contrib: add python layout

[Leon-Plickat]

No description provided.

[ifreund]

This looks pretty neat, could I get a TLDR on how to get pywayland to scan the river-layout protocol so I can test this? Probably would be worth adding that to the comment at the top as well, similar to the build instructions for contrib/layout.c.

[Leon-Plickat]

TBH I have no idea how pywaylands scanner is supposed to work.

I got it to scan the protocol and generate bindings by copying it to /usr/share/wayland-protocols/river-layout-v3/river-layout-v3.xml and running this command once:

sudo python3 -m pywayland.scanner --with-protocols 

[Leon-Plickat]

@ifreund I have found out how to make the scanning work.

mkdir protocols
python -m pywayland.scanner -o protocols -i /usr/share/wayland/wayland.xml ../protocols/river-layout-v3.xml

The scanner finds wayland.xml automatically by default, but when using -i you do not add additional protocol files to scan, you bypass the automatic path finding. So wayland.xml apparently needs to be specified explicitly. Pretty unintuitive, but it works.

Now I only need to figure out how to make python import the local bindings.

[Leon-Plickat]

Ok, I give up. I don't think pywayland supports using local bindings. It seems like all bindings have to be part of the actual package, which means the only two options I see are either having a local copy of pywayland with the bindings, or adding the bindings to the global pywayland package.

The command to add the bindings to the global package:

sudo python3 -m pywayland.scanner --with-protocols -i /usr/share/wayland/wayland.xml river-layout-v3.xml

That command probably also works for local packages, sans the sudo, since pywaylands scanner apparently knows where the package lives. This is not documented however (the docs say the default output is ./pywayland/protocols, which is false).

[Leon-Plickat]

I added the instructions for generating the bindings into the layout. They will be automatically printed if importing the river-layout bindings fails.

If we don't find python wayland bindings that are nicer to use, this will not get any better than it is now I am afraid.

[Leon-Plickat]

Are there still any blockers, other than pywayland being unwieldy?

[ifreund]

Are there still any blockers, other than pywayland being unwieldy?

Nope, I just need to find time to deal with setting up pywayland to test.

[ifreund]

LGTM, Thanks!

[ifreund]

Note: I found that one can avoid running the pywayland scanner as root by using a virtual environment, which is a lot cleaner. I added a commit recommending this instead.

For example:

cd contrib
python -m venv fooenv
source ./fooenv/bin/activate
pip install pywayland
python -m pywayland.scanner -i /usr/share/wayland/wayland.xml ../protocol/river-layout-v3.xml
python layout.py