Memory ing for inter-process communication

The example uses memory ing to load the BMP bitmap from the server to the memory, and the client reads and displays it from the memory.

// Part of the server code void cserverdlg: oncreatefilemap () {// todo: add your control notification handler code herecbutton * pbutton = (cbutton *) getdlgitem (idc_button1 ); pbutton-> enablewindow (false); cstring filename = _ T ("image \ 3.bmp"); // 1. load the file m_hfile = createfile (filename, generic_read, file_share_read, null, open_existing, file_attribute_normal, null); If (m_hfile = invalid_handle_value) {MessageBox (_ T ("file loading failed !!! "), Null, mb_ OK); return;} m_hmap = createfilemapping (m_hfile, null, page_readonly, null, null, _ T (" myjpg "); // 2. map the entire file to m_pbasemapfile = mapviewoffile (m_hmap, file_map_read, 0, 0);} void cserverdlg: onclosefilemap () {// todo: add your control notification handler code herecbutton * pbutton = (cbutton *) getdlgitem (idc_button2); pbutton-> enablewindow (false); If (m_pbasemapfile) {unmapviewoffile (partial );} if (m_hmap) {closehandle (m_hmap) ;}if (m_hfile) {closehandle (m_hfile );}}

// Some client code void cclientview: onopenfilemap () {// todo: add your command handler code herem_hmapfile = openfilemapping (file_map_read, false, _ T ("myjpg ")); if (m_hmapfile = NULL) {MessageBox (_ T ("failed to open file ing! "); Return;} response = mapviewoffile (m_hmapfile, file_map_read, 0); setbitstobmp (byte *) m_pbasemapfile);} void cclientview: onclosefilemap () {// todo: add your command handler code hereif (m_pbasemapfile) {unmapviewoffile (m_pbasemapfile);} If (m_hmapfile) {closehandle (m_hmapfile);} void cclientview :: setbitstobmp (lpbyte lpbase) {bitmapfileheader * pfileheader; // bitmap file-headerbitmapinfo * pin Foheader; // bitmap Info-headerpfileheader = (bitmapfileheader *) lpbase; If (pfileheader-> bftype! = Makeword ('B', 'M') {MessageBox (_ T ("this program only reads BMP files! ");: Unmapviewoffile (lpbase);: closehandle (m_hmapfile); return;} byte * pbits = (byte *) lpbase + pfileheader-> bfoffbits; pinfoheader = (bitmapinfo *) (byte *) lpbase + sizeof (bitmapfileheader); m_nheight = pinfoheader-> bmiheader. biheight; m_nwidth = pinfoheader-> bmiheader. biwidth; cclientdc DC (this); // create an uninitialized bitmap compatible with the specified DC. Select m_hmemdc = createcompatibledc (DC) in the memory compatible DC; hbitmap = :: createcompatiblebitmap (DC, m_nwidth, m_nheight);: SelectObject (m_hmemdc, hbitmap); // 1. normally display setdibitstodevice (m_hmemdc, 0, 0, m_nwidth, m_nheight, 0, m_nheight, pbits, pinfoheader, dib_rgb_colors); // 2. zoom mode/* rect RC; getclientrect (& rc); int nwidth = RC. right-RC. left; int nheight = RC. bottom-RC. top; stretchdibits (m_hmemdc, 0, 0, nwidth, nheight, 0, 0, m_nwidth, m_nheight, pbits, pinfoheader, dib_rgb_colors, srccopy); */invalidaterect (null, true );: deleteobject (hbitmap );}

void CClientView::OnDraw(CDC* pDC){CClientDoc* pDoc = GetDocument();ASSERT_VALID(pDoc);// TODO: add draw code for native data hereBitBlt(pDC->m_hDC,0, 0, m_nWidth, m_nHeight, m_hMemDC,0,0,SRCCOPY);}