Created attachment 123555 [details] Pic of squiggly brush strokes SUMMARY When painting in a zoomed out canvas the brush stroke becomes squiggly in comparison to working in a zoomed in canvas STEPS TO REPRODUCE 1. Create a 4K canvas with default settings 2. Let the canvas be at 25% and draw a zigzag line 3. Now zoom in to 100% and do another zigzaggy line OBSERVED RESULT The zoomed in stroke becomes way smoother and nicer around the edges in comparison to the zoomed out stroke. EXPECTED RESULT Shouldn't matter in what kind of zoomed in level I'm at, lines should be smooth at the edges of the brush. In the attached picture you can see a pink and blue line. The pink line was painted at a 25% zoom level, the blue line was painted in 100% zoom level.
*** This bug has been marked as a duplicate of bug 413085 ***
We were right now discussing this on irc, and Dmitry is working on it, but the bug had been reported before.
Hi, kaplan! Could you tell, what brush preset you used to get this effect?
The bug is reported against 4.2.7.1, which doesn't have a patch causing bug 413085, so let's reopen it
I was using basic 5 size brush. Brush smoothing set to basic
Kaplan reported on IRC that he used mouse to paint this test image. I have checked Qt's code and it seems like it is hardware limitation of the mouse protocol. Mouse event coordinates are always rounded to nearest integer. It means that at zoom 25% the stroke position will be rounded to every 4 pixels. Which basically generates such artifacts. And according to Qt's code, we cannot do anything about that :(