This patch aims to correctly handle moving focus <left|right|up|down>
between outputs.
For instance, if moving from one output to a new output at the left of
the current one, it should focus the right-most view/container on the
new output, and the opposite if moving from right to left. This should
happen regardless of the previously stored focus of the new output.
This also handles moving to a new output above or below the current one.
If the width or height of a container can't be evenly distributed to its
children, then the layout algorithm still thought it got it right (due
to using decimals) which caused a gap of one or more pixels for some
window arrangements.
This is fixed by this patch by first rounding off the width and height
(so that decimals are never introduced) and then adjusting the last
view in a container to fill the remaining pixels (which now is counted
correctly due to the decimals being removed).
Also, due to the way gaps are implemented, an odd sized gap can never be
aligned properly, so just adjust to closest even number.
Track each panel separately via its wl_resource. `set_panel_position`
might be called before `set_panel`, so reuse panel config.
Place the position in panel_config so that each panel has its own
position.
If the output is not at the correct size then that info must be queried
from wlc. The output size is used by e.g. seamless mouse to detect
output edges.
With this patch the output size is now correct and the workspace size is
adjusted according to any panels.
Without this patch seamless mouse would fail to detect outputs
above/below each other if there was a panel in between because the
output would offically end where the panel started, not at the actual
screen edge.
If focus would move in an output with a fullscreen view, it always
leaves the output. If focus would enter an output with a fullscreen
view, it always focuses the fullscreened view.
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).
When yes, the old behaviour of adding half the inner gap around each
view is used.
When no, don't add any gap when an edge of the view aligns with the
workspace. The result is inner gap only between views, not against the
workspace edge.
The algorithm is not perfect because it means the extra space is
distributed amongst edge-aligned views only, but it's simple, looks good
and it works.
