Simple example for atspi/unix?

[C-Loftus]

Thank you for the great work on accesskit

I was trying to investigate contributing a simple quickstart example for unix with atspi since I am reasonably familiar with atspi itself, but can't seem to figure out how to get the unix adapter working.

The code at the end of this issue compiles and prints fine to stdout but Orca does not speak the announcement and I do not see any accessibility info in the acceserciser GUI on Linux.

I am on Ubuntu 24.04 with Orca v49, I am running the example in X11 from a separate terminal and there shouldn't be any app armor / sandboxing stuff interfering. I am unclear if this is related perhaps to #328 in some way?

Apologies if I am missing something obvious but I feel I am a bit stuck. I assumed that I could just do no-ops for the ActionHandler since I just want it to initialize the tree and make the announcement.

use accesskit::{
    ActionHandler, ActionRequest, ActivationHandler, DeactivationHandler, Live, Node, NodeId, Role, Tree, TreeUpdate,
};
use accesskit_unix::Adapter;

const ROOT_ID: NodeId = NodeId(0);
const ANNOUNCEMENT_ID: NodeId = NodeId(1);

struct MyActivationHandler;
struct MyActionHandler;
struct MyDeactivationHandler;

fn build_announcement(text: &str) -> Node {
    let mut node = Node::new(Role::Label);
    node.set_value(text);
    node.set_live(Live::Assertive);
    node
}

impl ActivationHandler for MyActivationHandler {
    fn request_initial_tree(&mut self) -> Option<TreeUpdate> {

        let mut root = Node::new(Role::Label);
        root.set_children(vec![ANNOUNCEMENT_ID]);

        let tree = Tree::new(ROOT_ID);
        Some(TreeUpdate {
            nodes: vec![
                (ROOT_ID, root),
                (ANNOUNCEMENT_ID, build_announcement("Hello world")),
            ],
            tree: Some(tree),
            focus: ROOT_ID,
        })
    }
}

impl ActionHandler for MyActionHandler {
    fn do_action(&mut self, request: ActionRequest) {
        println!("Action: {:?}", request);
    }
}

impl DeactivationHandler for MyDeactivationHandler {
    fn deactivate_accessibility(&mut self) {
        println!("Accessibility deactivated");
    }
}

fn main() {
    let mut adapter = Adapter::new(
        MyActivationHandler,
        MyActionHandler,
        MyDeactivationHandler,
    );

    // Send initial tree unconditionally
    adapter.update_if_active(|| MyActivationHandler.request_initial_tree().unwrap());

    println!("Adapter initialized successfully!");

    // Simulate updating the live region later
    std::thread::sleep(std::time::Duration::from_secs(2));
    adapter.update_if_active(|| TreeUpdate {
        nodes: vec![(ANNOUNCEMENT_ID, build_announcement("Hello, world again!"))],
        tree: None,
        focus: ROOT_ID,
    });

    println!("Announcement updated!");
}

[DataTriny]

Hello @C-Loftus,

You need to call Adapter::update_window_focus_state to tell AccessKit your window got the focus. In your simple program, this could be done just after the adapter is created.

However, while AT-SPI is completely decoupled from any windowing layer, I highly doubt Orca or Accerciser would notice your application if it has no real window open.

[mwcampbell]

Orca will announce your AT-SPI window's focus even if there isn't a corresponding X11 or Wayland window. But you won't be able to receive any keyboard input without a real window, only AT-SPI actions via Orca keyboard commands.

[C-Loftus]

Thank you very much both for your replies. I have followed both your advice and I now have a working example that Orca speaks using either x11 by using x11rb or headless without any window. I would be happy to contribute either. Let me know if this would be useful and I am happy to clean it up and make a PR.

I am still trying to trace why my previous example wasn't working but I think there may be some sort of initial startup race condition or latency with Orca and or atspi. Once I put the code in a loop it works great. (I also needed to add the initial focus as Arnold mentioned)

Thank you very much

[DataTriny]

An example making use of x11rb would be welcome. I had started working on it but never got to finish it.