Quick, Successive Brush Strokes Lagging in Affinity Photo

[HOOman]

Hi there, I’m experiencing an issue with quick, successive brush strokes (tested with basic 4px brush using paint brush tool) like crosshatching in Affinity Photo on a 10k x 10k(px) 300dpi canvas that are very laggy.  I’m on a 2019 27” iMac (i5 9600K, 64GB memory) running macOS Big Sur 11.5.1, both Affinity Photo and Affinity Designer 1.9.3 and Affinity Photo 1.10.0.251 RC2 have this problem, I didn’t test it with Affinity Designer beta.

I don’t use a “high-end” pointer device with high polling rate (Logitech MX Master 3, max polling rate 133Hz on Bluetooth according to specs) like one of the FAQs suggested, and this issue can be mitigated by either reducing the size and dpi of the canvas (tested with 1000x1000px 72dpi), or disable the “Enable Metal Compute Acceleration” option in settings, but that makes brushes lag and stutter as expected.

I’ve attached a screen recording to show the lagging with quick brush strokes and how it works very smoothly when drawing a long, single line.

[Lee D]

Hi @HOOman Welcome to the forums.

Have you tried doing the same workflow, just without using the Logitech MX Master 3, just either a standard Apple Magic Mouse or a standard wired mouse. As I run a very similar spec iMac to yours (little less memory) but with a standard wired mouse or Apples Magic Mouse I don't get no brush lagging issues in any Affinity app (release & beta). It's worth checking to see if the issue can be narrowed down at all.

[HOOman]

I find it strange too for this to happen.

I’ve personally tried it with Apple Magic Trackpad 2, wired mouse (like you mentioned), Wacom Cintiq Pro 24, Huion Kamvas Pro 16 Plus 4k, they all exhibit the same behaviour, and my iMac was recently fully wiped (all partitions wiped from disk utility in recovery) and reinstalled, can’t think of anything else that would cause this to happen.  All my other drawing apps behave normally like Photoshop, Corel Painter, Rebelle and Clip Studio Paint.

[HOOman]

On 8/4/2021 at 10:46 PM, Lee D said:

Hi @HOOman Welcome to the forums.

Have you tried doing the same workflow, just without using the Logitech MX Master 3, just either a standard Apple Magic Mouse or a standard wired mouse. As I run a very similar spec iMac to yours (little less memory) but with a standard wired mouse or Apples Magic Mouse I don't get no brush lagging issues in any Affinity app (release & beta). It's worth checking to see if the issue can be narrowed down at all.

I tried a few different other things and it seems that with hardware acceleration enabled, it's the canvas size that dictates whether fast brush strokes would lag, it starts to show around 12.5k pixels and become noticeable at 13k pixels in any combination of page width and height, DPI doesn't seem to make any difference nor does colour format (RGB8/16/32).

I guess I can't quite ditch Photoshop yet, let see if the situation resolves itself with an M1X or M2 Mac.