Smudge Tool

[Arragon]

It would be nice if you could add

• Protect Alpha (like Paint Brush Tool)
• Source [Current Layer/Current Layer & Below] (like Inpainting Brush Tool)
• Strength Scatter (in Brush Settings)

for the Smudge Brush Tool

[carl123]

4 hours ago, Arragon said:

Protect Alpha (like Paint Brush Tool)

If you go to the Channels studio and untick the Editable icon (looks like a pen/pencil) next to Composite Alpha does this do what you want?

[Arragon]

7 hours ago, carl123 said:

If you go to the Channels studio and untick the Editable icon (looks like a pen/pencil) next to Composite Alpha does this do what you want?

There is no Channels studio in Affinity Designer.  In Affinity Photo this would work.

[carl123]

Ah, totally forgot that Designer has a smudge tool

Make a copy of the layer 
Moved it to the clipped positioned on the original layer i.e. horizontal blue bar position (not the masked position)
Use smudge tool on the clipped (duplicated) layer not the original layer

See if that does what you want