+- Gimp-Forum.net (https://www.gimp-forum.net)
+-- Forum: GIMP (https://www.gimp-forum.net/Forum-GIMP)
+--- Forum: General questions (https://www.gimp-forum.net/Forum-General-questions)
+--- Thread: Getting weird pixel artifacts when using animated brushes (/Thread-Getting-weird-pixel-artifacts-when-using-animated-brushes)
Getting weird pixel artifacts when using animated brushes - Jan Thümmler - 09-18-2021
Hi there, newbe here.
I have been using GIMP for a couple of weeks now an am very pleased with my experience so far. I especially like the animated brush feature. Unfortunately I am getting some issues with it. Some custom animated brushes I set up for random scatter get very annoying artifact around the edges. I suspect they might have something to do with the alpha channel?
I am using GIMP 2.10.28 on a Win10 64bit PC and imported .png files I created in Photoshop to generate the animated brushes. As you can see in the attachment, the random scattered apples have these artifacts all around, while the coins I created earlier look just fine. Is there some option or knowledge I am missing? I really like the use of animated brushes and would be grateful for any help.
Thanks in advance
Jan
RE: Getting weird pixel artifacts when using animated brushes - rich2005 - 09-19-2021
This has been reported as a bug and it looks like no fix. https://gitlab.gnome.org/GNOME/gimp/-/issues/3686
It seems to be caused by a sub-pixel rendering effect, the paint tool brush is not aligned with the pixels grid. You can also get this effect using a brush and a dynamic where the brush is rotated when painting.
RE: Getting weird pixel artifacts when using animated brushes - Jan Thümmler - 09-19-2021
Aw dang.
Thanks for your answer. So is there a way to create brushes form scratch that are aligned with the pixels grid? I am already using a dynamic with rotation, so is the issue with the animated brush then? I'll try to experiment further, but i really like the use of multiple, randomly selected images for the brush.
[EDIT: I found a somewhat satisfying solution, thanks to your suggestion about using the regular brush, thanks a bunch!]
RE: Getting weird pixel artifacts when using animated brushes - PixLab - 09-19-2021
(09-19-2021, 10:34 AM)Jan Thümmler Wrote: [EDIT: I found a somewhat satisfying solution, thanks to your suggestion about using the regular brush, thanks a bunch!]
Can you please tell us more about this solution?
I got a kind of same problem with with my "on the fly" brush (Select/Copy, then use the "Image clipboard" brush), is it about number of pixels or size? or something else?
I'm very curious about your solution even if it a quoted "solution"
RE: Getting weird pixel artifacts when using animated brushes - rich2005 - 09-19-2021
As long as you get some solution that works with your images.
Just a note, stole some of your apples, this a comparison between a RGB gih brush and the same as a grayscale gih. No artifacts with the grayscale brush. Obviously not much use for apples but might come in handy sometime.
[attachment=6713]
RE: Getting weird pixel artifacts when using animated brushes - Jan Thümmler - 09-19-2021
(09-19-2021, 11:29 AM)PixLab Wrote:(09-19-2021, 10:34 AM)Jan Thümmler Wrote: [EDIT: I found a somewhat satisfying solution, thanks to your suggestion about using the regular brush, thanks a bunch!]
Can you please tell us more about this solution?
I got a kind of same problem with with my "on the fly" brush (Select/Copy, then use the "Image clipboard" brush), is it about number of pixels or size? or something else?
I'm very curious about your solution even if it a quoted "solution"
Well, I just created several normal brushes with just one image as the base and then mix them together to get the variety I want. Works most of the time (sometimes I still get artifacts, seems to be depending on the base image. Weird stuff, it would be so awesome if i could just scatter multiple images all over the place.
(09-19-2021, 11:29 AM)rich2005 Wrote: As long as you get some solution that works with your images.
Just a note, stole some of your apples, this a comparison between a RGB gih brush and the same as a grayscale gih. No artifacts with the grayscale brush. Obviously not much use for apples but might come in handy sometime.
OK interesting. I still have much to learn about GIMP ^^
RE: Getting weird pixel artifacts when using animated brushes - Ellye - 02-18-2024
(09-19-2021, 08:24 AM)rich2005 Wrote: This has been reported as a bug and it looks like no fix. https://gitlab.gnome.org/GNOME/gimp/-/issues/3686This bug is seriously affecting the progress speed in my current project.
It seems to be caused by a sub-pixel rendering effect, the paint tool brush is not aligned with the pixels grid. You can also get this effect using a brush and a dynamic where the brush is rotated when painting.
From the issue tracker there, there seems to have been no fix on the 3+ years, right?
Is there a known work-around for it? Downgrading to 2.8 isn't really an option for me.