227528 2021-06-30 07:53:48 -0700 [GTK] Support a11y with GTK 4 2024-02-08 06:40:29 -0800 1 1 1 Unclassified WebKit Accessibility WebKit Nightly Build PC Linux RESOLVED FIXED InRadar P2 Normal --- 210100 1 mcatanzaro dpino alicem bugs-noreply cgarcia dpino mcatanzaro sonny webkit-bug-importer oldest_to_newest 1773740 0 mcatanzaro 2021-06-30 07:53:48 -0700 Currently GTK 4 has no support for a11y. We should start by documenting what would be required to make this work. 1773741 1 webkit-bug-importer 2021-06-30 07:53:58 -0700 <rdar://problem/79966537> 1774088 2 cgarcia 2021-07-01 06:23:16 -0700 What we currently have is a an a11y tree in the UI process built by GTK until WebKitWebView. The web view has is own accessible derived from AtkSocket. In the web process we have another a11y tree, coming from the DOM, so not associated to any GTK widget and it's built by WebKit using ATK API. The root of web process a11y tree is an AtkPlug. So, we use the ATK Socket/Plug API to connect the UI process tree with the web process one. In GTK4 most of the a11y APIs are private, internally implemented by GtkWidgets, so our WebKitWebView has a GtkAtContext by default. We need a way to override the WebKitWebView a11y implementation, or at least some of the methods. For example GetChildren returns the references to the widgets that are children of WebKitWebView, but we need to include there the root object of the DOM a11y tree. Ideally, I think it should be enough if we could override GetChildren and GetChildAtIndex methods and ChildCount property somehow. Then we would need a way to get the WebKitWebView a11y object path, so that the root of DOM a11y tree can set the Parent property accordingly. 1867302 3 mcatanzaro 2022-05-06 12:14:22 -0700 Is this fixed? 1867453 4 cgarcia 2022-05-07 01:01:20 -0700 No, we still need a way to override the WebKitWebView a11y implementation. See comment #2 1889676 5 mcatanzaro 2022-08-08 08:36:53 -0700 This depends on: https://gitlab.gnome.org/GNOME/gtk/-/issues/3597 1898533 6 mcatanzaro 2022-09-14 13:54:44 -0700 Looks like https://gitlab.gnome.org/GNOME/gtk/-/issues/5162 will provide a path forward here. 1930833 7 alicem 2023-02-03 05:43:45 -0800 https://gitlab.gnome.org/GNOME/gtk/-/merge_requests/5470 is in now, so we should be able to have it. 🎉 1930838 8 alicem 2023-02-03 05:51:10 -0800 Update: it doesn't seem to be enough for anything except entries. :( 1930841 9 alicem 2023-02-03 05:57:12 -0800 Nevermind, should be fine. 1930847 10 cgarcia 2023-02-03 06:16:27 -0800 It's not enough for our case that dom a11y tree is in a different process. See https://gitlab.gnome.org/GNOME/gtk/-/merge_requests/5032#note_1638061 2006900 11 sonny 2024-01-23 09:12:30 -0800 For information / the record GNOME Foundation via STF¹ and Igalia are funding the work to solve this and Georges at Igalia is currently working on this. ¹ https://foundation.gnome.org/2023/11/09/gnome-recognized-as-public-interest-infrastructure/ 2011023 12 feaneron 2024-02-06 09:04:43 -0800 Pull request: https://github.com/WebKit/WebKit/pull/23926 2011323 13 ews-feeder 2024-02-07 00:38:31 -0800 Committed 274201@main (da96990ed73d): <https://commits.webkit.org/274201@main> Reviewed commits have been landed. Closing PR #23926 and removing active labels. 2011382 14 dpino 2024-02-07 06:19:17 -0800 This patch broke the build for GTK-Linux-64-bit-Release-Ubuntu-LTS-Build. https://build.webkit.org/#/builders/68/builds/31562 The build error is the following: ``` /home/buildbot/worker/GTK-Linux-64-bit-Release-Ubuntu-LTS-Build/build/Source/WebKit/UIProcess/API/gtk/WebKitWebViewBase.cpp:420:10: error: invalid use of incomplete type ‘GtkAccessibleInterface’ 420 | iface->get_first_accessible_child = webkitWebViewBaseAccessibleGetFirstAccessibleChild; | ^~ In file included from /usr/include/glib-2.0/gobject/gobject.h:24, from /usr/include/glib-2.0/gobject/gbinding.h:29, from /usr/include/glib-2.0/glib-object.h:22, from /usr/include/gtk-4.0/gtk/css/gtkcssenumtypes.h:11, from /usr/include/gtk-4.0/gtk/css/gtkcss.h:34, from /usr/include/gtk-4.0/gtk/gtk.h:30, from /home/buildbot/worker/GTK-Linux-64-bit-Release-Ubuntu-LTS-Build/build/WebKitBuild/GTK/Release/WebKitGTK/DerivedSources/webkit/WebKitWebViewBase.h:35, from /home/buildbot/worker/GTK-Linux-64-bit-Release-Ubuntu-LTS-Build/build/Source/WebKit/UIProcess/API/gtk/WebKitWebViewBase.cpp:30: /usr/include/gtk-4.0/gtk/gtkaccessible.h:36:1: note: forward declaration of ‘GtkAccessibleInterface’ 36 | G_DECLARE_INTERFACE (GtkAccessible, gtk_accessible, GTK, ACCESSIBLE, GObject) | ^~~~~~~~~~~~~~~~~~~ ``` I took a look at the error and I think the problem is that `GtkAccessibleInterface` is not available in the GTK4 version used by the Ubuntu-LTS build bot (22.04): ``` $ apt-cache madison libgtk-4-dev libgtk-4-dev | 4.6.9+ds-0ubuntu0.22.04.1 | http://mirrors.kernel.org/ubuntu jammy-updates/main amd64 Packages libgtk-4-dev | 4.6.2+ds-1ubuntu2 | http://mirrors.kernel.org/ubuntu jammy/main amd64 Packages ``` **NOTE**: The Ubuntu and Debian build bots build with `--no-experimental-features` flag enabled and they do not use Flatpak SDK neither JHBuild. They build using only system libraries. GtkAccessibleInterface is available since 4.10 (https://gitlab.gnome.org/GNOME/gtk/-/blob/main/gtk/gtkaccessible.h?ref_type=heads#L56). 2011385 15 mcatanzaro 2024-02-07 06:52:27 -0800 This might work (untested, please check): diff --git a/Source/WebKit/UIProcess/API/gtk/WebKitWebViewBase.cpp b/Source/WebKit/UIProcess/API/gtk/WebKitWebViewBase.cpp index bbe3b935d788..0c1beb0a678a 100644 --- a/Source/WebKit/UIProcess/API/gtk/WebKitWebViewBase.cpp +++ b/Source/WebKit/UIProcess/API/gtk/WebKitWebViewBase.cpp @@ -304,7 +304,7 @@ struct _WebKitWebViewBasePrivate { CString tooltipText; IntRect tooltipArea; WebHitTestResultData::IsScrollbar mouseIsOverScrollbar; -#if USE(GTK4) +#if USE(GTK4) && GTK_CHECK_VERSION(4, 10, 0) #ifdef GTK_ACCESSIBILITY_ATSPI GRefPtr<GtkAccessible> socketAccessible; #endif @@ -398,7 +398,7 @@ static void webkitWebViewBaseDidExitFullScreen(WebKitWebViewBase*); static void webkitWebViewBaseRequestExitFullScreen(WebKitWebViewBase*); #endif -#if USE(GTK4) +#if USE(GTK4) && GTK_CHECK_VERSION(4, 10, 0) static GtkAccessible* webkitWebViewBaseAccessibleGetFirstAccessibleChild(GtkAccessible* accessible) { WebKitWebViewBase* webView = WEBKIT_WEB_VIEW_BASE(accessible); @@ -3475,7 +3475,7 @@ void webkitWebViewBaseCallAfterNextPresentationUpdate(WebKitWebViewBase* webView webkitWebViewBaseNextPresentationUpdateMonitorStart(webViewBase, WTFMove(callback)); } -#if USE(GTK4) +#if USE(GTK4) && GTK_CHECK_VERSION(4, 10, 0) void webkitWebViewBaseSetPlugID(WebKitWebViewBase* webViewBase, const String& plugID) { #ifdef GTK_ACCESSIBILITY_ATSPI 2011421 16 dpino 2024-02-07 09:01:18 -0800 After applying the patch I got this other error: /home/buildbot/worker/GTK-Linux-64-bit-Release-Ubuntu-LTS-Build/build/Source/WebKit/UIProcess/API/gtk/WebKitWebViewBase.cpp:312:13: error: ‘AtkObject’ was not declared in this scope; did you mean ‘GtkObject’? 312 | GRefPtr<AtkObject> accessible; | ^~~~~~~~~ | GtkObject /home/buildbot/worker/GTK-Linux-64-bit-Release-Ubuntu-LTS-Build/build/Source/WebKit/UIProcess/API/gtk/WebKitWebViewBase.cpp:312:22: error: template argument 1 is invalid 312 | GRefPtr<AtkObject> accessible; | ^ /home/buildbot/worker/GTK-Linux-64-bit-Release-Ubuntu-LTS-Build/build/Source/WebKit/UIProcess/API/gtk/WebKitWebViewBase.cpp:387:13: warning: ‘void webkitWebViewBaseAccessibleInterfaceInit(GtkAccessibleInterface*)’ declared ‘static’ but never defined [-Wunused-function] 387 | static void webkitWebViewBaseAccessibleInterfaceInit(GtkAccessibleInterface*); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ /home/buildbot/worker/GTK-Linux-64-bit-Release-Ubuntu-LTS-Build/build/Source/WebKit/UIProcess/API/gtk/WebKitWebViewBase.cpp:387:13: warning: ‘void webkitWebViewBaseAccessibleInterfaceInit(GtkAccessibleInterface*)’ used but never defined 2011481 17 dpino 2024-02-07 11:58:14 -0800 Pull request: https://github.com/webkit/webkit/pull/24020 2011721 18 feaneron 2024-02-08 06:14:40 -0800 Pull request: https://github.com/WebKit/WebKit/pull/24066 2011723 19 ews-feeder 2024-02-08 06:40:26 -0800 Committed 274284@main (4aa6d217eac5): <https://commits.webkit.org/274284@main> Reviewed commits have been landed. Closing PR #24066 and removing active labels.