hacking-howto: document v4 rendering
Michael Stapelberg
parent
2359c5049d
commit
5efb81250a
|
|
@ -469,54 +469,131 @@ src/layout.c, function resize_client().
|
|||
|
||||
== Rendering (src/layout.c, render_layout() and render_container())
|
||||
|
||||
*********************************************************************************
|
||||
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* :).
|
||||
*********************************************************************************
|
||||
|
||||
Rendering in i3 version 4 is the step which assigns the correct sizes for
|
||||
borders, decoration windows, child windows and the stacking order of all
|
||||
windows. In a separate step (+x_push_changes()+), these changes are pushed to
|
||||
X11.
|
||||
|
||||
Keep in mind that all these properties (+rect+, +window_rect+ and +deco_rect+)
|
||||
are temporary, meaning they will be overwritten by calling +render_con+.
|
||||
Persistent position/size information is kept in +geometry+.
|
||||
|
||||
The entry point for every rendering operation (except for the case of moving
|
||||
floating windows around) currently is +tree_render()+ which will re-render
|
||||
everything that’s necessary (for every output, only the currently displayed
|
||||
workspace is rendered). This behavior is expected to change in the future,
|
||||
since for a lot of updates, re-rendering everything is not actually necessary.
|
||||
Focus was on getting it working correct, not getting it work very fast.
|
||||
|
||||
What +tree_render()+ actually does is calling +render_con()+ on the root
|
||||
container and then pushing the changes to X11. The following sections talk
|
||||
about the different rendering steps, in the order of "top of the tree" (root
|
||||
container) to the bottom.
|
||||
|
||||
=== Rendering the root container
|
||||
|
||||
The i3 root container (+con->type == CT_ROOT+) represents the X11 root window.
|
||||
It contains one child container for every output (like LVDS1, VGA1, …), which
|
||||
is available on your computer.
|
||||
|
||||
Rendering the root will first render all tiling windows and then all floating
|
||||
windows. This is necessary because a floating window can be positioned in such
|
||||
a way that it is visible on two different outputs. Therefore, by first
|
||||
rendering all the tiling windows (of all outputs), we make sure that floating
|
||||
windows can never be obscured by tiling windows.
|
||||
|
||||
Essentially, though, this code path will just call +render_con()+ for every
|
||||
output and +x_raise_con(); render_con()+ for every floating window.
|
||||
|
||||
In the special case of having a "global fullscreen" window (fullscreen mode
|
||||
spanning all outputs), a shortcut is taken and +x_raise_con(); render_con()+ is
|
||||
only called for the global fullscreen window.
|
||||
|
||||
=== Rendering an output
|
||||
|
||||
Output containers (+con->layout == L_OUTPUT+) represent a hardware output like
|
||||
LVDS1, VGA1, etc. An output container has three children (at the moment): One
|
||||
content container (having workspaces as children) and the top/bottom dock area
|
||||
containers.
|
||||
|
||||
The rendering happens in the function +render_l_output()+ in the following
|
||||
steps:
|
||||
|
||||
1. Find the content container (+con->type == CT_CON+)
|
||||
2. Get the currently visible workspace (+con_get_fullscreen_con(content,
|
||||
CF_OUTPUT)+).
|
||||
3. If there is a fullscreened window on that workspace, directly render it and
|
||||
return, thus ignoring the dock areas.
|
||||
4. Sum up the space used by all the dock windows (they have a variable height
|
||||
only).
|
||||
5. Set the workspace rects (x/y/width/height) based on the position of the
|
||||
output (stored in +con->rect+) and the usable space
|
||||
(+con->rect.{width,height}+ without the space used for dock windows).
|
||||
6. Recursively raise and render the output’s child containers (meaning dock
|
||||
area containers and the content container).
|
||||
|
||||
=== Rendering a workspace or split container
|
||||
|
||||
From here on, there really is no difference anymore. All containers are of
|
||||
+con->type == CT_CON+ (whether workspace or split container) and some of them
|
||||
have a +con->window+, meaning they represent an actual window instead of a
|
||||
split container.
|
||||
|
||||
==== Default layout
|
||||
|
||||
In default layout, containers are placed horizontally or vertically next to
|
||||
each other (depending on the +con->orientation+). If a child is a leaf node (as
|
||||
opposed to a split container) and has border style "normal", appropriate space
|
||||
will be reserved for its window decoration.
|
||||
|
||||
==== Stacked layout
|
||||
|
||||
In stacked layout, only the focused window is actually shown (this is achieved
|
||||
by calling +x_raise_con()+ in reverse focus order at the end of +render_con()+).
|
||||
|
||||
The available space for the focused window is the size of the container minus
|
||||
the height of the window decoration for all windows inside this stacked
|
||||
container.
|
||||
|
||||
If border style is "1pixel" or "none", no window decoration height will be
|
||||
reserved (or displayed later on), unless there is more than one window inside
|
||||
the stacked container.
|
||||
|
||||
==== Tabbed layout
|
||||
|
||||
Tabbed layout works precisely like stacked layout, but the window decoration
|
||||
position/size is different: They are placed next to each other on a single line
|
||||
(fixed height).
|
||||
|
||||
==== Dock area layout
|
||||
|
||||
This is a special case. Users cannot chose the dock area layout, but it will be
|
||||
set for the dock area containers. In the dockarea layout (at the moment!),
|
||||
windows will be placed above each other.
|
||||
|
||||
=== Rendering a window
|
||||
|
||||
A window’s size and position will be determined in the following way:
|
||||
|
||||
1. Subtract the border if border style is not "none" (but "normal" or "1pixel").
|
||||
2. Subtract the X11 border, if the window has an X11 border > 0.
|
||||
3. Obey the aspect ratio of the window (think MPlayer).
|
||||
4. Obey the height- and width-increments of the window (think terminal emulator
|
||||
which can only be resized in one-line or one-character steps).
|
||||
|
||||
== Pushing updates to X11 / Drawing
|
||||
|
||||
TODO.
|
||||
|
||||
/////////////////////////////////////////////////////////////////////////////////
|
||||
|
||||
|
||||
There are several entry points to rendering: `render_layout()`,
|
||||
`render_workspace()` and `render_container()`. The former one calls
|
||||
`render_workspace()` for every screen, which in turn will call
|
||||
`render_container()` for every container inside its layout table. Therefore, if
|
||||
you need to render only a single container, for example because a window was
|
||||
removed, added or changed its title, you should directly call
|
||||
render_container().
|
||||
|
||||
Rendering consists of two steps: In the first one, in `render_workspace()`, each
|
||||
container gets its position (screen offset + offset in the table) and size
|
||||
(container's width times colspan/rowspan). Then, `render_container()` is called,
|
||||
which takes different approaches, depending on the mode the container is in:
|
||||
|
||||
=== Common parts
|
||||
|
||||
On the frame (the window which was created around the client’s window for the
|
||||
decorations), a black rectangle is drawn as a background for windows like
|
||||
MPlayer, which do not completely fit into the frame.
|
||||
|
||||
=== Default mode
|
||||
|
||||
Each clients gets the container’s width and an equal amount of height.
|
||||
|
||||
=== Stack mode
|
||||
|
||||
In stack mode, a window containing the decorations of all windows inside the
|
||||
container is placed at the top. The currently focused window is then given the
|
||||
whole remaining space.
|
||||
|
||||
=== Tabbed mode
|
||||
|
||||
Tabbed mode is like stack mode, except that the window decorations are drawn
|
||||
in one single line at the top of the container.
|
||||
|
||||
=== Window decorations
|
||||
|
||||
The window decorations consist of a rectangle in the appropriate color (depends
|
||||
|
|
@ -525,12 +602,6 @@ not focused container or not focused at all) forming the background.
|
|||
Afterwards, two lighter lines are drawn and the last step is drawing the
|
||||
window’s title (see WM_NAME) onto it.
|
||||
|
||||
=== Fullscreen windows
|
||||
|
||||
For fullscreen windows, the `rect` (x, y, width, height) is not changed to
|
||||
allow the client to easily go back to its previous position. Instead,
|
||||
fullscreen windows are skipped when rendering.
|
||||
|
||||
=== Resizing containers
|
||||
|
||||
By clicking and dragging the border of a container, you can resize the whole
|
||||
|
|
|
|||
Loading…
Reference in New Issue