NDE and sampling confusion.

[teapot]

Hi,

I'm confused by how tools that sample a layer interact with non destructive editing. An example:

On a new layer filled with white:
Draw three green circles making sure they don't overlap.
Filters -> Distorts -> Ripple un-merged.
Set the foreground colour to red.
With the bucket fill tool click on one of the green shapes.
The layer doesn't fully update right away, that's already got a bug report, so toggle the layer's visibility off and then on to trigger an update.

What happens is the ripple is applied 'twice':
The bucket fill samples the layer including the visible un-merged ripple.
It writes the result of the bucket fill to the layer, this includes the ripple.
The un-merged ripple is still being applied to the layer.
The result is the whole layer is rippled twice even though all we did was bucket fill one of the three shapes.

I tried this in 3.2.4 and 3.2.6.
Is this expected behaviour?
If not what should it do and has it been reported?

[forum6c04a3e1]

For your GIMP 3.2.4/3.2.6 example on Linux, I would separate the sampling question from the delayed redraw: save a copy of the XCF, undo the fill, temporarily disable Ripple in the layer's Fx list, then repeat the fill with Sample merged off. Re-enable Ripple afterwards and compare with the original result. That gives a useful control without baking the filter into the source pixels.

The manual defines Sample merged as sampling all visible layers; it does not promise that switching it off excludes the active layer's live filters: https://docs.gimp.org/3.0/en/gimp-tool-bucket-fill.html

I cannot confirm whether this exact double-Ripple case is already reported. A small XCF plus the Sample merged setting and the control result would help distinguish it from the separate redraw bug.