidth;
    bi.biHeight         = bm.bmHeight;
    bi.biPlanes         = 1;
    bi.biBitCount        = bm.bmPlanes * bm.bmBitsPixel;
    bi.biCompression    = dwCompression;
    bi.biSizeImage        = 0;
    bi.biXPelsPerMeter    = 0;
    bi.biYPelsPerMeter    = 0;
    bi.biClrUsed        = 0;
    bi.biClrImportant    = 0;

    //計算信息頭及顏色表大小
    int ncolors = (1 << bi.biBitCount); if( ncolors> 256 ) 
        ncolors = 0;
    dwLen  = bi.biSize + ncolors * sizeof(RGBQUAD);

    // we need a device context to get the dib from
    hdc = GetDC(NULL);
    hPal = SelectPalette(hdc,hPal,FALSE);
    RealizePalette(hdc);

    //為信息頭及顏色表分配內存
    hDib = GlobalAlloc(GMEM_FIXED,dwLen);

    if (!hDib){
        SelectPalette(hdc,hPal,FALSE);
        ReleaseDC(NULL,hdc);
        return NULL;
    }

    lpbi = (LPBITMAPINFOHEADER)hDib;
    *lpbi = bi;
    //調用 GetDIBits 計算圖像大小
    GetDIBits(hdc, bitmap, 0L, (DWORD)bi.biHeight,
            (LPBYTE)NULL, (LPBITMAPINFO)lpbi, (DWORD)DIB_RGB_COLORS );

    bi = *lpbi;
    //圖像的每一行都對齊(32bit)邊界
	if (bi.biSizeImage == 0){
        bi.biSizeImage = ((((bi.biWidth * bi.biBitCount) + 31) & ~31) / 8) 
                        * bi.biHeight;
    if (dwCompression != BI_RGB)
            bi.biSizeImage = (bi.biSizeImage * 3) / 2;
    }

    //重新分配內存大小，以便放下所有數據
    dwLen += bi.biSizeImage;
    if (handle = GlobalReAlloc(hDib, dwLen, GMEM_MOVEABLE))
        hDib = handle;
    else{
        GlobalFree(hDib);

        //重選原始調色板
        SelectPalette(hdc,hPal,FALSE);
        ReleaseDC(NULL,hdc);
        return NULL;
    }

    //獲取位圖數據
    lpbi = (LPBITMAPINFOHEADER)hDib;

    //最終獲得的DIB
    BOOL bgotbits = GetDIBits( hdc, bitmap,
                  0L,                      //掃描行起始處
                (DWORD)bi.biHeight,      //掃描行數
                (LPBYTE)lpbi             //位圖數據地址
                + (bi.biSize + ncolors * sizeof(RGBQUAD)),
                (LPBITMAPINFO)lpbi,      //位圖信息地址
                (DWORD)DIB_RGB_COLORS);  //顏色板使用RGB

    if( !bgotbits )
    {
        GlobalFree(hDib);
        
        SelectPalette(hdc,hPal,FALSE);
        ReleaseDC(NULL,hdc);
		return NULL;
    }

    SelectPalette(hdc,hPal,FALSE);
    ReleaseDC(NULL,hdc);
	*sizeimage=bi.biSizeImage;
    return hDib;
} 

BOOL CapScreen(LPTSTR FileName)
{
	DWORD sizeimage;
	HDC hdc = CreateDC("DISPLAY", NULL, NULL, NULL); 
	HDC CompatibleHDC = CreateCompatibleDC(hdc); 
	HBITMAP BmpScreen = CreateCompatibleBitmap(hdc,GetDeviceCaps(hdc, HORZRES),GetDeviceCaps(hdc, VERTRES)); 
	SelectObject(CompatibleHDC, BmpScreen);
	BitBlt(CompatibleHDC,0,0,GetDeviceCaps(hdc, HORZRES), GetDeviceCaps(hdc, VERTRES),hdc,0,0,SRCCOPY);
	
HANDLE	pbitmapwithoutfileh=DDBtoDIB(BmpScreen, BI_RGB,0,&sizeimage);
	BITMAPFILEHEADER bfh;
   //設置位圖信息頭結構
	bfh.bfType = ((WORD)('M'<< 8)|'B');
	bfh.bfReserved1 = 0;
	bfh.bfReserved2 = 0;
	bfh.bfSize = 54+sizeimage;
	bfh.bfOffBits = 54;
	//創建位圖文件    
HANDLE  hFile=CreateFile(FileName,GENERIC_WRITE,0,0,CREATE_ALWAYS,FILE_ATTRIBUTE_NORMAL,0);
DWORD dwWrite;
// 寫入位圖文件頭
WriteFile(hFile,&bfh,sizeof(BITMAPFILEHEADER),&dwWrite,NULL);
// 寫入位圖文件其余內容
WriteFile(hFile,pbitmapwithoutfileh,bfh.bfSize,&dwWrite,NULL);  
DeleteDC(hdc);
   
CloseHandle(CompatibleHDC);
return true;
}

int main(void)
{
CapScreen("d:\\desktop.bmp");
return 0;
}