Bug 422373

Summary: Jagged brush lines
Product: [Applications] krita Reporter: Sylvester <localkd>
Component: GeneralAssignee: Krita Bugs <krita-bugs-null>
Status: RESOLVED DUPLICATE    
Severity: major CC: ahab.greybeard, ghevan, halla
Priority: NOR    
Version First Reported In: 4.2.9   
Target Milestone: ---   
Platform: macOS (DMG)   
OS: macOS   
Latest Commit: Version Fixed In:
Sentry Crash Report:
Attachments: Example of the brush lag/jagged lines that I am experiencing
Example of stroke segmentation with Wacom tablet
reply w. attachment

Description Sylvester 2020-06-02 13:44:51 UTC
Created attachment 128998 [details]
Example of the brush lag/jagged lines that I am experiencing

SUMMARY

Hello-
I am not sure how to report bugs correctly, but I have found this a frustrating issue for years, so I am giving it a go.
I love Krita and have used it religiously for most of my digital art, but one thing that has been bugging me (no pun intended haha) is how I constantly experience lag with any of the brushes that come with the program. I am using the latest Wacom drivers and the Wacom Intuos Pro.
If I draw very slowly, I don't have much problems, but if I draw quick strokes, it seems that the brush engine is just simply guessing where the line is supposed to go, resulting in jagged and angular lines rather than one smooth line.
I have tried everything that I possibly could think of and have search the internet for answers, but with no luck as to how to fix this issue.
I've attached a screenshot as an example to what I mean.
It seems similar to a recent problem (about 2 years old) that people had found that the first part of a new line would do this "guessing/jagged/lag" thing, but I am experiencing this throughout the whole line.
I hope to hear back and that this may get fixed sometime in the future (?)- 
thank you so much for everything you do :)

- Syl


STEPS TO REPRODUCE
1. 
2. 
3. 

OBSERVED RESULT


EXPECTED RESULT


SOFTWARE/OS VERSIONS
Windows: 
macOS: Mojave 10.14.6
MacBook Pro (Retina, 13,3-inch (2560 x 1600), Early 2015)
Processor: 2,9 GHz Intel Core i5
Memory: 8 GB 1867 MHz DDR3
Startup Disk: Macintosh HD
Graphics: Intel Iris Graphics 6100 1536 MB

Linux/KDE Plasma: 
(available in About System)
KDE Plasma Version: 
KDE Frameworks Version: 
Qt Version: 

ADDITIONAL INFORMATION
Comment 1 Ahab Greybeard 2020-06-11 11:58:11 UTC
Created attachment 129229 [details]
Example of stroke segmentation with Wacom tablet

That type of stroke segmentation is seen with Wacom tablets and it's thought that they have a low positional report rate compared to other tablets.

I've attached a screenshot, comparable to your situation, using a Wacom Intuos Draw with the 4.2.9 Linux appimage.

The left side 'spiral' is done with Basic brush smoothing and the right side one is done with None brush smoothing. The regular segmentation due to low report rate is obvious but not too bad. I drew those at a very high speed.

In your case, the segmentation seems to be much worse and it not fully regular so there may be a driver issue or a performance issue .

Does using brush smoothing set to Basic help at all?
Comment 2 Sylvester 2020-06-19 12:50:14 UTC
Created attachment 129524 [details]
reply w. attachment

Ah, I see- I wish mine were even half as smooth as what you achieved!
I have attached an image showing me testing the basic stabilizer vs no stabilizer (none), and I don't seem to be getting any different results, unfortunately.

Thank you very much for your reply!
Comment 3 vanyossi 2020-06-19 16:31:44 UTC
This problem is caused by our openGL implementation on ancient apple openGL API. e are currently sutdying options to fix this as we know how frustrating it is to get it to behave. 

There are work arounds as see on the bug im marking as duplicated of, but they have drawbacks.

*** This bug has been marked as a duplicate of bug 414025 ***