PrintWindow这个函数只可以在XP以上使用,并且在VC6上使用稍有不同。具体请参照下面代码。下面代码基于VC6编译且通过。

#include "stdafx.h"#include <stdio.h>#include <afxwin.h>BOOL SaveBmp(HBITMAP hBitmap, CString FileName) { HDC hDC; //当前分辨率下每象素所占字节数 int iBits; //位图中每象素所占字节数 WORD wBitCount; //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=0, dwDIBSize=0, dwWritten=0; //位图属性结构 BITMAP Bitmap; //位图文件头结构 BITMAPFILEHEADER bmfHdr; //位图信息头结构 BITMAPINFOHEADER bi; //指向位图信息头结构 LPBITMAPINFOHEADER lpbi; //定义文件,分配内存句柄,调色板句柄 HANDLE fh, hDib, hPal,hOldPal=NULL; //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 wBitCount = 24; 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.biClrImportant = 0; bi.biClrUsed = 0; dwBmBitsSize = ((Bitmap.bmWidth *wBitCount+31) / 32)*4* Bitmap.bmHeight; //为位图内容分配内存 hDib = GlobalAlloc(GHND,dwBmBitsSize+dwPaletteSize+sizeof(BITMAPINFOHEADER)); lpbi = (LPBITMAPINFOHEADER)GlobalLock(hDib); *lpbi = bi; // 处理调色板 hPal = GetStockObject(DEFAULT_PALETTE); 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(FileName, 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; } HBITMAP GetWindowBitmap(HWND hWnd){ typedef BOOL ( __stdcall *pPrintWindow )(HWND hWnd,HDC hdcBlt,UINT nFlags); RECT rect; HMODULE h; h = LoadLibrary( "user32.dll" ); pPrintWindow p; if( h ) { p = ( pPrintWindow )::GetProcAddress( h, "PrintWindow" ); } ::GetWindowRect(hWnd,&rect); HDC hScrDC=::GetDC(hWnd); //创建屏幕DC HDC hMemDC=CreateCompatibleDC(hScrDC); //创建内存DC HBITMAP bitmap=::CreateCompatibleBitmap(hScrDC,rect.right-rect.left,rect.bottom-rect.top); //创建兼容位图 HBITMAP OldBitmap=(HBITMAP)::SelectObject(hMemDC,bitmap); //把位图选进内存DC p(hWnd,hMemDC,0); // HDC d;// HWND hw;// hw = ::GetDesktopWindow();// d = ::GetWindowDC( hw );// ::BitBlt( d, 0, 0, 1200, 1200, hMemDC, 0, 0, SRCCOPY ); ::SelectObject(hMemDC,OldBitmap); ::DeleteDC(hMemDC) ; //删除内存DC ::ReleaseDC(NULL,hScrDC) ; //释放屏幕DC SaveBmp(bitmap,"D:\\calc.jpg"); return bitmap;}int main(int argc, char* argv[]){ //if(argc<2){printf("缺少参数。");return 0;} HWND calc; calc=::FindWindow(NULL,"计算器"); GetWindowBitmap(calc); getchar(); return 0;}