Can a rendered frame be made seamless, by some compositor tricks? What I'm looking for is something similar to the GIMP filter Make seamless.
Here's an example
Original (downloaded from Pixabay):
I could, of course, do this in GIMP, but I'd like to avoid post processing in external applications, and get a ready made image directly out of Blender. My goal is to have a repeating background and composite non-repeating text on top of it, and I'd like to be able to do it with two render layers or, if necessary, two scenes in the same .blend.
When searching Blender.SE, I found several questions about seamless images, but they all seemed to want to know how to use pre-existing seamless images, or how to get a texture to repeat seamlessly on an object. The ones I actually opened, did not answer my question, since I'm aiming to create a seamless image from a render.