nona seam placement broken

[Bruno Postle]

I see this with a current snapshot using nona JPEG, PNG and TIFF output but not with TIFF_m, hence you won't see this bug if you are blending with enblend. Basically the internal seaming nona uses when creating a single output file appears to be broken.

How to reproduce: save a hugin project, open it up and change n"TIFF_m c:NONE" to n"TIFF c:NONE", then try and stitch it with `nona -o junk project.pto`.

(transferred from bug# 1960632, and setting to 0.7.1 as this won't be seen during normal hugin usage)

[tmodes (tmodes)]

Hugin is using now only enblend for blending.

[Felix Hagemann (flixh)]

cubic2erect from the Panotools::Script collection relies on nona as a stitcher to stitch nine (not-overlapping) cube faces to one equirect. Is this affected as well? It's the only free and easy cube face <-> equirect converter I know of, so I would be sad to loose it.

[Bruno Postle (brunopostle)]

This bug doesn't break cubic2erect as it probably already existed when cubic2erect was written.