i have these code for work with printer:
Code:
void print()
        {
            string windowtitle;
            GetWindowString(hwnd,windowtitle);
            DOCINFO doc = {sizeof(DOCINFO), windowtitle.c_str()};

            unsigned long lPrinterNameLength;
            GetDefaultPrinter( NULL, &lPrinterNameLength );
            char szPrinterName[lPrinterNameLength];
            GetDefaultPrinter( szPrinterName, &lPrinterNameLength );
            //DebugText(szPrinterName);
            HDC pDC =CreateDC( "WINSPOOL",szPrinterName, NULL, NULL);

            StartDoc(pDC, &doc);
            StartPage(pDC);
            HDC windowDC=GetDC(hwnd);
            RECT windowrect;
            GetClientRect(hwnd, &windowrect);

            int w = windowrect.right;
            int h = windowrect.bottom;

            StretchBlt(pDC, 0,0, w, h, windowDC, 0, 0, windowrect.right, windowrect.bottom, SRCCOPY);

            EndPage (pDC);
            EndDoc(pDC);

            DeleteDC(pDC);
            ReleaseDC(hwnd,windowDC);
            DeleteDC(windowDC);
        }
how can i convert the h,w from pixels to twips?
i have seen several codes but without sucess
can anyone explain to me how can i do it?
(the image printed is correct, but very small)