Retained Themes with Multiple Themes and TOC Navigation

[bluefirepatrick]

There is an issue where Themes are retained on certain chapters after changing the theme and navigating with the TOC.
I have tested this on Safari, Chrome and Firefox for MacOS.

Steps to reproduce:
From playground/sheets

1. Open Moby Dick (reflow)
2. Use the TOC to navigate to a Chapter 6
3. Page forward to Chapter 7.
4. Change the Theme to Paper
5. Page forward to Chapter 8.
6. Change the Theme to Contrast 2.
7. Page forward to Chapter 9.
8. Change the Theme to Contrast 1.
9. Use the TOC to jump to Chapter 5.
10. Page forward through the Chapters.

Some chapters are retaining old themes.

This seems to be tied to adjacent chapter that have been loaded and themed, perhaps due to caching in _cframes. Different browsers seem to have different manifestations of the issue but all have some form of retained themes.

Using the arrow key pagination buttons alone does not cause this issue.

[JayPanoz]

Ah yeah thanks for logging this issue as it will help keep track of the resolution. 🙏

That's a long-standing issue that I hope should be fixed once and for all after implementing the Preference API in TS-Roolkit. It impacts colCount as well but not scrollable/paged since we can update the navigator manually for the latter.

Ideally the Preference API should take care of everything w/o having to trigger anything on the Navigator instance.

[HadrienGardeur]

This should be resolved by readium/playground#64

[JayPanoz]

I can confirm it should be resolved since the Preferences API is messaging hidden frames in addition to the current one to set the properties and have everything in sync immediately. It’s kind of using an aggressive strategy to make sure these styles are committed and applied across the frame pool.

That said, if that’s not the case, please feel free to report it as I’m aware there may be quirks that are harder to anticipate here and there.