The infrastructure to read _NET_WM_WINDOW_TYPE already exists in wlroots
(it's used for example in wlr_xwayland_or_surface_wants_focus()). But
the window type isn't easily accessible to the compositor because the
atoms to compare against are private to xwm.c.
labwc has recently gone to a fair amount of effort (including opening a
whole new xcb connection) just to get the needed window type atoms:
a04b394e59
It seems much cleaner to add the remaining few (3) atoms to wlroots and
implement a shared function which can be used by any wlroots compositor.
v2: naming updates
Previously it was supplying a pointer to private struct wlr_xwm
which was useless for compositors. The wlr_xwayland pointer in
contrast does have a generic data field and thus can be used by
compositors to attach their own pointer.
Additionally change the return value from int to bool.
This is especially useful if the compositor wants to support X11
panels to control windows. Without the signal a compositor does
have to hook into the user_event_handler callback but that would
not change the _NET_SUPPORTED root window property.
In labwc, we have had trouble with XWayland windows using the Globally
Active input model (see wlr_xwayland_icccm_input_model()). Under
traditional X11, these windows do not expect to be given focus directly
by the window manager; rather, the WM sends them a WM_TAKE_FOCUS message
prompting the client to take focus voluntarily.
Currently, these clients are difficult to support with wlroots, because
wlr_xwayland_surface_activate() assumes the client window will always
accept the keyboard focus after being sent WM_TAKE_FOCUS. Some Globally
Active client windows (e.g. panels/toolbars) don't want to be focused.
It's useless at best to focus them, and might even make them misbehave.
Others do need keyboard focus to be functional -- and there doesn't seem
to be any reliable way to know this in advance.
Adding wlr_xwayland_surface_offer_focus() allows the compositor to send
WM_TAKE_FOCUS to a client window supporting it and then see whether the
client accepts or ignores the offer. If it accepts, the surface will emit
the focus_in signal notifying the compositor that it has received focus.
This is entirely opt-in. A compositor that doesn't want to use the new
function can continue to call wlr_xwayland_surface_activate() directly
just as before.
This swaps the argument order of wlr_surface_accepts_touch() and
wlr_surface_accepts_tablet_v2(), putting the wlr_surface argument first
as should be the case for functions namespaced with wlr_surface_*.
This will let compositors know if changing adaptive_sync state has any
chance of working. When false, then the current state is the only
supported state, including if adaptive_sync is currently enabled as is
the case for Wayland and X11 backends.
When true, changing state might succeed, but no guarantee is made. It
just indicates that the backend does not already know it to be
impossible.
Since wlroots almost always significantly breaks API each minor release,
allowing parallel installation of wlroots helps packagers deal with
programs that require conflicting versions of wlroots.
Closes: #3786
This has been introduced way back in
be297d9d14 but is never used anywhere.
If compositors want to save the old dimensions before reacting to a
fullscreen or maximize event they can just grab the sizes within their
event handlers instead.
