Accent the main post in a CollectionView

[CodedOre]

Since all posts are displayed quite similar in the current style, it might make sense to accent the "main post" so it is clearly recognizable in a Thread view.

This branch colors the background of the main post in the accent color:

While this works in focusing the main post, it might be worth discussing other designs for focusing the post before settling on this, hence this PR.

[IBBoard]

Agreed that the main post needs some focus. Not convinced by the blue. It makes it look like it's selected! Putting the current post on a darker background would be the wrong way around - it would de-emphasise it. Would it work to put the others on a slightly darker background, or does that not work in libadwaita's approach? (I've seen another widget discussion that was "we can't do that because that's not how libadwaita groups things and lays them out)

Cawbird obviously does it by having it in slightly bigger font. I guess it depends how much you want "current post" and "other posts" to be identical rendering.

It seems a bit odd that there's not a line down from the main post… but then again, that might only link it to the first sub-thread. Could you indent the sub-items like a tree and highlight two things in one? (current post is the last of the not-indented, and clarity of where sub-threads start)

Oldest post
|
Old post
|
Current post
|
├─ Reply one
|    |
|    Reply one reply
|
└─ Reply Two

[CodedOre]

Would it work to put the others on a slightly darker background, or does that not work in libadwaita's approach?

From a technical standpoint, we can color the background of the list and the rows individually:

The main issue here is: "What colors would work?" and that we probably would need to define our own, rather than using the named colors from libadwaita, which may or may not be an issue...

(I've seen another widget discussion that was "we can't do that because that's not how libadwaita groups things and lays them out)

That was probably about mixing separators and border-radius, or styling the first and last row differently, which is limited, but of concern here.

It seems a bit odd that there's not a line down from the main post… but then again, that might only link it to the first sub-thread. Could you indent the sub-items like a tree and highlight two things in one?

Then we need to rework PostItem and how Threads are stored... As of now the lines are simply defined by if the latter post replies to the former, with the exception of an "main post", where the connection to the latter is not displayed, because multiple replies for the main post can be displayed.