SDL window decorations interfear with AccessKit's tree on Unix

[nvrrdt]

Fosstodon is invite only. The email on accesskit.dev isn't reachable. I tried emailing Matt through his email on his personal Github account.

Now rests contacting you through an issue here.

So, I'm trying to set up accesskit for a Vulkan c program I make on a Nixos with Cosmic, but I build and test on Ubuntu with Gnome, because Gnome should work. But it doesn't ...
Do you have any pointers to direct me in? Or do you know of troubles with the technologies I use?
I created code with the help of Claude ai and kept in mind to use Orca's focus mode, it is connected to at-spi, ...

I really want to make this work, because I'm figuring a new way of navigating a computer. You see, an html website is actually a tree of lists and I let go the design part and use the same tree for presenting elements on screen as well as steering the screenreader. I don't know if anyone already tried that before. (also I have difficulties finding fair feedback, I think that's because it's either too experimental or either too obvious as people might think nothing about the concept futurewise)

Best regards

[mwcampbell]

Hi. I did get your email. I'm sorry I didn't respond yet.

You can look at the SDL example in the accesskit-c repo to see how to use AccessKit from C in a cross-platform context.

[nvrrdt]

Hi Matt, thank you and no worries. An hour ago I saw that not the SDL example was implemented, so I changed it in the meantime. Tomorrow I install Ubuntu on my desktop and work from there in the future simplifying the feedback cycle.

[DataTriny]

Hi @nvrrdt, we are sorting out the email issue in the background.

AccessKit should run just fine on NixOS environment. We will need more details on your technical setup to figure out what is not working. You mention Vulkan, can you elaborate on how do you open the window on which you draw? Have you made sure to properly report the window focused state?

[nvrrdt]

Hi Arnold I reviewed the code I had and compared it to the hello_world.c Matt mentioned and I redid most of it so it more resembles the hello world. I do have to say I use SDL3. Testing the binary resulted in orca speaking of 'vk destroy device' and a lot more, it rambles on. Sicompass, my app, is hearable a few times, but I think in a URI (I'm not a seasoned Orca user). So there is no focus. Accerciser seems not to be working. I use ubuntu/gnome now, later I will go back to nixos/cosmic because it was overall a nicer experience except for orca. This is how the window is created: void initWindow(SiCompassApplication* app) { if (!SDL_Init(SDL_INIT_VIDEO)) { fprintf(stderr, "Failed to initialize SDL: %s\n", SDL_GetError()); exit(EXIT_FAILURE); } app->window = SDL_CreateWindow(WINDOW_TITLE, WIDTH, HEIGHT, SDL_WINDOW_VULKAN | SDL_WINDOW_RESIZABLE); if (!app->window) { fprintf(stderr, "Failed to create window: %s\n", SDL_GetError()); SDL_Quit(); exit(EXIT_FAILURE); } app->windowId = SDL_GetWindowID(app->window); app->userEvent = SDL_RegisterEvents(1); if (app->userEvent == (Uint32)-1) { fprintf(stderr, "Couldn't register user event: (%s)\n", SDL_GetError()); return; } } This is how focusing is done, SDL_Event event; while (app->running) { while (SDL_PollEvent(&event)) { switch (event.type) { case SDL_EVENT_QUIT: app->running = false; break; case SDL_EVENT_KEY_DOWN: if (event.key.windowID != app->windowId) break; handleKeys(app->appRenderer, &event); // // Enable/disable text input based on current mode // if (app->appRenderer->currentCoordinate == COORDINATE_EDITOR_INSERT || // app->appRenderer->currentCoordinate == COORDINATE_OPERATOR_INSERT || // app->appRenderer->currentCoordinate == COORDINATE_SIMPLE_SEARCH || // app->appRenderer->currentCoordinate == COORDINATE_COMMAND || // app->appRenderer->currentCoordinate == COORDINATE_EXTENDED_SEARCH) { // SDL_StartTextInput(app->window); // } else { // SDL_StopTextInput(app->window); // } break; case SDL_EVENT_TEXT_INPUT: if (event.text.windowID != app->windowId) break; if (app->appRenderer->currentCoordinate == COORDINATE_EDITOR_INSERT || app->appRenderer->currentCoordinate == COORDINATE_OPERATOR_INSERT || app->appRenderer->currentCoordinate == COORDINATE_SIMPLE_SEARCH || app->appRenderer->currentCoordinate == COORDINATE_COMMAND || app->appRenderer->currentCoordinate == COORDINATE_EXTENDED_SEARCH) { handleInput(app->appRenderer, event.text.text); } break; case SDL_EVENT_WINDOW_RESIZED: case SDL_EVENT_WINDOW_MAXIMIZED: case SDL_EVENT_WINDOW_EXPOSED: if (event.window.windowID != app->windowId) break; app->framebufferResized = true; app->appRenderer->needsRedraw = true; break; case SDL_EVENT_WINDOW_FOCUS_GAINED: if (event.window.windowID != app->windowId) break; accesskitUpdateWindowFocus(app->appRenderer, true); break; case SDL_EVENT_WINDOW_FOCUS_LOST: if (event.window.windowID != app->windowId) break; accesskitUpdateWindowFocus(app->appRenderer, false); break; default: // Handle custom accessibility events if (event.type == app->userEvent) { if (event.user.windowID != app->windowId) break; accesskit_node_id target = (accesskit_node_id)((uintptr_t)(event.user.data1 )); if (target == ELEMENT_ID) { windowStateLock(&app->appRenderer->state); if (event.user.code == SET_FOCUS_MSG) { handleKeys(app->appRenderer, &event); } windowStateUnlock(&app->appRenderer->state); } } break; } } Thanks for helping me figure this out. Op ma 2 feb 2026 om 20:19 schreef Arnold Loubriat ***@***.***

…

: *DataTriny* left a comment (AccessKit/accesskit-c#85) <#85 (comment)> Hi @nvrrdt <https://github.com/nvrrdt>, we are sorting out the email issue in the background. AccessKit should run just fine on NixOS environment. We will need more details on your technical setup to figure out what is not working. You mention Vulkan, can you elaborate on how do you open the window on which you draw? Have you made sure to properly report the window focused state? — Reply to this email directly, view it on GitHub <#85 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AHHDIG4XHQTXQAPSGRKVECT4J6PMVAVCNFSM6AAAAACTSTSF5OVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZTQMZXGE2DMNRVGU> . You are receiving this because you were mentioned.Message ID: ***@***.***>

[DataTriny]

I do have to say I use SDL3. Testing the binary resulted in orca speaking of 'vk destroy device' and a lot more, it rambles on. Sicompass, my app, is hearable a few times, but I think in a URI

Given your current setup, you might be hitting this bug: #76 where SDL delegates its window decoration handling to GTK, which takes precedence over the accessibility tree you provide. Properly fixing this will not be easy and will require cooperation between multiple projects.

I don't know which plugin libdecor would load on Cosmic, hopefully not the GTK one.

[DataTriny]

Hello @nvrrdt,

The email issue is fixed on our end.

Have you been able to gather more details on what is happening exactly with your application? See if you're not hitting the bug I describe here.

Could you please provide logs from Orca, D-Bus traffic on the private AT-SPI bus, or a video (with sound) to help us move forward? Thank you.

[nvrrdt]

Hi Arnold The orca debug is in the attachment. Accerciser gives no output. Is the behaviour of accerciser normal? Do you still need a video? For me nothing remarkable is being said. Op wo 25 feb 2026 om 21:37 schreef Arnold Loubriat ***@***.***

…

: *DataTriny* left a comment (AccessKit/accesskit-c#85) <#85 (comment)> Hello @nvrrdt <https://github.com/nvrrdt>, The email issue is fixed on our end. Have you been able to gather more details on what is happening exactly with your application? See if you're not hitting the bug I describe here <https://gitlab.freedesktop.org/libdecor/libdecor/-/issues/43>. Could you please provide logs from Orca, D-Bus traffic on the private AT-SPI bus, or a video (with sound) to help us move forward? Thank you. — Reply to this email directly, view it on GitHub <#85 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AHHDIG2OTEN5SFTQJ773UUT4NYBX7AVCNFSM6AAAAACTSTSF5OVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZTSNRRHEYDONZYGY> . You are receiving this because you were mentioned.Message ID: ***@***.***>

[nvrrdt]

Hi Arnold I did a screen capture just in case.The orca debug log is also attached. Brief explanation: every time the green field changes position, the text shown on that new position needs to be said. That's how it basically works. Navigation happens with the arrow keys. Op do 26 feb 2026 om 12:25 schreef Nico Verrijdt ***@***.***>:

…

Hi Arnold The orca debug is in the attachment. Accerciser gives no output. Is the behaviour of accerciser normal? Do you still need a video? For me nothing remarkable is being said. Op wo 25 feb 2026 om 21:37 schreef Arnold Loubriat < ***@***.***>: > *DataTriny* left a comment (AccessKit/accesskit-c#85) > <#85 (comment)> > > Hello @nvrrdt <https://github.com/nvrrdt>, > > The email issue is fixed on our end. > > Have you been able to gather more details on what is happening exactly > with your application? See if you're not hitting the bug I describe here > <https://gitlab.freedesktop.org/libdecor/libdecor/-/issues/43>. > > Could you please provide logs from Orca, D-Bus traffic on the private > AT-SPI bus, or a video (with sound) to help us move forward? Thank you. > > — > Reply to this email directly, view it on GitHub > <#85 (comment)>, > or unsubscribe > <https://github.com/notifications/unsubscribe-auth/AHHDIG2OTEN5SFTQJ773UUT4NYBX7AVCNFSM6AAAAACTSTSF5OVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZTSNRRHEYDONZYGY> > . > You are receiving this because you were mentioned.Message ID: > ***@***.***> >

[DataTriny]

Hi @nvrrdt, your last two messages don't contain any attachments. I am not sure GitHub is able to upload files you attach to your emails, you may need to use the GitHub web interface for that.

[nvrrdt]

Hi @DataTriny

Now there must be two attachments.

As lightly mentioned before: it's a keyboard driven interface, no mouse is implemented, primary navigation happens with the arrow keys. Whenever the focus is moved, the line that can be seen, should also be said by Orca.

I haven't tested it yet on Windows, nor Macos. Does it work there?

debug-2026-02-26-12_42_22.zip
https://github.com/user-attachments/assets/b35a5349-994c-42d6-abb4-dd1ceded35b5

[DataTriny]

Thanks @nvrrdt, unfortunately what I can see in the logs is that the accessibility tree Orca reads only contain a window and a few widgets representing its decorations. This tree comes from GTK, not AccessKit. This means that you are indeed hitting the libdecor issue I mentioned. There is no good fix at this time. A workaround is to run your app with the NO_AT_BRIDGE=1 environment variable set, it tells GTK to disable its accessibility hence preventing libdecor from overriding your own accessibility tree. Another option is to disable decorations when creating your SDL window, by passing the SDL_WINDOW_BORDERLESS flag. This should tell SDL to not even call libdecor. Finally you can tweak your environment to tell libdecor to use a different plugin than the GTK one, please read their documentation to find how to do that in your case.

I haven't tested it yet on Windows, nor Macos. Does it work there?

It should, at least you would not have this particular issue. Just be aware that on Windows and macOS the SDL window must first be created hidden, you can only show it after the AccessKit adapter has been installed as demonstrated in our SDL2 example.

[nvrrdt]

Thank you @DataTriny , however I don't use GTK. Any thoughts on that?
I only need a few graphical tools and I use Vulkan directly without any graphical libraries.