Present your images from the couch with Gwenview, MPRIS & KDE Connect

((Okular contributors, take a note of the end))

KDE Applications 18.04 Feature Freeze is setting in. Or: reminder to do finally that feature you always wanted to implement.

This time for me it’s remote control for presentation-like media shows. Think slideshows of images/videolets e.g with the image browser Gwenview, or presentations given with the document viewer Okular. Would be nice to do this from across the room or stage, being deep in your comfortable furniture or when standing by the auditorium, would it not?

There is your wireless input controllers to help you. But…

… we want more, like:

• seeing ourselves the notes for the current slide
• seeing a preview what is coming up
• being able to jump straight to a picture or slide without everyone seeing our desperate search for that in the overview list (avoiding also spoilers with not yet shown ones)

Obvious idea: use your smartphone as rich remote control. Just write a controller app which talks to your app on the computer running the presentation. Profit.

Though only profit for the given app. Would it not be nicer if there were some standard interfaces, so remote controllers would work across applications? We have seen that before, for music and movie players. In the FLOSS world there is e.g. the Media Player Remote Interfacing Specification (MPRIS). And if we think about it, “media” is an abstraction, one which also can cover images & slides. Though the rest of the spec then uses concepts and terms which are rather bound to typical music players, like “track” or “playlist”.
So not usable for our purpose. Or? If we ignore the actual terms, we find we can map their abstract data model with some flexibility onto the data model of a simple one-dimensional slide-by-slide/image-by-image presentation. And by doing so instantly can get access to the existing MPRIS controllers, allowing us to walk through the slides, going fullscreen, start playing & pausing and so on. Controllers like e.g. the MPRIS-based media controller plugin for KDE Connect.

So it’s just adding a MPRIS-wrapper to e.g. Gwenview or Okular, and we have some initial working remote controllers for them. Now this sounds fancy to have, no?

And for Gwenview, I can happily report that by some hard review work of Henrik F. a first version has just been merged. Shipping to everyone as part of KDE Applications 18.04.

For Okular we have a similar patch. Though it needs some good souls to give it a complete review in the next 7 days, otherwise it will miss out for the upcoming release and be at least delayed some more four months.

The patches should be also interesting to adapt for photo management applications like Digikam or KPhotoAlbum.
So want to give your vacation report to your friends while sitting next to them on the couch as well? Have a look at those two patches and try to adapt them for those applications, you will see it is rather simple value and action forwarding code 🙂