Use GDI + to save HDC as a bitmap file

// GDI + is used to load and store images. It shields the details of internal codec, compression, and decompression. Program Personnel bring great convenience // the current version of GDI + supports bmp jpeg gif tiff PNG and other formats // The basic idea of the following program is to first save the content on the Target DC to the memory bitmap // use GDI + bitmap again:: fromhbitmap loads the memory bitmap and saves it as a file. // This version is tested in Win32 and MFC environments. /// use GDI + to save HDC as a bitmap file # include <RPC. h> # include <rpcndr. h> # include <unknwn. h> # include <gdiplus. h> using namespace gdiplus; # pragma comment (Lib, "gdiplus. lib ") struct _ gdiplustoken {gdiplus: gdiplusstartupinput; ulong_ptr gdiplustoken; _ gdiplus Token () {If (gdiplus: gdiplusstartup (& gdiplustoken, & gdiplusstartupinput, null )! = OK) {MessageBox (null, _ T ("gdiplusstartup failed"), _ T ("error"), mb_ OK );}}~ _ Gdiplustoken () {gdiplus: gdiplusshutdown (gdiplustoken) ;}} gdiplustoken; int getencoderclsid (const wchar * format, CLSID * pclsid) {uint num = 0; // Number of image encoders uint size = 0; // size of the image encoder array in bytes imagecodecinfo * pimagecodecinfo = NULL; gdiplus: getimageencoderssize (& num, & size ); if (size = 0) Return-1; // failure pimagecodecinfo = (imagecodecinfo *) (malloc (size); If (pimagecodecinfo = NULL) Return-1; // failure gdiplus: getimageencoders (Num, size, pimagecodecinfo); For (uint J = 0; j <num; ++ J) {If (wcscmp (pimagecodecinfo [J]. mimetype, format) = 0) {* pclsid = pimagecodecinfo [J]. CLSID; free (pimagecodecinfo); Return J; // success} Free (pimagecodecinfo); Return-1; // failure} bool savehdctofile (HDC, lprect) {bool Bret = false; int nwidth = lprect-> right-lprect-> left; int nheight = lprect-> bottom-lprect-> top; // map the target region to the memory bitmap HDC memdc = createcompatibledc (HDC); hbitmap hbmp = createcompatiblebitmap (HDC, nwidth, nheight); SelectObject (memdc, hbmp); bitblt (memdc, lprect-> left, lprect-> top, nwidth, nheight, HDC, 0, 0, srccopy ); // save it as a file {// L "image/BMP" L "image/JPEG" L "image/GIF" L "image/tiff" L "image/PNG" CLSID pngclsid; getencoderclsid (L "image/BMP", & pngclsid); // take BMP as an example. Select the corresponding type for other formats, for example, JPG uses l "image/JPEG" gdiplus :: bitmap * pbmsrc = gdiplus: bitmap: fromhbitmap (hbmp, null); If (pbmsrc-> Save (L "C: \ test.bmp", & pngclsid) = OK) {Bret = true;} Delete pbmsrc;} // cleanup SelectObject (memdc, (hbitmap) null); deletedc (memdc); deleteobject (hbmp); Return Bret ;}

 

 

 
// Test case lresult callback wndproc (hwnd, uint message, wparam, lparam) {int wmid, wmevent; paintstruct pS; HDC; Switch (Message) {Case wm_paint: HDC = beginpaint (hwnd, & PS); // todo: add any drawing hereCode... Textout (HDC, 0, 0, _ T ("ABCD"), 4); endpaint (hwnd, & PS); break; Case wm_keydown: {HDC = getdc (hwnd); rect rcrect; getclientrect (hwnd, & rcrect); savehdctofile (HDC, & rcrect); releasedc (hwnd, HDC); break ;} case wm_destroy: postquitmessage (0); break; default: Return defwindowproc (hwnd, message, wparam, lparam);} return 0 ;}