Layer surfaces are not notified of cursor position changes if the surface moves, only if the cursor moves. This workaround emits a cursor position event every time a cursor ends up over a newly resized layer surface to make sure the following clicks land in the right place.
This change doesn't address sending leave events when a cursor previously present over the surface becomes away.
There are 2 separate mechanisms in play, because a layer surface gets resized in 2 steps:
1. Layer surface resize & rearrange.
2. Underlying surface resize.
The first step may affect all layer surfaces. The cursor events are sent to cursors placed over all layer surfaces which have moved (not been resized). The second step affects any layer surface whose surface changed size. The cursor event is sent only to that surface.
Together, these events cover all surfaces: those which moves, and those which changed size, as long as each layer surface resize is accompanied by an immediate surface resize.
Whenever a new surface is created, we have to update the cursor focus,
even if there's no input event. So, we generate one motion event, and
reuse the code to update the proper cursor focus. We need to do this
for all surface roles - toplevels, popups, subsurfaces.
Fixes#1162
On the X11 backend the cursor position might be outside the output
window so no output is returned leading to the assert to trigger. Use
sane fallback instead of crashing.
When e.g. running rootston under X11 it would otherwise crash when
closing rootston like:
#0 0x00007f0197da7327 in wl_list_remove () at /usr/lib/x86_64-linux-gnu/libwayland-server.so.0
#1 0x000056306fcee7fb in handle_destroy (listener=0x5630723a2948, data=0x5630723a5d20) at ../rootston/layer_shell.c:273
#2 0x00007f019800a552 in wlr_signal_emit_safe (signal=0x5630723a5e30, data=0x5630723a5d20) at ../util/signal.c:29
#3 0x00007f0197fef808 in layer_surface_destroy (surface=0x5630723a5d20) at ../types/wlr_layer_shell.c:169
#4 0x00007f0197ff0001 in client_handle_destroy (resource=0x56307229c4c0) at ../types/wlr_layer_shell.c:371
#5 0x00007f0197da2f30 in () at /usr/lib/x86_64-linux-gnu/libwayland-server.so.0
#6 0x00007f0197da77f9 in () at /usr/lib/x86_64-linux-gnu/libwayland-server.so.0
#7 0x00007f0197da301d in wl_client_destroy () at /usr/lib/x86_64-linux-gnu/libwayland-server.so.0
#8 0x00007f0197da30d8 in () at /usr/lib/x86_64-linux-gnu/libwayland-server.so.0
#9 0x00007f0197da4c12 in wl_event_loop_dispatch () at /usr/lib/x86_64-linux-gnu/libwayland-server.so.0
#10 0x00007f0197da344a in wl_display_run () at /usr/lib/x86_64-linux-gnu/libwayland-server.so.0
#11 0x000056306fcef069 in main (argc=3, argv=0x7ffd22032528) at ../rootston/main.c:83
since the output_destroy got already removed in handle_output_destroy.
