Set tile size manually

[alexeykurbako]

Just a quick question to everyone. Is it possible to set up tile size manually(this ability exists in the original deck.gl but I didn't find any references to in your documentation) for PictureInPictureViewer?

[ilan-gold]

I think this information is part of the underlying PixelSource loader. Why do you need to do that, especially for PictureInPictureViewer? Also I will convert this to a discussion for the time being.

[alexeykurbako]

Hey @ilan-gold Thank you for response. I provide to viewer direct link to my gcp bucket where ome.tiff slides are located and sometimes it tooks to much time to fetch tiles(especially when I do a lot of actions like drag viewer and zoom it) and my Idea was to play a bit with tile size and measure how it will affect tiles loading time. I'm not sure if it helps just wanted to try

[ilan-gold]

@alexeykurbako Your tiles have a fixed size determined when you produce the image pyramid. So changing it in the viewer won't help you. I would recommend regenerating your image pyramid with a different (smaller) tile size. You'll also need to regenerate your offsets.json file.

[alexeykurbako]

Thank you so much. I'll try to do it. One more question from my side: Is it possible to abort requests that fetch non-visible tiles?

[ilan-gold]

This happens with a reportedly variable success rate automatically. I think the mechanism isn't perfect but does exist.

[ilan-gold]

i.e., it's already in our code base. I would highly recommend using OME-NGFF if you can. If you're using the bioformats2raw pipeline, it should be no issue.

[alexeykurbako]

Thank you one more time. I'll try to follow your advices and hope it will help

[alexeykurbako]

Hey @ilan-gold Finally I have to ask for your help one more time. I've got access to original slides in qptiff format and found out how to change tile size but faced with one issue.
I convert original .qptiff file into .ome.tiff in 2 steps using raw2ometiff and bioformats2raw libraries.
Step 1: Run bioformats2raw with --tile_height={tilesize} --tile_width={tilesize} props
Step 2: Run raw2ometiff with input from previous step
Step 3: Generate offsets using tifffile python library(seems they aren't used on a frontend at the moment)
Everything works fine in AVIVIATOR with local .ome.tiff files so decreasing tile size to 256 or 512(at the moment we use default 1024 tile size) leads to significant performance changes(tiles are loading faster than original) but when i try to upload them into gcp performance become even worse then with original tile size. In some cases it obvious because 256 tile size leads to 16 times more requests count and internet isn't perfect but I was really upset when I found out that changing tile size to 896 or 1000 or 1152 also kill tiles loading (up to 2 times).In other words changing tile size makes performance even worse(even changing to 1000) when file hosted on remote storage(gcp in my case) but locally it obveously leads to increasing of tiles loading speed
Tile sizes that I tried: 128, 256, 512, 768, 896, 1000, 1024(original), 1152, 2048)
Tried to do the same tests with 2 different .qptiff files (2 gb and 5 gb) and there is no difference in speed
Maybe I'm missing something super obvious (maybe offset I don't know) that leads to decreasing performance when tile size is not equal to 1024?

[alexeykurbako]

offset.json and slide.ome.tiff are stored in the same gcp folder

[ilan-gold]

seems they aren't used on a frontend at the moment

Are you saying the offsets.json is not used by the front end? This file makes things performant so I would highly recommend making sure it is used.

As for the tile size changes, I can't say I've experimented with it but I have always understood that powers of two are always nicer for your computer's memory layout and efficiency. I can't say specifically why that is the case here, but I'd be curious why you need to try so many non-power-of-2 tile sizes?

[alexeykurbako]

Thanks for response. i didn't know about powered of 2 tile size that's why I experimented with different values. I hardcoded offsets array into loadOmeTiff function that we use and nothing changed(tried 512 and 1024 tile size). I mean there are no visible performance changes with or without offsets(but wrong offsets array without one value cause console error) and seems I stuck

[alexeykurbako]

I looked through docs one more time and found pyramid resolution and pyramid scale props May changing pyramid resolution and scale affect loading speed somehow?