Switching between windows and flashing while preview + render to disk is active

Ok, this might be a bit of a weird one, but I just managed to produce a problem that I've been meaning to reproduce for a while now:

Sometimes, when I and rendering something to disk while the preview is still also rendering, all UF windows start flickering erratically and the program becomes all but uncontrollable. In most cases I can somehow hunt down the window in question and close it or pause the rendering to disk, but in some rare cases it just crashes instead.

How to produce the bug:

1. open a few windows with different fractals, I had 6 fractals open in this case
2. I opened a 7th fractal (parameters below)
3. I started rendering the 7th fractal to disk in 16k resolution and hilarity ensued

The only way to stop the flickering and jumping between UF windows was to either close fractal 7 or let it finish rendering the preview. The window swapping also continues in the background while other programs are usable normally.

Here's the fractal in question:

27 {
::CXMCuin2tLVsOuNMM09Ak/BBvnERJLZrWoheLd5GuhuXozW2W4klMkVav83XalcBXLK6UXKQ
  9EN5jP+o4bIZ6yG/H2vjQyus3qrYNVkv76zTamQSJTW34UWDMKl4NXspVNbDdXy27yr6qnmc
  evb5jqTA9Ejy4V73VAWItzskdxgu6xtUEoiEXMdu8FNgEObTj25YvVH/mNhdtf3sZZxFGv2s
  NktJN9YjUpARj4EAHBJIFMOIIzmxAWkyVSZNVxJmwIuBHAO7Ij3q2vbImmP7NFymNv62YjVD
  MyiN1NZ7eRHHGIDOvNYmxd/zBTyve88wcFBnd6iuacLV2umVPXtRzyXf248bqv8dkiZQSWtZ
  QfA/ttpWUfCjAebtUdtlFA1JnTBVzJEDVyRQY+UMvtAMJtVKLVEKFDbyFWd92iu7tYM+ethj
  kTmw6AuFeXwaSvT6LTou7831dZV+kfMeT1vRDgxdRfM9AC6LR84TeyknIPaDj5JEc8c++s/l
  xtf3Yy07wJUquOHjoN5idlgLipcnPAttEXo3+qG4KSZS6aoGoNib5PACZ56WqJUtQN7tS86b
  pxboqmpEoeu6Xe/EDxb4p3dTMh43a7ew09yYKeO0/TOv/7z+T+s/+Gtcxo1NhvcW82d9F8fb
  z2PAPiIkiD==
}

Gnarls.ufm:gnarltest9b {
; Original formula otto magus
; modified Evan Bayliss May 2021, April 2022
; Three chosen gnarlic formulae are calculated
; One result iterates into the next
; Three chosen post function formulae are concurrently calculated -
; one after each gnarlic formula
; The final post function values are combined using Statistics derived from
; jlb.ucl and the Physicist 12 August 2021 Forum Post
; simplified to play around with by Phillip S.
::TgUwegn2NCVXrRMIQw3F8/wSKFyHHhkDuHuSFC9fiNxcsgRFjHkEuf8dN2c0Xap+i7Oz4MrL
  nhGM8GntBC4FHuo0cGnADAhr8EaDnptWHpZxqHIAvSqz3K4s1UPOJvt37tBqt3On3RlFQFk3
  cCaLgSYGNJQy7xk1veGE7uDwC9sdzrgOX73yjuXEZXJ21fyGTY5gNO4LPjqEWPA3i6tjjzqQ
  Lnp0zqfNq26LU1fHYSz/J2Sg+oUimBckzOWjp7KgmlPlo2ePu1fs949uYLnNoGl31RwAG0KR
  2MO50K4mR61B1cAumxZTyloPiL0erXZil5N1ngm6iI5Nj4Mn5Ue0Og9YYVQ6cSvcCSp0LdB0
  aEZfkmhsnBLabSn6m9Zf/Vc2X8e6VKG=
}

phs.ucl:GnarlAlgo {
::LnRrHin2tW1yutNMQw7Gw/DLsvY5g4mmjBxAxJooXyhgmcsAFbkokJAFpg06WH/1X+SPMjoS
  BaMgfglrmZ5whj5SOdz8ZAkLUIBVItH2CXtxUKVVWJYHhTKRmu4yK+RmovX6Pqn466XvBWbW
  sfFu83v4X8rbgv46sf5S84vaIWVHRuyjUiSRfFhSVZnTfXp4rNrWeCu0OdJmV459IfrtPTVY
  IdtFZyMeu/ZuLVJU13/GsdLsgUEKg09osgp3Gg+bBbhDH3wY+8CAJUedA/dg6FR7XX0xZrKe
  a+scuEF3MG/vY5/JzT+ITWQ79cvkLz0nEbh7yYyGO9mWyN4b5V0w6w5VHO7MzNoyhvJzmAiu
  Dq1r0HgD2XJJxQewEuG+/pJ2+wrH2jZtwq15GCrpkQW69BO7ZyHhUME+4HUzh93jPImVahqt
  T/IFF6H68Z7G4zOfymS7uMqy6JOGzwifgZ8DNa1/fZGMbp1wqPh5JqUsru4QJTSGz0gz7wxp
  HfIg+eHQUOeErLYNE8M3abfWfxME/2siYQIUFrMv7MFJvzIcWLGZJ68MVYzZ+KdmTUQE2YCj
  sJwGXIaIEBpeZsc8gwl6TcSrEaY+uErFwDGg1qzih/jQNWC+7yOg9AYT394a7yl9Za3Pghtf
  lrATeoEGNsLI4a4t2pSeGLnA+pjM/roXjf/twJucECaMX74etxtPx8BhcF7guX9nP7vAMvtR
  7B==
}

Very strange! Can you reproduce the flickering with the steps you mentioned? And I assume you're on Windows?

I'll try again, later today if I find the time, otherwise I'll have to do it next week.

Platform is Windows 10 Professional on a Ryzen 9 3900X, 32 GB of RAM. Opening something and clicking render to disk before it finishes the working window render while multiple things are open is what usually causes it, but in most instances UF has been running for a while (days at a time). We'll see if I can produce it in a reliable way.

I have a very similar Windows system to yours - Win 11 Pro OS, Ryzen 9 3950X CPU, 32GB RAM.

I followed your points for reproducing this - 6 fractals open then the above as a seventh. I don't know how big 16K would be in pixels so I just picked something large-ish (8000x3750) so it would take some time to process and started the render while the preview was still underway.

I did not experience this problem, I'm afraid.

Incidentally, I pasted all of the above into UF but your parameters threw up a message about a missing "colorby" parameter in "GnarlAlgo" which may explain the different colours I saw in the image so I don't know if my findings could have been affected by that?

PS. I always shut down my PC every evening so your comment about leaving UF running for days does have me wondering if that can cause the program to get a bit muddled with this stuff. I occasionally have to restart UF if I've been thrashing it for some time with lots of very quick, heavily detailed changes... it can behave a little oddly sometimes!

Yes I also suspected that long runtimes and lots of work might somehow cause some buildup in a dark corner of the OS or UF memory that eventually leads to problems. That being said, it's odd that the paste is not working, I used Edit -> Copz Formulas and then pasted everything here. Colorby is the parameter that selects how the colors are calculated (via dropdown).

I can send you the CA if you want, but I don't think it will help in tracking down the problem, because it is in no way linked to this particular CA, I have experienced it well before I even wrote it.

Also, I plan to eventually publish it all anyway. It's basically the 24 year old garl formula that exists in several verions with hundreds if not thousands of combinations of variants, but started from scratch so I was able to understand what was happening in the first place.

//edit: 16k is 15360 x 8640 (4x the dimension of 4k in each direction, 16x the pixels)

I have frequently found problems when UF has been open and running for hours, especially when developing formulas, making mistakes, and having to do Ctrl-Z to get my fractal back. Restarting UF always is sufficient.

I usually restart my Windows PC about once a week, even if there are no problems, as Windows is imperfect.

I can send you the CA if you want, but I don't think it will help in tracking down the problem, because it is in no way linked to this particular CA, I have experienced it well before I even wrote it.

That's ok, Phillip, I'm not that bothered by this though it is curious I get a different result because I carefully copied/pasted ALL of your parameter text and formulas above this time.

If it's of any interest I DO get "Gnarl Coloring" with a "ColorBy" parameter displayed in UF - this has ten options listed but it's the default "Total Path Length" that is selected.

//edit: 16k is 15360 x 8640 (4x the dimension of 4k in each direction, 16x the pixels)

I see, thank you.