Hello JK,

There are some bitmap filters in XDP X11 (and some earlier versions, and perhaps limited to the 32-bit version) that more or less can warp the image to force the horizon into a more circular shape. I wasn't happy with my attempts.

One of the screen shots below are using an image editor, the other can be done using any application that has mesh warping capability (I used a layout application, actually).

Click image for larger version.  Name: Capture-000066.png  Views: 143  Size: 81.9 KB  ID: 111737

Click image for larger version.  Name: Capture-000067.png  Views: 135  Size: 160.0 KB  ID: 111738