preview: support previewing EPS files

[tiborsimko]

Physics workflows' output plots are often produced in the EPS (=Encapsulated PostScript) format.

These files cannot be currently previewed when browsing the Workspace tab files.

Let's investigate whether we could add support for previewing EPS files too.

[tiborsimko]

(Note: as an alternative option to finding a nice frontend-side image viewer solution, one could think of creating flexible backend-side image manipulation first before the source file is passed to the previewer.. E.g. using the ImageMagick helper tool would convert EPS files to PNG on the backend side and the frontend would visualise PNG. Such as approach is more complex, but might have an advantage of being possibly used in the future for other specialised file formats.)

[giuseppe-steduto]

1️⃣ Converting the EPS files on the server side is very likely the best idea. For this there are plenty of options available (ImageMagick, Ghostscript, cairo2svg, ...) and this option has indeed the advantage Tibor mentioned.
2️⃣ There don't appear to be many EPS rendering client-side libraries (or even more general PostScript visualization tools). Rather than well-maintained libraries, most of them seem to be didactic projects or exercises (such as this or this).
3️⃣ Instead of a client-side EPS file renderer, one could think about using a client-side converter from EPS to, say, SVG. The situation is not much better though: I managed to find only one, old library (nevermind, it was yet another server-side library)

(Note: I'm deliberately ignoring external APIs like CloudConvert, Cloudmersive and such)

[audrium]

I fully agree with Giuseppe. I haven't found any client-side libraries for previewing EPS files, so we should take the server-side approach.