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## 1. 实现截图程序的api接口 ##
HBITMAP CaptureScreen(LPRECT lpRect)//lpRect为NULL时表示全屏幕截图
{HDC hdc, hdcMem ;HBITMAP hemfCopy ;HWND hwndScr ;int dstcx, dstcy ;if(lpRect){dstcx = lpRect->right - lpRect->left ;dstcy = lpRect->bottom - lpRect->top ;}else{dstcx = GetSystemMetrics(SM_CXSCREEN) ;dstcy = GetSystemMetrics(SM_CYSCREEN) ;}if (LockWindowUpdate(hwndScr = GetDesktopWindow ())){hdc = GetDCEx (hwndScr, NULL, DCX_CACHE | DCX_LOCKWINDOWUPDATE) ;hdcMem = CreateCompatibleDC (hdc) ;if(NULL==hdcMem){ReleaseDC (hwndScr, hdc) ;LockWindowUpdate (NULL) ;return NULL;}hemfCopy = CreateCompatibleBitmap (hdc, abs(dstcx), abs(dstcy)) ;if(NULL==hemfCopy){DeleteDC (hdcMem) ;ReleaseDC (hwndScr, hdc) ;LockWindowUpdate (NULL) ;return NULL;}SelectObject (hdcMem, hemfCopy) ;if(lpRect)StretchBlt (hdcMem, 0, 0, abs(dstcx), abs(dstcy), hdc, lpRect->left, lpRect->top, dstcx, dstcy, SRCCOPY|CAPTUREBLT) ;elseBitBlt (hdcMem, 0, 0, dstcx, dstcy, hdc, 0, 0, SRCCOPY|CAPTUREBLT) ;DeleteDC (hdcMem) ;ReleaseDC (hwndScr, hdc) ;LockWindowUpdate (NULL) ;return hemfCopy;}return NULL;
}
``2、保存图片
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(TEXT("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;
} 3、在dialog中 显示
在onPaint中显示 ，其中mfc设计到 BITMAP hbitmap和cbitmap之间的关系
在mfc程序中，使用cbitmap
CPaintDC dc(this);CDC dcimage;CBitmap bkg;bkg.Attach(g_bitmap);BITMAP bkginfo;bkg.GetBitmap(&bkginfo);//获取位图信息dcimage.CreateCompatibleDC(&dc);dcimage.SelectObject(&bkg);// dc.BitBlt(0,0,nWidth,nHeight,&dcimage,0,0,SRCCOPY);dc.StretchBlt(0,0,nWidth,nHeight,&dcimage,0,0,bkginfo.bmWidth,bkginfo.bmHeight,SRCCOPY);`
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