Transform tool produces white artifacts around the edge of transformed result

Develop Artists Feedback & Testing
1

It has been happening for a long time in Krita and also in 5.0 beta nightly builds.
I’m writing this to see if there’s anyone has any workaround. :confused: I’ve already written a bug report but it’s so painful to use this rn lol

It seems only happen with Free Transform when it’s in Bicubic and Lanczos3 filter modes, and it always happens with Liquify tool(on the edge that I didn’t even touch)

STEPS TO REPRODUCE
Free transform :

  1. Make a colored layer.
  2. Select a part and copy paste it to a new layer.
  3. Transform the pasted layer, and make sure that the filter is in either Bicubic or Lanczos3.

Liquify transform :

  1. Make a colored layer or open any image.
  2. select any area and use liquify somewhere, but leave the rest of the edges untouched.
  3. Apply.

Result :

krita_YwztoBNuno
krita_YwztoBNuno747×683 1.37 KB

2

I don’t see either of those effects happening with the Sept 07 5.1.0-prealpha (git c34330b) appimage on Debian 10.

3

I cannot reproduce either on Windows 10 with Krita 4.4.8 and Krita 5 Beta 1.

Michelist

4

Do they still appear after you make the layer invisible, then visible again?

5

That’s weird, because it clearly is happening here. (Using the latest nightly)

Here’s the recording. :
https://imgur.com/Flx93Jk

And no it’s not a cosmetical problem. It affects the actual layer.

6

Okay, I see. Maybe it is due to the selection not being sharp it makes it semitransparent edges?

7

I can reproduce this issue in the beta with freehand selections regardless whether it’s a pixel selection, vector selection, or anti-aliased pixel selection.

8

I mean why is there gotta be ‘opaque’ ‘white’ artifacts around the edge anyway;

And it also happens with rectangular selections.

9

Does it happen if you use Cut (sharp) method from the Edit menu? Also after you do this and then make color the layer underneath black or some other very different color, is the edge semi-transparent light grey (which means the color from that layer with show through) or opaque white (which means it would be just white)?

10

1 Sharp cut seems irrelevant. It happens when transforming it.
2 The freehand transform seems to produce opaque edges, and the liquify seems to produce transparent lines that the layer underneath shows through. But I’m not sure they have the same culprit and just appear differently due to the transforming method.

11

I’ve had a better look and paid more attention:
It happens with a rectangular selection for vector and raster whether anti-aliased or not anti-aliased.
It happens for skew and rotation. i.e. if vertical or horizontal boundary becomes non-vertical/horizontal.
The artifacts are just inside the transform bounding box and seem to be a paler version of the main colour.

With the Liquify transform, for a large size and repeated rapid movements, there is sometimes tearing that is permananent and a small region becomes transparent:

Liquify Tearing
Liquify Tearing715×525 285 Bytes

12

I did a basic move with no other transformation but here is with the selection intact:

It definitely seems to outline the opaque. And cut sharp doesn’t do anything, it even does that with copy sharp into a new layer.

image
image1481×744 6.19 KB

13

@KnowZero ia this a screenshot? If so, do those artefacts remain in a saved image?

I ask because the dark outline looks like it might be thinner than the pixels in your canvas, which would make it a rendering bug of some kind. I get that kind of issue sometimes with some zoom levels.

14

I saved as a kra, closed and reopened and it remains. The issue seems to be the bicubical filter as other filters work fine.

15

@KnowZero what I mean is, if you export as a jpeg or other non-layered format, do the artefacts remain?

16

It is just how krita works though.

17

Exporting to PNG they remain.

18

OK, thanks. Looking at the image now on my PC, I realize what I thought was an outline artefact is actually the selection outline. I was on mobile before and couldn’t see well enough on the scaled-down version. Sorry to bother you!

19

no problem, it doesn’t hurt to do a few extra tests to be sure there is no obvious oversight.

And yes, I intentionally included the selection and the artifacts so it can be seen clearly.

20

Bicubic and Lanczos3 do tend to create a pale line on the inside of a region border as can be seen in the Resize operation when using these filters.
The tooltip for Lanczos3 actually warns you, “May produce aerials”.

I believe they’ve been designed to give ‘nice looking’ pictures with less consideration about what happens at the edges.

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