Bug 413582 - Squiggly brush stroke when painting in zoomed out canvas
Summary: Squiggly brush stroke when painting in zoomed out canvas
Status: RESOLVED INTENTIONAL
Alias: None
Product: krita
Classification: Applications
Component: Brush Engine/Shape (show other bugs)
Version: 4.2.7.1
Platform: Other Microsoft Windows
: NOR normal
Target Milestone: ---
Assignee: Dmitry Kazakov
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2019-10-29 08:51 UTC by kaplan
Modified: 2019-10-29 11:04 UTC (History)
2 users (show)

See Also:
Latest Commit:
Version Fixed In:


Attachments
Pic of squiggly brush strokes (307.40 KB, image/png)
2019-10-29 08:51 UTC, kaplan
Details

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Description kaplan 2019-10-29 08:51:36 UTC
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.
Comment 1 Halla Rempt 2019-10-29 08:53:15 UTC

*** This bug has been marked as a duplicate of bug 413085 ***
Comment 2 Halla Rempt 2019-10-29 08:53:40 UTC
We were right now discussing this on irc, and Dmitry is working on it, but the bug had been reported before.
Comment 3 Dmitry Kazakov 2019-10-29 09:11:15 UTC
Hi, kaplan!

Could you tell, what brush preset you used to get this effect?
Comment 4 Dmitry Kazakov 2019-10-29 09:23:47 UTC
The bug is reported against 4.2.7.1, which doesn't have a patch causing bug 413085, so let's reopen it
Comment 5 kaplan 2019-10-29 09:49:46 UTC
I was using basic 5 size brush. Brush smoothing set to basic
Comment 6 Dmitry Kazakov 2019-10-29 11:04:55 UTC
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 :(