Random brush strokes in Affinity Photo

[DamienM]

Hi all,

New user here, I've been trying to understand a quirk that seems to happen with Affinity Photo when painting.

Basically, at random times, the brush seems to "hitch" and randomly give me a straight line while I'm painting. I've recorded a short video so you can see what I mean. Notice how I am just going around in a circular motion with the brush, and random hitches occur where the brush glitches and creates a straight line between points (and no I'm not touching the shift key when I'm doing this).

 

Any advice on what's going on here would be great. I've tried turning on/off the acceleration, tried different settings for the video card, nothing seems to get rid of it.

Edit: I've noticed it's mostly short-stroke brush movements, it lags heavily and causes a lot of straight lines, lag, and general non-function when doing rapid brush strokes. It's actually pretty unusable. I've tried mostly everything, even tried single-screen, Wacom double click turned off, lowered the resolution to try to make it faster, etc. I'm running a pretty high last-get Intel iMac, everything else runs smooth as butter (and longer, continuous strokes can go on forever without any lag, it's really just the short and fast ones).  It does this even on a basic brush, no additional effects, nothing special, default brush. It also does this when I try it using the apple Magic Mouse and not the tablet.

Basically this makes the program useless for painting, I really would like it to work but seeing some older forum posts makes me worry this is just how the program acts and can't be fixed? I hope someone has a solution. Thanks in advance.

Edited June 8, 2024 by DamienM

[BlueLiner]

Pen or mouse? I tried to recreate this with v2.5.2 (Win 10 Pro) and various brushes using my mouse. My pen is at my office so I cannot try that. I was unable to recreate your results. I could get some of my more unusual brushes to act a little odd by messing with the flow. Nothing though like what you are seeing. What about other brushes? If so, what about basic brushes? Try turning wet edges off if on and see if you can recreate.

I wish I could be of more help.

[walt.farrell]

A straight line could indicate that you've pressed the shift key, or the system thinks you have.

[DamienM]

Hey guys,

 

Reviving this because as I mentioned in my earlier post; I am not using the shift key (and no other program thinks I have it pressed), I'm using a pen/tablet, and for some reason this only happens on my Intel iMac. My M1 Mac mini does not have this problem. As I mentioned earlier, I've tried a few things in my original post, nothing seems to be getting rid of the pen lag on quick strokes and the strange glitching I am getting. 

 

Any more thoughts would be appreciated, thanks :)