Way to limit selection to non-transparent part of layer quickly?

[AffinityType]

I am trying to select a image that has transparency on a layer, but can't figure out how to do it outside of the flood select tool. In PS, I can draw a rectangle around an image floating on a layer, then press Ctrl-Right arrow to nudge it one pixel right, the Ctrl-Left arrow to move it back into place, and the rectangle will disappear and leave me with only the non-transparent part of the image selected. Is there a way to do this in Affinity?

Edited January 12, 2021 by AffinityType

[carl123]

You query is a bit vague, so I'm not sure I understand what you want to do exactly but have a look at the 3 options under...

Select > Alpha Range...

To see if they do what you want

[Joachim_L]

Is the option activated marked in the attached image? On windows you can move it simply with the arrow keys (or the Shift modifier).

Darn, carl123 was faster, again. Plus it seems to be, that I did not understand the question.

[carl123]

You can also try CTRL+Click on the layers thumbnail in the layers panel