fulla -s switch should add alpha channel

[Bruno Postle]

I tried creating a nona wrapper that called fulla to correct tca before each remapping, this didn't work because:

1. the default is to scale the channels to avoid missing edge pixels, this changes the FoV and messes up the stitch.

2. the -s switch turns off this scaling, but the off-colour edge pixels mess-up blending with enblend/enfuse.

The -s switch should introduce 100% transparency where there is missing channel data, this means that the photos would retain their field of view and could still be used as input for nona.

[Gerry Patterson (gpatters)]

From what I can tell, fulla currently does not support loading images with alpha channels. At least not when I try using a png or tiff with an alpha channel. Not to say it couldn't be updated to support images with alpha channels, just wondering if this was intentional.

- Gerry

[Gerry Patterson (gpatters)]

More investigation.

Fulla will output the same type of image that is passed as in as input. As such, some input image formats do not have alpha channels, jpeg for example, a conversion on output to another format that supports alpha channels would be required. This is what nona does, for example. Pass nona a jpg and it will put out a tif with an alpha channel.

Do we want to change fulla to always output tifs no matter what the input is?

- Gerry

[Bruno Postle (brunopostle)]

It is a bug if images with alpha channels can't be loaded, e.g. it ought to be possible to run fulla on exposure stacks fused by enfuse.

It would be no problem forcing TIFF output. Alternatively the alpha channel could be discarded for JPEG output and kept for TIFF and PNG.

[Yuv (yuv)]

I would prefer not to force TIFF output. keep the alpha for TIFF and PNG; discard for JPG would be great.

[Rich (rpow5152)]

Thanks for trying to implement this capability.
It would be a great boost to workflow to have TCA occur at the remapping stage.
I wonder if scaled FoV values could be passed to enblend / enfuse to compensate for the TCA changes. The positions yaw, pitch, roll don't change even if the scaling does.

[tmodes (tmodes)]

Support for alpha channel implemented in changeset ce270979a21a