Rectangular to Polar / Polar to Rectangular

[MAffinity]

Hello,

First of all I have to say thank you for doing an alternative to photoshop (and illustrator) it is more than welcome!

 

I am doing some 14k hdri panorama editing at the moment and found some things which unfortunately work not as well as in photoshop yet.

Maybe there is a way to fix them!?

 

The process:

To get rid of the tripod in the picture it is necessary to do some clone stamping. So what you do is flipping the image vertically and then use the rectangular to polar filter to unstretch the floor.

after clone stamping you use the polar to rectangular filter and flip the image vertically another time.

 

The Problems:

- after using the polar to rectangular filter the top of the image does a weird stretching (photoshop doesn't do that)

what I do to avoid this is just making a mask and only paint in the edited (clone stamped) parts.

 

Unfortunately the second problem is bigger:

- after using the polar to rectangular filter the image is unsharp and has a weird jpeg like artifact pattern.

 

First Problem (Stretching in the top of the image)

 

 

Second Problem (Unsharp Artifacts)

 

It looks similar to the artifacts in the following post:

https://forum.affinity.serif.com/index.php?/topic/16741-rectangular-to-polar-good-results/

 

Thanks!