output: Support multiple adjacent outputs.

When querying for an adjacent output we now need an absolute position in
order to know which adjacent output that matches. (The position is
either the current mouse position or the center of the currently focused
container, depending on context.)

If two outputs have one edge each that at least partially align with
each other they now count as adjacent.

Seamless mouse is affected by this and now properly moves and positions
itself between outputs with "uneven" placement (as long as they have at
least some part of the edge adjacent to each other).

When focusing or moving a container in a specified direction the center
of the current focused container decides where to look for an adjacent
output. So if e.g. an output has two adjacent outputs to the right and a
"focus right" command is issued then it's the placement of the currently
focused container that decides which output actually gets focused.

Also, if an output has at least one output adjacent in some direction
but the entire edge is not covered (ie. it has "holes" with no outputs),
then the algorithm will choose the output that is closest to the
currently focused container (this does not apply to seamless mouse, the
pointer will just stop at the edge in that case).

1 files changed, 5 insertions, 1 deletions

diff --git a/sway/layout.c b/sway/layout.c
index fe7d820a..741addf1 100644
--- a/sway/layout.c
+++ b/sway/layout.c
@@ -533,13 +533,17 @@ swayc_t *get_swayc_in_direction_under(swayc_t *container, enum movement_directio
                         return parent;
                 }
         }
+        // If moving to an adjacent output we need a starting position (since this
+        // output might border to multiple outputs).
+        struct wlc_point abs_pos;
+        get_absolute_center_position(container, &abs_pos);
         while (true) {
                 // Test if we can even make a difference here
                 bool can_move = false;
                 int diff = 0;
                 if (parent->type == C_ROOT) {
                         sway_log(L_DEBUG, "Moving between outputs");
-                        return swayc_adjacent_output(container, dir);
+                        return swayc_adjacent_output(container, dir, &abs_pos, true);
                 } else {
                         if (dir == MOVE_LEFT || dir == MOVE_RIGHT) {
                                 if (parent->layout == L_HORIZ) {