Offset between layers

Hello,

I've seen this several times now with different fractals, and I don't know what causes it, but sometimes multi-layer fractals are offset. This problem seems to go away when activating anti-aliasing in the working window. Here's a screenshot:

It seems to be always exactly 1 pixel along the y-axis of the monitor, no matter the rotation of the fractal. And it also remains 1 pixel while using shift + mous drag to zoom, here's an screenshot while doing that, you can see the offset at the border between the enlarged pixels:

Here's the fractal:

Copy2Of11 {
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}

Gnarls.ufm:gnarltest6b {
; 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.
::UQ3Chgn2l9UzqRIMQ47Bm3hB7Fd3FR3y2DlGYp36p+GsQqGlBiJBNLoy+w3Jm26hmLJf/NfT
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  7Q2fFLrrSnSOi22ul63w8E/g76zuuJdAEI+TI+ftX/eovJwnzRI=
}

phs.ucl:GnarlAlgo {
::oNnHfgn2tSVTrJMQQ07C+fYIexkiWbPKNgWp0LeQqesQZ1sJuwmdDJbaV/139rYCpZjFa9ih
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  /fjGUXpAY8/gecaFLzTKTxMhaYqR/utcqxHaRf9EgTOWjyTwFCYLRP2uVuY2G/q16G7zR4YU
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  59to21aF8uhM7PnT9/cotnZp2g6qJ7u1U7VDH89fgI92
}

I'm afraid I can't load these fractals as I don't have the "gnarltest6b" formula (if you've included that in the above text then forgive me, I don't know how to use that information, sorry).

Is your offset only apparent with this one formula or is it universal to all? Does it render with those unwanted lines or could it be a display artefact of some kind, perhaps? Sometimes what you see is not always what you get with UF.

...just tossing around a couple of ideas, really. I have no real idea what might be causing this.

Hello,

that was the output from "copy Formulas" so everything should be there, I wonder why you can't load it. To your question:

• The offset is not universal, but it's also not limited to this formula, I've noticed it before
• The offset does not appear in the final render, nor does it appear when I turn on anti-aliasing on the working window
• Looking at your questions, I re-opened the fractal and noticed that the lines only appear when displaying it in WQHD-resolution. My monitor is 2560x1440 and sometimes I go full-screen for exploring. In fact, it seems to be related to the vertical height of the fractal. I tried a few values and the lines appear only if the working fractal is exactly 1440 pixels high.

Here's another paste:

23 {
::takcgin2lLZzOONMUU49VqvDWZFsYS9fxJFkXMjEChESwbQlnkbSsGH7gjL0+2zNp/QWgQDL
  RkV23cPn7x2ftRTdy4e32NESymcgOjLyI/w2k618CFl0D2u+kmJlUizcGiTa+c31Roxmm0Zf
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  ED+EE1PIyLE8ChQWxl7egpyFUlsUJZlFkBTnXLyV0KaZVFx47wzwe62Nth4wRnZxoBzJ7sT8
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  JLquVXgRkKvxkCB7XMpoUoEl7/rYyfS4vQ70
}

Gnarls.ufm:gnarltest6b {
; 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.
::Av6LGgn2l9UwqRIMUw7By/wD7Fd3FRL0eo0ASv1T9PolU9p8gYSQzCRZ/47L626hmLJz8m5N
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  qsZa0bQYwqnMBcOAPnJFj6YaPqn4/WLaTPzrKvAVlFphDW1jShHnIXH1ShFFrzrn0jweKtaf
  gcWV2b7dI7vgV1V7nS2Ca72c9rZejvzZ9Rf/MGkCAubi/XHxfY6HzoydoD==
}

phs.ucl:GnarlAlgo {
::oNnHfgn2tSVTrJMQQ07C+fYIexkiWbPKNgWp0LeQqesQZ1sJuwmdDJbaV/139rYCpZjFa9ih
  Zm99e7bmZJMiY+wBAET5IBkhEHhQY2UVoD80MK+EchTjkBHlROhp11K+ivhIj/4UIQlsODh9
  5ObyHmC3bqsOdK60HFCc2ViMhbEiy5ZaVZjdAtvY8oLwEtW8VZIx148kuOVUoJ4VBxsISs6D
  7tT/3dXTXd9uMcQMhhoztwv4Anyzf+MEGCe74CEF2oO5aMLRc0zQ3ICLSaRhwiIMrgIOL9CF
  +aepF4r4s3gzSWCFD8Y4FWUPQc1BDGLdWpYRCE7RpF477C5GKMA+7046eY9DdHRasyWShAlL
  8bzSdLzM34fLkchwtPokD93dLEVmKoqq0KJnQv6Iilgl2jxI7UZ95dTc6sWidxM49GKiUWId
  /fjGUXpAY8/gecaFLzTKTxMhaYqR/utcqxHaRf9EgTOWjyTwFCYLRP2uVuY2G/q16G7zR4YU
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  59to21aF8uhM7PnT9/cotnZp2g6qJ7u1U7VDH89fgI92
}

I got the fractal loaded this time, thanks.

I still think this is most likely some sort of display/resolution artefact, especially since you say renders are ok.

I have a 3840 x 2160px display now and have had some mixed results with your fractal:

• The image at 1440px high doesn't quite fill my maximised UF window but it looks ok.
• I changed my screen resolution to 2560 x 1440 and the maximised image, still at at 1440px high, does display this offset, thus confirming your findings on your screen size.
• Going back to my usual resolution and enlarging the fractal dimensions to 3840 x 2122 (thus filling the native width of my screen) - all ok
• Enlarging dimensions to 3840 x 2160 (full width and height of my screen but a slightly different image ratio) - not ok.

It is my understanding that the image in the working fractal window is more of a preview and not a totally accurate representation of the fractal. This is partly so that updates to the design can be applied quickly as you work. I have seen various oddities in fractal windows over the years so something like this in a working window does not surprise me. Granted, these unwanted lines are a bit perplexing but if the final renders are coming out as intended then it is probably just be a quirk of the visual environment you have to live with.

Of course, I could be totally wrong. In which case I'm sure someone will be along in a while to offer another explanation!

Yes, don't get me wrong, it's not a big deal. It's just something I've noticed happening sometimes over the last years and finally decided to report. As to its priority, it's not too bad, but some fractals, especially detailed ones, look a lot different when it happens.

I've tested the second fractal and didn't get the offset, even at 2560x1440 resolution. Is is random or 100% reproducible for you? Are you using version 6.05?

Out of curiosity I've run a few more tests here with the second fractal entitled "23" with UF 6.05 re-started for every test.

At Phillip's screen resolution of 2560x1440 the overlap effect is totally reproducible here. Changing the image scale in Windows (100% and 150%) made no difference. The overlap (thin white lines) is small but visible:

But there is something curious going on here. Whatever the screen resolution, if I change the image dimensions to match that of the screen resolution I consistently see this overlap. If the image size and the screen resolution are not identical then the effect disappears:

Image size 3840x2160 on screen res 3840x2160 --> overlap
Image size 3840x2160 on screen res 2560x1440 --> OK

Image size 2560x1600 on screen res 2560x1600 --> overlap
Image size 2560x1600 on screen res 1900x1200 --> OK

Image size 1920x1080 on screen res 1920x1080 --> overlap
Image size 1920x1080 on screen res 2560x1440 --> OK
Image size 1920x1080 on screen res 3840x2160 --> OK

Whether this is true for other users I don't know but it is perhaps something to take into consideration.

Curious.
My screen is 1920x1080.
In UF with image size 1920x1080 I get white lines without anti-aliasing:

and no white lines with anti-aliasing:

In UF with image size 1904 by 1071, still the exact 16:9 aspect ratio,
no white lines even without anti-aliasing:

Rendered at 1920x1080, no white lines, with or without anti-aliasing.

UF 6.05, Windows 11 22H2

Very interesting, I can reproduce it now. It seems to have to do with OpenGL acceleration. If I turn acceleration off in View > Preferences > Fractal (needs a restart of UF), the problem is gone. I'll look into it but it seems to be a visual thing in the fractal window only when the fractal size matches the screen size.

I'll look into it but it seems to be a visual thing in the fractal window only when the fractal size matches the screen size.

Yes, it's definitely just a visual bug, it has no impact on renders whatsoever. Testing to turn off OpenGL didn't occur to me, this is useful info, since it is a bit irritating sometimes.