Hello !

First, I know that filters does not work on layer groups, it has been cited on krita-foundation tumblr : https://krita-foundation.tumblr.com/pos ... -at-once-i

Sadly, there are no explanations on why. So I can only guess : not a desired feature ? not a priority ? hard to implement ?

Second, I looked through the forum and used the "search" functionality, but couldn't find related topics, so here I go.

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In my daily workflow I use many layers (can go up to hundreds and more). These layers are grouped within layer groups. Whenever I want to apply a filter to a whole group I have to create a filter layer/mask on this group, adjust the filter to match my needs and confirm. A filter layer/mask is great since it is non-destructive and I can change the values later. However, most of the time I won't go back on these changes and the filter layer/mask adds computation to affected layers, slowing down painting process. To "apply" the filter on sub-layers, I have 2 solutions. The first one is to save filter parameters to a preset, then delete the filter layer/mask, apply the filter manually from the "filter" menu with the good parameters on one of the layers, then repeat on all other sub-layers with CTRL+F (Apply Filter Again). The second solution is to "flatten" the filter layer/mask then cut-paste to every sub-layers.

I mostly use the first solution which is faster. However, many times I felt the need for a way to "automatize" this process. It really depends of the stage of the painting but I can have to repeat the operation once every hour.

Of course, I don't want to merge my painting layers because I want to preserve the "Alpha locked" option.

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I don't know if other people would need this, but I don't feel like my usage of Krita is awkward. It's not the most time-consuming operation but it tilts me every now and then, so I had to share.

If you're a developer and this feature have already been discussed, please forgive me and please link me the discussion because I cannot find it.
If you're a Krita user, please share your point of view.

Thank you !

Layer groups have two modes: normal and pass-through. In pass-through mode, there is nothing to filter. In normal mode, the "contents" of a layer group is calculated from all the layers it contains: that's called the projection. If you'd apply a filter destructively to the projection, then next time something changes in one of the layers in the group, the projection is recalculated and you will have lost the effect of the filter.

Of course we could keep the filter parameters around and re-apply the filter once the projection changes, but... That's exactly what a filter mask does. And as long as you don't change anything in the layer group, there's no extra computation hit for the filter mask, because Krita just uses the filtered projection when calculation the project of the whole layer stack.