Channel limitation for browsing

[NKalavros]

Hi!

Amazing visualizer, saved me hours upon hours of work. I'm extremely thankful!

I've been using it to deploy visualizations on mostly H&E so far and tried to create one for MxIF (PhenoCycler Fusion).

So after the image is created just fine, I've been encountering a specific WebGL error precisely at 65 channels.

Error: Fragment shader texture image units count exceeds MAX_TEXTURE_IMAGE_UNITS(16)

It seems to be related to the fact that the channels are split every 4 into different files, making for 17 files if you have >64 channels. I changed the nc if line in image.py to 5 and it seems to work so long as the image is 16 files or less.

Another, less important issue is that to show the rest of the channels I have to zoom out of the web page (Ctrl + -) because otherwise the channel menu takes too much space.

EDIT: If you try to make files with larger than 10 channels, the gdal_translate call will fail because of the JPEG library's limitation to 10 channels. The call can be changed to use LZW or deflate with BIGTIFF=yes.

[chaichontat]

Ah, thank you for the insight and troubleshooting! I think the I used 4 channels because of limitations in JPEG compression but will look into that.

I can add a scrollbar to the channel selector to deal with this case.