Currently OpenOlat can generate thumbnails for PDF, movies and images. The goal of this issue is to also have thumbnails for various document types such as word, excel, powerpoint, html, txt, epub etc.
The implementation is based on the OnlyOffice conversion API, thus an OpenOffice installation must be installed to have this support.
- Implement admin UI to enable / disable the conversion (part of OnlyOffice configuration) Enabled by default when OnlyOffice is available.
- Implement a DocumentToThumbnail class that implements ThumbnailSPI
- Implement upgrader that resets the not-generated thumbnail info for the supported filetype so that at next viewing the thumbnails will be generated