Hips placement issue

[emellega]

We have noticed that the hips tiles are not placed correctly for some users. When you load the hips you can see it flickering as the tiles are placed on top of each other as they load. The end result is that only one hips tile is shown.

I created a JSBin to illustrate the issue, and to see which version it stopped working in. It works correctly with 3.5.1-beta in the url, but not with v3.6.0-beta (nor with 3.6.5 or "latest').

It seems to happen with all hips and no matter which projection you're using.

The only computer we have seen this issue on is running:

MacOS Catalina v10.15.7
Firefox: 138.0.1 (64-bit)

Here's a screenshot:

[tboch]

Hi @emellega : does this happen whatever the zoom level, or only for wide field of views?

[emellega]

It happened on any zoom level. Or many of them at least, I don't remember if we tried zooming in a lot. But it was not only for norder=0 at least. And we could see the tiles loading in the network tab, they just didn't display properly.

[tboch]

Could you send a short video illustrating the issue? Otherwise, it would be difficult to understand a bug we cannot reproduce.

[emellega]

My team member whose computer we noticed this issue on is on vacation this week. I used a free trial at BrowserStack to record a video from a Mac running Catalina and Firefox 138 (although I think I used version 135 in video here, you can only browse for one minute in each version). I captured the video in 50 fps, but I still didn't manage to capture the "flickering" on video. The flickering is pretty fast, although 50 fps should have been more than enough to capture a few frames of it at least. I don't think it really managed to capture at 50 fps...

Here's the video:

video2.mp4

I toggle between Fermi and DSS2. In the middle of the video I tried zooming in. I can see the tiles flickering then as well, before everything going dark. Probably because all tiles end up in the same place somewhere out of view. None of the flickering can be seen in the video unfortunately.

If you want to see it for yourself you can try BrowserStack yourself maybe, this url should load aladinlite for you on a Mac running Catalina and firefox 138.

[emellega]

She was actually going on vacation later this week 🙈. She recorded this video where you can see the issue much clearer:

aladinLite4CDS.mp4

[tboch]

Thanks @emellega , that's very useful.