Show preview of folder content when browsing songs by folder

[achimmihca]

Actual behaviour

The same folder icon is used when browsing by folder.

Expected behaviour

A preview of the folder content is shown in addition to the folder icon, similar to how Windows shows a preview of folder content.

This could include the covers of songs inside the folder.
Further, looking for a dedicated preview.png or preview.jpg as folder icon might be a good addition.

See also original question on Discord

How it was done in related UltraStar games

The following presents how it was done in previous UltraStar games for some inspiration. Keep in mind though that their approach might not be the best solution to the problem.

UltraStar Deluxe
USDX themes come with a set of common language flags, which get shown when folder view + sorting by language is enabled.
Besides that, there exists a txt file where custom image file names can be set for category names, which get shown when sorting by tags and folder view are enabled.

Vocaluxe
There is a folder called "Covers" in the game directory. The game looks for images with matching names as folder icon.

For example, if you sort games by folder name and have a folder name called "Party_Hits" containing your song folders, the game is looking for an image called "Party_Hits.jpg" in the "Covers" folder. If you order by artist and have songs for the artist "Linkin Park", it is looking for an image called "Linkin Part.jpg".