Is there no way to center an elliptical selection?

[Stokestack]

42 minutes ago, firstdefence said:

With regard to the “smearing” effect or that the edge looks fuzzier as it gets bigger, this is probably because the feather parameter is being scaled

That's probably a pretty good guess. I'd argue that this is not the expected behavior. But, it may mean that the marquee can indeed scale gracefully if there's no feathering applied.

[Alfred]

23 hours ago, R C-R said:

The marching ants outline encloses an area where at least ½ of a pixel is selected.

Or rather, the marching ants outline encloses an area where the opacity of the pixels is at least 50%. If you make a pixel selection, all of the pixels are fully selected; if you feather the selection, all of the selected pixels remain fully selected but the opacity drops off at the edges of the selected region.

[R C-R]

2 hours ago, firstdefence said:

With regard to the “smearing” effect or that the edge looks fuzzier as it gets bigger, this is probably because the feather parameter is being scaled...
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Would be interesting to know if this is actually the case.

From what I can tell, it is scaled. I am just not sure what the reference point is for where the feathering begins. In the feather scaled.afphoto test below, the blue areas have no feathering applied & the top purple one has 50 px applied. The bottom ones are the results of scaling the selections to 2X.