hacking-howto: talk about the tree data structure

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Michael Stapelberg 2011-11-30 20:55:48 +00:00
parent 6c112f2a9a
commit b1b139df1e
1 changed files with 12 additions and 47 deletions

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@ -63,57 +63,22 @@ to a specific file type, a window manager should not limit itself to a certain
layout (like dwm, awesome, …) but provide mechanisms for you to easily create
the layout you need at the moment.
=== The layout table
=== The layout tree
*********************************************************************************
This section has not been updated for v4.0 yet, sorry! We wanted to release on
time, but we will update this soon. Please talk to us on IRC if you need to
know stuff *NOW* :).
*********************************************************************************
/////////////////////////////////////////////////////////////////////////////////
To accomplish flexible layouts, we decided to simply use a table. The table
grows and shrinks as you need it. Each cell holds a container which then holds
windows (see picture below). You can use different layouts for each container
(default layout and stacking layout).
The data structure which i3 uses to keep track of your windows is a tree. Every
node in the tree is a container (type +Con+). Some containers represent actual
windows (every container with a +window != NULL+), some represent split
containers and a few have special purposes: they represent workspaces, outputs
(like VGA1, LVDS1, …) or the X11 root window.
So, when you open a terminal and immediately open another one, they reside in
the same container, in default layout. The layout table has exactly one column,
one row and therefore one cell. When you move one of the terminals to the
right, the table needs to grow. It will be expanded to two columns and one row.
This enables you to have different layouts for each container. The table then
looks like this:
the same split container, which uses the default layout. In case of an empty
workspace, the split container we are talking about is the workspace.
[width="15%",cols="^,^"]
|========
| T1 | T2
|========
When moving terminal 2 to the bottom, the table will be expanded again.
[width="15%",cols="^,^"]
|========
| T1 |
| | T2
|========
You can really think of the layout table like a traditional HTML table, if
youve ever designed one. Especially col- and rowspan work similarly. Below,
you see an example of colspan=2 for the first container (which has T1 as
window).
[width="15%",cols="^asciidoc"]
|========
| T1
|
[cols="^,^",frame="none"]
!========
! T2 ! T3
!========
|========
Furthermore, you can freely resize table cells.
/////////////////////////////////////////////////////////////////////////////////
To get an impression of how different layouts are represented, just play around
and look at the data structures -- they are exposed as a JSON hash. See
http://i3wm.org/docs/ipc.html#_get_tree_reply for documentation on that and an
example.
== Files