When a user views a document in the viewer, the document is converted on-the-fly. The type of files created depends on the document view and whether the document was viewed previously.
- Near Native view
- If the native file is an image file, the image is displayed in the viewer.
- If the native file is not an image file, it is converted to a PDF and its text is extracted and indexed to allow users to search within the PDF. The PDF and text file are stored in a temporary cache. By default, the cache entry is removed after 10 minutes if no user has the corresponding document open in Near Native view. If the corresponding document is viewed in Near Native view during that time, the cache entry timeout for that document is extended automatically.
- If a user applies an annotation in Near Native view, the annotation file is stored in the annotation storage and the PDF and text file are permanently stored in the document view storage. This guarantees the integrity between the annotation file and the corresponding PDF.
- Image and Redaction View
- If an XDL file exists, the system starts a conversion based on the already existing XDL to create display files.
- If an XDL file does not exist, the system starts a conversion based on the native file to generate the XDL, which is then used to create display files. On-the-fly conversion takes longer because the XDL file needs to be generated for these views.
- The XDL file is stored in the conversion storage and the display files are cached in the display list cache. As soon as the display files are available in the display list cache, they are displayed in the viewer.
The cache is size-limited, and files that have not been used for the longest time are automatically removed from the cache.
Note: Display files are SVG files plus JPG files for thumbnails that are sent to the browser for display, plus a text index, which is required for searching within the view.