Write to and serialize the resource_manager database

[Drakulix]

I unfortunately have a use-case in smithay for setting Xft.dpi.

Given the resource_manager module docs say..

Please open a feature request if you need something that is not available.

..I thought I might as well create an issue. Maybe @psychon has some draft code laying around somewhere.

If not I would love some pointers on how to best tackle implementing this.

[psychon]

Maybe @psychon has some draft code laying around somewhere.

Sorry, nope.

If not I would love some pointers on how to best tackle implementing this.

Uhm... std::process::Command("xrdb").args(["Sorry, I do not actually know how to use this"])? ;-)

Alternatively, I would say: Look at the unit tests in x11rb-protocol/src/resource_manager/parser.rs for parse_database and learn how this xrdb stuff works. Then... implement something based on that. From a quick look, serialising things might not be too complicated, but I'm not really sure.

Also, once one has a string representation of the database, I am not entirely sure what to do with that. Looking at x11rb/src/resource_manager/mod.rs, one option is to set the RESOURCE_MANAGER property on the root window. But the API docs suggest that writing to ~/.Xdefaults or ~/.Xresources might work as well...?

Note that loading and then serialising is a lossy operation. This stuff supports #include, so arbitrary files are involved. Oh and there are comments that can be lost.

Another, quick hack idea would be: Load the RESOURCE_MANAGER property of the root window. Prepend or append \nXft.dpi: 42\n. Write out the resulting value to the property. See x11rb-protocol::resource_manager::Database::GET_RESOURCE_DATABASE for details on how the property is apparently meant to look.

[Drakulix]

Uhm... std::process::Command("xrdb").args(["Sorry, I do not actually know how to use this"])? ;-)

I have been thinking about that...

Also, once one has a string representation of the database, I am not entirely sure what to do with that. Looking at x11rb/src/resource_manager/mod.rs, one option is to set the RESOURCE_MANAGER property on the root window.

Given this value would be temporary and dynamic that seems like the sanest approach to me. (I hope toolkits monitor this property...)

Note that loading and then serialising is a lossy operation. This stuff supports #include, so arbitrary files are involved. Oh and there are comments that can be lost.

Not really an issue, if I am just looking at the RESOURCE_MANAGER-prop, I guess.

Another, quick hack idea would be: Load the RESOURCE_MANAGER property of the root window. Prepend or append \nXft.dpi: 42\n. Write out the resulting value to the property.

That doesn't really work for updating it though. (Yeah I could do a string match... but at that point I might as well implement it properly.)