Rather than maintain copies of the entire focus stack, this PR
transactionises the focus by introducing two new properties to the
container state and using those when rendering.
* `bool focused` means this container has actual focus. Only one
container should have this equalling true in its current state.
* `struct sway_container *focus_inactive_child` points to the immediate
child that was most recently focused (eg. for tabbed and stacked
containers).
When you have an unfocused container (so one view is focused_inactive),
and you focus any other view in that container, the view with
focused_inactive was not damaged. This is because we damaged the
previous focus and new focus, but needed to damage the parent of the new
focus.
Fixes#2192.
seat_get_active_current_child is intended to return a child of the given
container which has finished its mapping transaction and is able to be
rendered on screen. The previous implementation was capable of returning
a pending child, which caused a child of a tabbed or stacked view to be
rendered prematurely while it was mapping.
seat_get_active_child is used for tabbed and stacked containers to get
the active child. The previous implementation used seat_get_focus_inactive
then ascended the tree to the child of the tabbed/stacked container, but
this fails when the workspace itself is stacked or tabbed and the most
recently active child is floating.
The new implementation takes a more simple approach, where it directly
scans the focus stack for the first immediate child which isn't the
floating container.
Fixes#2098.
This required changing container_at_cursor to container_at_coords so
that we could get the appropriate surface (and sx/xy) without moving the
cursor.
Future work:
- Simulate a cursor for clients which have not bound to wl_touch
- Keep sending motion events when moving outside the surface (#1892)
- Bind gestures to sway commands
Replaces arrange_windows() with arrange_root(), arrange_output(),
arrange_workspace() and arrange_children_of().
Also makes fullscreen views save and restore their dimensions, which
allows it to preserve any custom resize and is also a requirement for
floating views once they are implemented.
Until now, focus changing code only considered cleaning up the last focused
workspace. This commit adds removal of empty workspace from output that just
received focus on a different workspace.
Fixes: #1797
