lepr

you're welcome

Instead of copy and paste, press cmd-j to duplicate.

You: "In passthrough [...] when you change the group gamma, too this gets ignored and has no impact." Me: "[...] the blend gamma of a Passthrough Group does have an affect [...]" My statement contradicts yours.

All three bullet points contain garbage. The author either doesn't really understand that aspect of the software, or they are very unskilled at communicating their knowledge. The third bullet point will be referring to the trick of using a Multiply mode white fill layer at the bottom of the layer stack inside a Passthrough mode group.

In RGBA/8 and RGBA/16 documents, the blend gamma of a Passthrough Group does have an affect if you ensure there is an actual layer/object below the Group and not just the canvas. This thread has become a mess of poorly controlled experiments or ideas being posted as facts without actual testing which easily proves the ideas wrong.

If a high impact issue remains unfixed for a decade, there is absolutely zero prospect of a medium impact issue being fixed.

The preview ignores the actual choice of Output ("Selection" in your case) and shows the result for "New layer with mask", which involves edge decontamination.

Leaving aside RGBA/32 documents where Blend Gamma is ignored and RGB values are used "as is" in blending, the following concerns RGBA/8 and RGBA/16 documents. The upper layer's Blend Gamma value is factored in, yes, and I did not assert the opposite. However, your claimed linearisation of upper and lower layers before blending and then gamma encoding of the blending result is not performed, and that's why your spreadsheet does not give the same results as Affinity. The upper and lower layer's RGB values are exponentiated by (2.2 / upper Blend Gamma) before blending, and the blending result's RGB values have the inverse exponentiation applied to them. The measured results in Affinity verify that, allowing for decimal rounding errors. Notice that that implies no exponentiation happening in the case of the default Blend Gamma 2.2, and the measured results in Affinity verify that the RGB values are used "as is" in that default case. Contrast that with your assertion that, in the case of Blend Gamma 2.2, RGB values are exponentiated by 2.2 before blending, and the blending result's RGB values have the inverse exponentiation applied to them. The measured results in Affinity prove that wrong.

Simple solution with no tweaking nodes, expanding strokes, merging shapes, filling holes etc.: leave the strokes fully opaque and just reduce the opacity of the Group in the Layers panel. shadow.mp4

My response to you just 8 weeks ago:

NotMyFault's calculations do the blending with gamma-decoded RGB values, but Affinity does the blending with gamma-encoded RGB values.

Opt/alt click to select an object that is behind the text frame.

You can in Photo and the Photo Persona of Publisher... Layer > New Group

If a Layer is a "Layer layer" then a Pixel Layer must be a "Pixel Layer layer"

Maybe Affinity 3 will have Layer layer layers. Can we have Group group groups to go with that, please?