int SaveBitmapToFile(HBITMAP hBitmap, LPSTR lpFileName)
{
//我们也可以把屏幕内容以位图格式存到磁盘文件上.
//lpFileName 为位图文件名
HDC hDC; //设备描述表
int iBits; //当前显示分辨率下每个像素所占字节数
WORD wBitCount; //位图中每个像素所占字节数
//定义调色板大小, 位图中像素字节大小,位图文件大小,写入文件字节数
DWORD dwPaletteSize=0,
dwBmBitsSize,
dwDIBSize, dwWritten;
BITMAP Bitmap; //位图属性结构
BITMAPFILEHEADER bmfHdr; //位图文件头结构
BITMAPINFOHEADER bi; //位图信息头结构
LPBITMAPINFOHEADER lpbi; //指向位图信息头结构
HANDLE fh, hDib, hPal,hOldPal=NULL;
//定义文件,分配内存句柄,调色板句柄
//计算位图文件每个像素所占字节数
hDC = CreateDC("DISPLAY",NULL,NULL,NULL);
iBits = GetDeviceCaps(hDC, BITSPIXEL)*GetDeviceCaps(hDC, PLANES);
DeleteDC(hDC);
if (iBits <= 1)
wBitCount = 1;
else if (iBits <= 4)
wBitCount = 4;
else if (iBits <= 8)
wBitCount = 8;
else if (iBits <= 32)
wBitCount = 24;
//计算调色板大小
if (wBitCount <= 8)
dwPaletteSize = (1 << wBitCount) *
sizeof(RGBQUAD);
//设置位图信息头结构
GetObject(hBitmap, sizeof(BITMAP), (LPSTR)&Bitmap);
bi.biSize = sizeof(BITMAPINFOHEADER);
bi.biWidth = Bitmap.bmWidth;
bi.biHeight = Bitmap.bmHeight;
bi.biPlanes = 1;
bi.biBitCount = wBitCount;
bi.biCompression = BI_RGB;
bi.biSizeImage = 0;
bi.biXPelsPerMeter = 0;
bi.biYPelsPerMeter = 0;
bi.biClrUsed = 0;
bi.biClrImportant = 0;
dwBmBitsSize = ((Bitmap.bmWidth*wBitCount+31)/32)* 4*Bitmap.bmHeight ;
hDib = GlobalAlloc(GHND,dwBmBitsSize+dwPaletteSize+sizeof(BITMAPINFOHEADER));//为位图内容分配内存
lpbi = (LPBITMAPINFOHEADER)GlobalLock(hDib);
*lpbi = bi;
hPal=(HPALETTE)::GetStockObject(DEFAULT_PALETTE);// 处理调色板
if (hPal)
{
hDC = GetDC(NULL);
hOldPal = SelectPalette(hDC,(HPALETTE)hPal, FALSE);
RealizePalette(hDC);
}
// 获取该调色板下新的像素值
GetDIBits(hDC, hBitmap, 0, (UINT) Bitmap.bmHeight,
(LPSTR)lpbi + sizeof(BITMAPINFOHEADER)
+dwPaletteSize,
(BITMAPINFO *)
lpbi, DIB_RGB_COLORS);
//恢复调色板
if (hOldPal)
{
SelectPalette(hDC,(HPALETTE) hOldPal, TRUE);
RealizePalette(hDC);
ReleaseDC(NULL, hDC);
}
//创建位图文件
fh = CreateFile(lpFileName, GENERIC_WRITE,0, NULL, CREATE_ALWAYS,
FILE_ATTRIBUTE_NORMAL|FILE_FLAG_SEQUENTIAL_SCAN, NULL);
if (fh == INVALID_HANDLE_VALUE)
return FALSE;
// 设置位图文件头
bmfHdr.bfType = 0x4D42; // "BM"
dwDIBSize = sizeof(BITMAPFILEHEADER)+sizeof(BITMAPINFOHEADER)
+ dwPaletteSize + dwBmBitsSize;
bmfHdr.bfSize = dwDIBSize;
bmfHdr.bfReserved1 = 0;
bmfHdr.bfReserved2 = 0;
bmfHdr.bfOffBits = (DWORD)sizeof
(BITMAPFILEHEADER)
+ (DWORD)sizeof(BITMAPINFOHEADER)
+ dwPaletteSize;
// 写入位图文件头
WriteFile(fh, (LPSTR)&bmfHdr, sizeof
(BITMAPFILEHEADER), &dwWritten, NULL);
// 写入位图文件其余内容
WriteFile(fh, (LPSTR)lpbi, dwDIBSize,
&dwWritten, NULL);
//清除
GlobalUnlock(hDib);
GlobalFree(hDib);
CloseHandle(fh);
return TRUE;
}
void CTestDlg::OnBnClickedButton1()
{
//设定截图区域的宽高..
int width = 1024,
height = 768;
//设定所要截取窗口的句柄, 此处是获取桌面窗口.
HDC hDC = ::GetDC( ::GetDesktopWindow());
//
HDC hComDC=CreateCompatibleDC(hDC);
HBITMAP hBmp = CreateCompatibleBitmap(hDC,width,height);
HBITMAP hOldBmp = (HBITMAP)SelectObject(hComDC,hBmp);
BitBlt( hComDC,0,0,width,height,hDC,0,0,SRCCOPY );
SelectObject( hComDC,hOldBmp );
DeleteDC( hDC );
SaveBitmapToFile( hBmp, "c:\\a.bmp" );
DeleteObject(hBmp);
}