Prepare arrange code for type safe arguments

This commit changes the arrange code in a way that will support type
safe arguments.

The arrange_output et al functions are now public, however I opted not
to use them directly yet. I've kept the generic arrange_windows there
for convenience until type safety is fully implemented. This means this
patch has much less risk of breaking things as it would otherwise.

To be type safe, arrange_children_of cannot exist in its previous form
because the thing passed to it could be either a workspace or a
container. So it's now renamed to arrange_children and accepts a list_t,
as well as the parent layout and parent's box.

There was some code which checked the grandparent's layout to see if it
was tabbed or stacked and adjusted the Y offset of the grandchild
accordingly. Accessing the grandparent layout isn't easy when using type
safe arguments, and it seemed odd to even need to do this. I determined
that this was needed because a child of a tabbed container would have a
swayc Y matching the top of the tab bar. I've changed this so a child of
a tabbed container will have a swayc Y matching the bottom of the tab
bar, which means we don't need to access the grandparent layout.  Some
tweaks to the rendering and autoconfigure code have been made to
implement this, and the container_at code appears to work without
needing any changes.

arrange_children_of (now arrange_children) would check if the parent had
gaps and would copy them to the child, effectively making the
workspace's gaps recurse into all children. We can't do this any more
without passing has_gaps, gaps_inner and gaps_outer as arguments to
arrange_children, so I've changed the add_gaps function to retrieve it
from the workspace directly.

apply_tabbed_or_stacked_layout has been split into two functions, as it
had different logic depending on the layout.

Lastly, arrange.h had an unnecessary include of transaction.h. I've
removed it, which means I've had to add it to several other files.

1 files changed, 8 insertions, 4 deletions

diff --git a/include/sway/tree/arrange.h b/include/sway/tree/arrange.h
index 346103d3..f47e8db5 100644
--- a/include/sway/tree/arrange.h
+++ b/include/sway/tree/arrange.h
@@ -1,12 +1,16 @@
 #ifndef _SWAY_ARRANGE_H
 #define _SWAY_ARRANGE_H
-#include "sway/desktop/transaction.h"
 
 struct sway_container;
 
-/**
- * Arrange layout for all the children of the given container.
- */
+void arrange_container(struct sway_container *container);
+
+void arrange_workspace(struct sway_container *workspace);
+
+void arrange_output(struct sway_container *output);
+
+void arrange_root(void);
+
 void arrange_windows(struct sway_container *container);
 
 #endif