Add Layer Swapping option

[NickKnatterton]

Hey there,

I´ve noticed that with the newer versions and more complete checking, the plugin does not allow to import a layout when the number of layers is different between the projects.
This of course avoids a lot of confusion (e.g. where did my layer go... ) but also seriously hinders the reuse of layouts across different boards.
I would propose to allow this kind of import based on user input.
For now just checking which layers were used in the source layout and simply matching them with the desired layer in the active project seems to work okay.
For a quick test I put a version working with KiCAD 6 on my fork, if you like the idea I will update and clean the code a bit and start a merge request.
I have not done too much of testing (e.g. mirrored or rotated imports etc..) but only made a first proof of concept.
There´s quiet some room for improvements e.g.
Checking for components (why not put the bottom layer on In6 if there are no components there?)
or allowing to discard certain layers (import from 6 layers board to 4 layers, but throwing away two less used layers and starting from there)

Any takers for this function?

Cheers,
Nik

[MitjaNemec]

This is a sensible feature although it would require quite some work. As you've seen with schematics hash check I try to put as many check in place as I can, to prevent the user shooting himself in the foot.

The basic functionality should cover the case where destination board has more layer than source and user can swap inner layer as he/she wants.
And then we come to exotic cases:

1. swapping inner layers with top/bot layers. There has to be a check to test if there are any footprints on said layer (and proper user notification
2. the source design has more layers than destination board. Here the user should have an UI option to select which source layers to disregard, but the plugin should check source layout if there were any items (drawings, tracks, zones) on said layer.

As you've figured already out, the restore part of the plugin has to be split. This should not be such a big issue. Bigger issues are handling of corner cases and abortion of the plugin operation when it finds them. This really fractures the code.

Before I would release such a feature I'd like to have a test in place so that I can test the business logic without the UI as it makes debugging much easier/faster.

And finaly I have to let you know that I am quite short on time and V6/V7 migration took some energy. In the short term I'd like to close the Replicate Layout issue 38. I currently have the replicate layout plugin architecture/code in my head and I am really not keen to context switching. Thanks for understanding