Color smudge brush's ratio setting bug (with video evidence)

[Y.H.Lai]

There was a thread about color smudge brush’s banding issue. After some tests, I’m now 99% sure it’s actually a bug.

Reproducing steps:

1. Select the default Wet Paint brush.
2. Paint. It works normally.
3. Set brush’s ratio to a lower number.
4. Set brush’s ratio to the original value (1.00).
5. Paint. Now it works differently from step 2!
6. Reset the brush.
7. Pain. Now it works the same as step 2 again.

Note that step 3 and 4 are simply to change a setting to a lower number, and change it back. There is absolutely no reason it’d change the brush’s behavior, right? But it just does. Therefore I think it’s a bug.

Please check the video.

Krita color smudge bug

Using Version: 5.0.0-beta2 (git a642eb0).

I haven’t report to bug tracker because I want to see if others’ have the same issue, and if there is something i missed.

[Lesqwe56]

Did some simple test on 5.0.0-beta2-e650032da0 with i)Wet Paint and can confirm this.
tested on 5.0.0-beta2-e650032da0

Also tested on 4.4.2 (android), seems behave as expect.

[tom]

I’m pretty sure this isn’t related to banding and is just some variation of this 5.x resource management bug: 441350 – Brushes works wrong, after selecting another pattern and reselecting the original one, they works like the should

Wet Paint, the brush you’re using as an example, has some bug related to loading its pattern when brush settings are changed. Notice how the behavior you demonstrate no longer occurs if you disable the pattern option.

If you want to curtail banding, I recommend using the new Smudge algorithm option (as of 5.0) under Smudge Length, which will eliminate most of it. Currently most (if not all) smudge brushes included with Krita use the old algorithm.

[Lesqwe56]

I see, changing setting will reapply the pattern, while reset brush the pattern will be dropped.

[Y.H.Lai]

You’re right. Doesn’t happen with brushes without patterns. It’s a different bug then.

@tom

If you want to curtail banding, I recommend using the new Smudge algorithm option (as of 5.0) under Smudge Length, which will eliminate most of it. Currently most (if not all) smudge brushes included with Krita use the old algorithm.

I’m not so sure… It’s Wet Paint. First of all I disable the pattern. Then I checked new smudge algorithm, the it became very opaque and completely different from the original Wet Paint. I read a bit of the official doc about the new algorithm, figured that it’s probably better to enable Color Rate’s pressure sensitivity.

Then it gets the transparency I want… with the banding I were trying to avoid at the first place.