Yes, very close, but two of the corners suggest walls where I'd have a continuous curve.
I really thought I had it figured out. I could hardly wait to get home and try it.
Imagine a grayscale island scene floating in a transparent land-locked sea in a land of white.
Bleed the edges of the grayscale half the distance to the land.
Bleed the edges (or more simply, bucket fill the remaining half-distance with white.
Select the "band" defining the sea.
Gaussian blur half the width of the sea.
It should've worked, but I end with an artifact from the bleed which also shows up in the
subsequent gblur. But this is tantalizingly close. (The artifact appears to bevel the
otherwise-continuous image.)


Still have to try it on the square-to-round, but in my application both the island and the sea will
be similar shapes. [EDIT: sqr2rd showed same artifact, but otherwise the idea has merit.]
I shouldn't give the impression that this an artifact of the Bleed script, but rather an artifact of my coercion of the
Bleed script where I ought to be using a copy tool to "grow" the edge colors (like perhaps StepResizeKeepingLayers).