3873: feat configure number of thumbnails

[fstoe]

Hi,
i created a PR which solves issue 3873

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 94.52%. Comparing base (05194d8) to head (f4a13ec).

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #3915   +/-   ##
=======================================
  Coverage   94.52%   94.52%           
=======================================
  Files         313      313           
  Lines       14767    14781   +14     
  Branches     2496     2501    +5     
=======================================
+ Hits        13958    13972   +14     
  Misses        804      804           
  Partials        5        5           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[lutzhelm]

The changes look like they work as intended, but I have a strange feeling about the usability. Maybe it would be better to center the thumbnail navigation if there is a limit applied. If there were only five canvases in the manifest, the thumbnails would also align left (or right for RTL). But aligning a component with a scrollbar to the left feels strange.

I guess I'll try to get some feedback in this weeks community call.

[lutzhelm]

1. Couldn't these two settings be reduced to a single setting? Something like, the count setting does only apply if it is >0. I think we should avoid cluttering the settings with too many options. In that case, the setting should be set to 0 as default.
2. Is there a more precise name than count (or limit, for that matter)? Like maxNumberOfThumbnails, or something preferably shorter?
3. Alphabetical order would be nice to make eslint happy.

[fstoe]

Thanks. I made the requested changes. Let me know if i should center the navigation or not :)

[barmintor]

@lutzhelm is there a way we might have it fetch enough thumbnails to fill the window, and then push/pop canvases with a loaded thumbnail on scroll?