[_bittere]

Yeah, sure! So there's a few ways you can think about it.

In a more general case where you can make no assumptions about what you're rendering, you first render whatever is on-screen (so that you can also calculate their heights and position other elements properly). Then you render everything else off-screen, measure the total height and set that as the height for your container (for your virtual list).

Then you could implement some sort of caching for the heights to reduce recalculation for future loads.

If you can make some assumptions, there are a lot of clever ways you could even skip the rendering-then-checking-height method completely. One example I can think of is for is images; the height of an image is already present in the metadata. You just have to multiply it with some scaling factor to make it fit in your UI. That's much faster compared to checking the height after rendering.

What Seen currently does is the first. But the next version is going to do the second: finding a way to set a note's aspect ratio constant across all configurations of screen sizes, so that you no longer have to wait for all that calculation to finish.