C / C++ / MFC

// create a device context compatible with the screen<br />
CDC memDC;<br />
memDC.CreateCompatibleDC(pDC);<br />
<br />
// create a bitmat compatible with the screen<br />
CBitmap memBitmap;<br />
memBitmap.CreateCompatibleBitmap(pDC, nWidth, nHeight);<br />
<br />
// select the bitmap into the device context<br />
memDC.SelectObject(&memBitmap);<br />
<br />
// draw into the memory area ie draw as normal but use memDC instead of pDC<br />
<br />
// copy the image onto the screen<br />
pDC->BitBlt(<br />
nLeft,<br />
nTop,<br />
nRight,<br />
nBottom,<br />
&memDC,<br />
0,<br />
0,<br />
SRCCOPY);

long lColor = *(long*)(&rgb);

RGB rgbGreen = RGB(0, 255, 0);<br />
// since RGB is defined as a DWORD, a cast is required<br />
long lColor = (long) rgbGreen;

1. Read the Jpeg to a RGB buffer.
   
2. Swap RGB -> BGR.
   
3. DWORD align.
   
4. Vertically flip.
   
5. CreateDIBSection.
   
6. memcpy the flipped buffer to the DIB section.
   
7. ::StretchBlt().
   

void CMyView::OnPdfPrint() 
{
	DOCINFO			di;
	CPrintInfo		printInfo;
	CString			filename;
	CDC				dc;
	CRect			draw_area;
	char			fname[_MAX_FNAME];
	
	memset(&di, 0, sizeof(DOCINFO));
	
	CFileDialog		dlg(FALSE, "PDF", filename, OFN_OVERWRITEPROMPT | OFN_HIDEREADONLY, "Adobe acrobat PDF files (*.pdf)|*.pdf||");
	
	if (dlg.DoModal() == IDCANCEL)
	{
		return;
	}

	AfxGetMainWnd()->EnableWindow(false);    // disable main window
	CPrintStatus dlgPrintStatus(this);
	dlgPrintStatus.SetDlgItemText(AFX_IDC_PRINT_DOCNAME, "Creating PDF interface");
	dlgPrintStatus.SetDlgItemText(AFX_IDC_PRINT_PRINTERNAME, "");
	dlgPrintStatus.SetDlgItemText(AFX_IDC_PRINT_PORTNAME, "");
	dlgPrintStatus.ShowWindow(SW_SHOW);
	dlgPrintStatus.UpdateWindow();
	dlgPrintStatus.PumpMessages();

	try
	{
		// start the PDF ole interface
		ICDIntf	pdfInterface;
		// Start Excel and get Application object.
		if (pdfInterface.CreateDispatch("CDIntf.CDIntf"))
		{
			// success
			long lPdfError = pdfInterface.PDFDriverInit("Sirius PDF Generator");
			
			if(lPdfError != 0)
			{
				//An error should only occur when lPdfError == 0 but hey what the hell.
				return;
			}
			
			pdfInterface.SetPaperSize(9); // Sets to A4
			
			pdfInterface.SetDefaultFileName(filename);
			pdfInterface.SetFileNameOptions(1 + 2 + 32); //NoPrompt + UseFileName + BroadcastMessages

			HDC hDC = (HDC)pdfInterface.CreateDC();
			if (hDC != NULL)
			{
				OnAboutToPrint();
				di.cbSize = sizeof(DOCINFO);
				di.lpszDocName = pDoc->GetPathName();
				di.lpszOutput = filename;
				
				// prepare the print information structure
				dc.Attach(hDC);
				printInfo.m_bDirect = TRUE;
				printInfo.m_rectDraw.left = 0;
				printInfo.m_rectDraw.right = dc.GetDeviceCaps(HORZRES);
				printInfo.m_rectDraw.top = 0;
				printInfo.m_rectDraw.bottom = dc.GetDeviceCaps(VERTRES);
				draw_area = printInfo.m_rectDraw;
				
				CString strTemp;
				dlgPrintStatus.SetDlgItemText(AFX_IDC_PRINT_DOCNAME, fname);
				dlgPrintStatus.SetDlgItemText(AFX_IDC_PRINT_PRINTERNAME, "PDF Generator");
				dlgPrintStatus.SetDlgItemText(AFX_IDC_PRINT_PORTNAME, "");
				dlgPrintStatus.UpdateWindow();
				
				dc.StartDoc(&di);
				OnPreparePrinting(&printInfo);
				printInfo.m_rectDraw = draw_area;
				
				// start printing the document
				for (printInfo.m_nCurPage = 1; printInfo.m_nCurPage <= printInfo.GetMaxPage(); printInfo.m_nCurPage++)
				{
					strTemp.Format("Page %1d of %1d", printInfo.m_nCurPage, printInfo.GetMaxPage());
					dlgPrintStatus.SetDlgItemText(AFX_IDC_PRINT_PAGENUM, strTemp);
					dlgPrintStatus.PumpMessages();
					dc.StartPage();
					OnPrint(&dc, &printInfo);
					dc.EndPage();
					// reset page size as OnPrint may have odified them when
					// header / footers were added to the page
					printInfo.m_rectDraw = draw_area;
				}
				OnEndPrinting(&dc, &printInfo);
				dc.EndDoc();
				VERIFY(dc.DeleteDC());
			}
			else
			{
				// failed to create the HDC
				AfxMessageBox("PDF Driver failed, unable to create DC");
			}

			// Remove the driver
			pdfInterface.SetFileNameOptions(0);
			pdfInterface.DriverEnd();
			
			pdfInterface.DetachDispatch();
			
			// pop-up the pdf viewer
			if (atoi(RegistryProfile::GetProfileStringLM("PrintSettings", "StartPDF", "1")) != 0)
			{
				ShellExecute(NULL, NULL, filename, NULL, NULL, SW_SHOWMAXIMIZED);
			}
		}
	}
	//Catch control-specific exceptions.
	catch (COleDispatchException * e) 
	{
		CString cStr("");
		if (!e->m_strSource.IsEmpty())
		{
			cStr = e->m_strSource + " - ";
		}
		if (!e->m_strDescription.IsEmpty())
		{
			cStr += e->m_strDescription;
		}
		else
		{
			cStr += "unknown error";
		}
		AfxMessageBox(cStr, MB_OK, (e->m_strHelpFile.IsEmpty())? 0:e->m_dwHelpContext);
		e->Delete();
	}
	//Catch all MFC exceptions, including COleExceptions.
	// OS exceptions will not be caught.
	catch (CException *e) 
	{
		TRACE("%s(%d): OLE Execption caught: SCODE = %x", __FILE__, __LINE__, COleException::Process(e));
		e->Delete();
	}
	dlgPrintStatus.DestroyWindow();
	AfxGetMainWnd()->EnableWindow();    // enable main window
}