Allow more than 6 channels to be selected at once

[rlreamy]

When working with our experts, many of them want to be able to view up to 8 channels at one time, though most agree that more than 8 is not terribly useful.

Currently Vitessce allows only 6 channels to be displayed at once, though there are 8 colors to choose from. Can the max channels either a) be increased or b) be configurable by the user?

[ilan-gold]

The limit is set by our imaging library. We have tended to shy away from bumping the number because we found no more than 6 useful. I'll raise this. It would help if you could share a screenshot to demonstrate the usefulness of this. You could try opening the image in Napari or QuPath. I'm not opposed but just want a solid use case before making a change to an lower level library.

[rlreamy]

We are working with CODEX data that have 44 channels. Here is an example where they selected 8 channels at once.

And another where they have zoomed into different portions of the slide with 8 channels on:

[rj3d]

Reviving this old topic.

@ilan-gold, is this still a limitation with the rendering library?

We are working with MIBI data, which can have 40-50 channels. We have found that more than 6 colors aren't really useful, but it has been useful for us to be able to load more than 6 channels and then map multiple channels to the same color.

[ilan-gold]

@rj3d That is an interesting use-case....this is not on our radar at the moment. The only thing I can think of at the moment for you would be to customize the loading to combine the channels on the CPU, but that might be too slow. Unless you had a specific number in mind, rather than just ">6 is better" I'm not sure we are going to budge on this....I'll ask internally though. Maybe it is time.

[ilan-gold]

For example, in the above, I can't really see any MPO because there is so much purple (it probably mixes with the blue so it's hard to tell).

[ilan-gold]

I would say if you're interested in seeing this done to make a PR for it and we can discuss internally.