Bug 434182

Summary: Masked brush not limited to area of brush tip stamp
Product: [Applications] krita Reporter: rebuilderster
Component: Brush enginesAssignee: Krita Bugs <krita-bugs-null>
Status: RESOLVED INTENTIONAL    
Severity: normal CC: griffinvalley
Priority: NOR    
Version First Reported In: 4.4.2   
Target Milestone: ---   
Platform: Mint (Ubuntu based)   
OS: Linux   
Latest Commit: Version Fixed/Implemented In:
Sentry Crash Report:
Attachments: Demonstration of masked brush unexpected behaviour.

Description rebuilderster 2021-03-09 10:41:32 UTC
Created attachment 136521 [details]
Demonstration of masked brush unexpected behaviour.

SUMMARY
When painting a complex stroke that passes near itself, the masked brush will affect the portions of the stroke laid out before, even though the main brush tip does not touch that area. See attachment for demonstration.

STEPS TO REPRODUCE
1. Create a basic brush with size controlled by pen pressure
2. Under masked brush, select a textured stamp, making sure it is at least as large as the max size of the brush tip.
3. in a single stroke, with low-to-medium pressure, draw a thin "U" so that the stroke passes near itself.

OBSERVED RESULT

The part of the stroke already laid down darkens as the stroke passes near itself. It seems the brush stamp is first applied, then the masked brush is applied to the resulting stroke.

EXPECTED RESULT

The masked brush should apply to the brush stamp before being applied to the canvas.
Comment 1 wolthera 2021-03-09 10:48:24 UTC
This is expected behaviour and is what makes the water-color mimicking brushes work at all.