截取屏幕指定区域保存为BMP文件

HBITMAP CopyScreenToBitmap(LPRECT lpRect){//屏幕和内存设备描述表HDC hSrcDC, hMemDC;//位图句柄HBITMAP hBitmap, hOldBitmap;//选定区域坐标int nX, nY, nX2, nY2;//位图宽度和高度int nWidth, nHeight;//屏幕分辨率int xScrn, yScrn;//确保选定区域不为空矩形if(IsRectEmpty(lpRect))return NULL;//为屏幕创建设备描述表hSrcDC = CreateDC("DISPLAY", NULL, NULL, NULL);//为屏幕设备描述表创建兼容的内存设备描述表hMemDC = CreateCompatibleDC(hSrcDC);//获得选定区域坐标nX ＝ lpRect->left;nY = lpRect->top;nX2 = lpRect->right;nY2 = lpRect->bottom;//获得屏幕分辨率xScrn = GetDeviceCaps(hSrcDC, HORZRES);yScrn = GetDeviceCaps(hSrcDC, VERTRES);//确保选定区域是可见的if(nX<0)nX = 0;if(nY<0)nY = 0;if(nX2>xScrn)nX2 = xScrn;if(nY2>yScrn)nY2 = yScrn;nWidth = nX2 - nX;nHeight = nY2 - nY;//创建一个与屏幕设备描述表兼容的位图hBitmap = CreateCompatibleBitmap(hSrcDC, nWidth, nHeight);//把新位图选到内存设备描述表中hOldBitmap = (HBITMAP)SelectObject(hMemDC, hBitmap);//把屏幕设备描述表拷贝到内存设备描述表中BitBlt(hMemDC, 0, 0, nWidth, nHeight, hSrcDC, nX, nY, SRCCOPY);//得到屏幕位图的句柄hBitmap = (HBITMAP)SelectObject(hMemDC, hOldBitmap);//清除DeleteDC(hSrcDC);DeleteDC(hMemDC);//返回位置句柄}*/HBITMAP CopyScreenToBitmap(int x1, int x2, int y1, int y2){//屏幕和内存设备描述表HDC hSrcDC, hMemDC;//位图句柄HBITMAP hBitmap, hOldBitmap;//选定区域坐标int nX, nY, nX2, nY2;//位图宽度和高度int nWidth, nHeight;//屏幕分辨率int xScrn, yScrn;/*//确保选定区域不为空矩形if(IsRectEmpty(lpRect))return NULL;*///为屏幕创建设备描述表hSrcDC = CreateDC("DISPLAY", NULL, NULL, NULL);//为屏幕设备描述表创建兼容的内存设备描述表hMemDC = CreateCompatibleDC(hSrcDC);//获得选定区域坐标nX = x1;nY = y1;nX2 = x2;nY2 = y2;//获得屏幕分辨率xScrn = GetDeviceCaps(hSrcDC, HORZRES);yScrn = GetDeviceCaps(hSrcDC, VERTRES);//确保选定区域是可见的if(nX<0)nX = 0;if(nY<0)nY = 0;if(nX2>xScrn)nX2 = xScrn;if(nY2>yScrn)nY2 = yScrn;nWidth = nX2 - nX;nHeight = nY2 - nY;//创建一个与屏幕设备描述表兼容的位图hBitmap = CreateCompatibleBitmap(hSrcDC, nWidth, nHeight);//把新位图选到内存设备描述表中hOldBitmap = (HBITMAP)SelectObject(hMemDC, hBitmap);//把屏幕设备描述表拷贝到内存设备描述表中BitBlt(hMemDC, 0, 0, nWidth, nHeight, hSrcDC, nX, nY, SRCCOPY);//得到屏幕位图的句柄hBitmap = (HBITMAP)SelectObject(hMemDC, hOldBitmap);//清除DeleteDC(hSrcDC);DeleteDC(hMemDC);//返回位置句柄return hBitmap;}BOOL SaveCapturedBitmap(HBITMAP hBitmap, CString FileName){if(hBitmap==NULL || FileName.IsEmpty()){AfxMessageBox("参数错误");return false;}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;elsewBitCount = 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;}int main(){HBITMAP hCaptureBitmap = CopyScreenToBitmap(100, 700, 100, 700);SaveCapturedBitmap(hCaptureBitmap, "Hello.bmp");return 0;}