just like Roon Remote is doing.
That sort of thing is probably possible with the various http controllers available for fb2k desktop. Editing the html that is served isn't really going to have any limitations. I know less than nothing about android apps but I'm sure it's an entirely different and more complex beast.
In the case of automatically retrieving and displaying appropriate artist images from the web in accordance with the playback, it may indeed require complex processing that can only be achieved with the desktop version, as you suggested.
But what I am assuming here is a way to display a local Artist.jpg or an artist image embedded in a track.
It is relatively easy to collect artist images from LastFM Artist using the "Albumart Art Downloader" component of the desktop version of foobar2000, and you can embed the images into tracks using the context menu "Tagging > Attach pictures > Artist", right?
All that I need now is the ability to display these locally accessible specific images in the mobile version of foobar2000.
Desirably, the ability to apply standard visual effects such as blurring and brightness adjustment to the [albumart] and [image] elements would be helpful.
The following is an example intended for iPad mini 6.
//Background
[rectangle]
0,0,0
0,0,2250,1500
*if playing
//Artist Image as Background
[albumart]
0,0,2250,1500
artist,blur75
//blurXX means that the degree of the blur effect is 75% (0 < XX < 100). If there is no artist image availbale locally, display nothing.
//Album Artwork
[albumart]
625,100,1000,1000
front
*end
I am not at all familiar with Android app development, but I wonder if it is that difficult to implement these features...
Of course, even if it wasn't difficult, I myself might be asking too much for a free application.
Anyway, I am grateful to the developers of the foobar2000 suite of applications.