One of the clever guys needed for advice, Hopefully Ofnuts will come along.
I looked at using the built-in Gimp color exchange when you first posted.
It looks to me like you are using linux (which distro ?). It might help if you post an example .xcf file.
I am no coder, I would normally use the BIMP batch plugin but that is no good with multi-layer .xcf files.
The Gimp 2.10 color-exchange uses GEGL. The exchange syntax is straight forward but I can not get it to recognize a color, either in GEGL-graph or a plugin.
You might want to consider falling back to the old Gimp 2.8 compiled exchange plugin. On the simplest level, a python plugin, with encoded layer positions, might work like this in Gimp 2.10: https://i.imgur.com/hujMEzL.mp4
I have no idea how that gets wrapped in a Gimp batch command.
I looked at using the built-in Gimp color exchange when you first posted.
It looks to me like you are using linux (which distro ?). It might help if you post an example .xcf file.
I am no coder, I would normally use the BIMP batch plugin but that is no good with multi-layer .xcf files.
The Gimp 2.10 color-exchange uses GEGL. The exchange syntax is straight forward but I can not get it to recognize a color, either in GEGL-graph or a plugin.
You might want to consider falling back to the old Gimp 2.8 compiled exchange plugin. On the simplest level, a python plugin, with encoded layer positions, might work like this in Gimp 2.10: https://i.imgur.com/hujMEzL.mp4
I have no idea how that gets wrapped in a Gimp batch command.