Q: I had a few questions related to Native to XOD conversion.
1) I've read that an XOD is just an XPS file that has been optimized for online viewing. So, is XOD a format specific to PDFTron? Is there any official documentation on what makes an XOD different from an XPS?
> what makes an XOD different from an XPS?
These days you can create XPS files from any Windows program (via Print to XPS). In some ways XOD is just a subset of XPS. You can rename XOD to XPS and view it locally on any Windows machine (or use .NET framework for viewing or manipulating it in your app - http://msdn.microsoft.com/en-us/library/ms748388(v=vs.110).aspx
To guarantee fast viewing across mobile devices XOD does not allow some XPS features (e.g. TIFF, HDPhoto, file interleaving, etc). At the same time XOD organizes file in a way that it can be efficiently viewed without need to download the entire file (this is similar to PDF linearization http://blog.pdftron.com/2013/08/24/streaming-a-pdf-from-the-web/
XOD also includes optional Unicode representation of all text in the document (which could be used for client and server side document indexing, search, and in the near future reflow ...).
> 2) For PDF conversion, I've read that for Office 2007 SP2 or higher documents, PDFNet
> will try to use Office interop, and if office is not installed, it will fall back to the virtual printer. Is this the same for XOD as well?
Yes, everything that applies to PDF also applies to XOD. PDFNet can directly normalize PDF and XPS to XOD. So anything that can convert to PDF/XPS can be used to power your WebViewer solution.
PDFNet supports a few direct PDF/XPS/XOD converters (e.g. HTML to PDF, EMF, image, etc). To add viewing support for another document format that is not directly supported (say DWG) you would need to find a program that can convert the file to PDF or XPS (a quick search on the web shows many affordable utilities) or can silently 'print' the file (e.g. most 'DWG' viewers can do that). In the latter case you would associate the file extension (i.e. DWF) with the print utility and PDFNet would capture the print output as PDF/XPS/XOD.
In case of MS Office, PDFNet will use COM interop (if MS Office is available) to produce high-quality PDF/XPS/XOD output. For Office files, the currently recommended approach is MS Office Interop (compared to Virtual Print Driver route). For more info please see: http://goo.gl/3b4iw4
> 3) Am I correct in assuming that for some formats (for example, Lotus Notes E-mail files) I need
> to have the native application installed on the machine with PDFNet in order for it to properly convert?
WebViewer (and PDFNet) support a few direct conversions, however it is technically not feasible to support every conceivable format (and other solutions that attempted to support hundreds or built-in conversion always failed). Instead you can extends the range or supported formats in your own solution by integrating with the apps/tools/cli utilities/sdk-s that can export to PDF/XPS or that can silently print the file. So if you want to support Lotus Notes E-mail files, you would need to find a tool that can either convert these to PDF/XPS or that can print.