I'm testing some features in Alfresco by uploading document files such as doc,pdf,xls,ppt and viewing the content from the repository management. And I need to know how Alfresco WCM convert and view these files, does anyone know how? Does Alfresco have it's own converter and viewer for files or does it use a third party software? Is there a way to use this converter and viewer from the Alfresco API?
Office documents like doc, xls, and ppt are converted to PDF using OpenOffice. Then, in Share, we use pdf2swf to convert the PDF documents to Flash, and the preview component shows the flash file. You didn't ask, but graphic formats, like png, jpg, and tif are converted using a program called ImageMagick. With Alfresco 4 I believe we are also now supporting multimedia previews, Mac iWork, and the Adobe creative suite.
If you are trying to create thumbnail versions of documents, you can invoke that through the API using the thumbnail service. If you want to simply go from one format to another you can use the Transformation Service. Check the wiki and docs.alfresco.com for details.
The viewer component is embeddedable within your own Alfresco-based apps. I don't know of any good examples off the top of my head, but if you look at the Share source you can find the components that make this happen.
I don't think that Alfresco have it's own direct document viewer for pdf, docx or pptx files, for I haven't find such application. So, when I need to use a doument viewer, I would like to refer to some third party, like <a href="http://www.rasteredge.com/how-to/vb-net-imaging/pdf-windows-viewer-create/">pdf windows viewer</a> for load, view and annotate pdf document on windows side with high speed for pdf viewing.