Feathering and the "marching ants"

When I make a selection, I see the "marching ants" where the selection is. If I grow/shrink the selection, I see the "marching ants" where the selection ends up.

When I choose to Feather, it looks like the "marching ants" do not display the correct placement of the selection. For example, I start with this round selection on a tag :

If I add a Feather to that selection, the "marching ants" show a smaller selection:

That gives the impression that the selection is smaller than the original. However, if I fill that selection, it shows that the color extend the "marching ants" so I am getting an inaccurate representation of how much feathering I would actually need to achieve the result I want.

Is that the normal and expected behavior on how the Feathering is displayed?

To me, it looks completely opposite of what I would expect. In this format, I have no clue how much feathering I would need to stay within the dimensions of the tag, for example.

I am using V3.0.3 on Windows 10 if it makes any difference.

Quote from Old Bruce

I think that the marching ants show the point where the opacity (feathering) is at 50%, not the extreme outer bounds which would be a fraction of 1%, nor at the minimum where the opacity would be at 100%. I could be wrong about the cut off being 50% opacity.

Maybe so, but is there a way to know how far the selection is? It does not make sense to have only a partial "image" of the selection area.

Is there another way to get that?

Quote from walt.farrell

Refine the selection; e.g., by pressing Q.

That is a bit convoluted. I see that it shows the feathering, but then I lost the marching ants that SHOULD tell me where the max feathering would go. It is still a "guessing game"

Now, once I fill that selection, I MIGHT still have to readjust this and undo it.

In fact, if I check where the color was added with the Flood select tool, I can see that the feathering extended past the edges of the circle tag:

In the end, what is the purpose of the marching ants? How can i really visualize where the selection is? Is it not possible and I have to guess?

Quote from smadell

If you make your selection and apply a feather, you can visualize the feathered selection (the “end result”) by turning on the Quick Mask. Pressing “Q” will do this. While the QuickMask is active, switch to the Move tool and you can adjust the size and position of the selection. If I remember correctly, the selection is defined by a bounding box with handles that can be used to make the selection (including the feathering) larger or smaller.

Yeah, I see that, but it is so convoluted! Thanks for this alternative.

Quote from smadell

Convoluted, yes. But I think it is fairly standard among editing software apps for marching ants to delineate areas that are 50% or more selected. When you create that initial selection, it probably has a sharp border because the active selection is all 100% selected. Once you feather the selection, the “border” of the selection becomes harder to define (in a practical sense). Hence, the confusion.

When feathering a simple selection, there is a reasonable argument to be made for drawing the marching ants at the absolute border rather than at the 50% mark. However, consider making a selection based on luminosity or based on a channel, or some other range. Any range-based selection would have to draw the marching ants somewhere or else the entire document would be surrounded by marching ants at its edges, rendering the drawing of them useless.

I don't know about other programs, but I have used PaintShop Pro for 15+ years and it does show the edges of the selection. Visually, it seemed logical, so this approach is very odd to me. I thought that maybe there was another way to visualize the edges clearly. I guess not.

Quote from walt.farrell

Sorry; I don't understand that comment.

Flood Select is going to make a different selection. How does that relate to your current selection?

Yes, it made a different selection. I just wanted to test how far the filling of the color in the feathered selection did go. Just looking at it, I was not sure if it was extending past the tag edge or not, but that just indicated that it was extending further.