Intel Moblin2's window manager, Mutter (Metacity Clutter), plugin code tracing

1. Moblin2
Window Manager(Mutter)
Plugin
William.L
wiliwe@gmail.com
2009-07-10

2. 2
• What is Mutter?
• When/Where does the window manager load plugin?
• Plugin common interfaces
• Where is the Clutter stage?
• How the window manager show Clutter stage?
• Where to add customized Clutter contents
• How the window manager choose plugins?
• Where is X-window client init script?
• How to add debug messages in codes?
Outline

3. 3
What is Mutter?
Metacity Clutter
Metacity
A lightweight window manager written by Havoc
Pennington from Red Hat
Implemented with the GTK+ 2.x toolkit
Integrates well with the GNOME 2.x platform
Clutter
An open source (LGPL 2.1) software library for creating
portable and dynamic graphical user interfaces
Uses OpenGL for rendering (optional OpenGL|ES on
mobile and embedded platforms)
Wraps an easy to use API around GL’s complexity

4. 4
When/Where does the Window Manager
load Plugin? (1/2)
Main Entry
MetacitySrc/src/core/ main.c
When it enter window manager main() and then
call meta_display_open()
Finally, meta_display_open() indirectly calls
mutter_plugin_manager_load() and loads
PluginName.so plugin
Use GModule to load plugin, PluginName.so

5. 5
When/Where does the Window Manager
load Plugin? (2/2)
Store loaded plugin contents in a object of type of
GtypeModule (MutterModule class)
Default plugin file path is store in global variable
MUTTER_PLUGIN_DIR
The path to plugin files
/usr/lib/metacity/plugins/clutter/
Current available default plugin files are
default.so
moblin-netbook.so

6. 6
Plugin common interfaces (1/2)
Defined in
MetacitySrc/src/include/ mutter-plugin.h
struct _MutterPluginClass

7. 7
Plugin common interfaces (2/2)
Interfaces
minimize()
maximize()
unmaximize()
map()
destroy()
switch_workspace()
kill_effect()
xevent_filter()
plugin_info()

8. 8
Where is the Clutter stage?
MetacitySrc/src/compositor/mutter/compositor-
mutter.c
struct _MetaCompScreen
The Clutter stage’s initialization is in
clutter_cmp_manage_screen()

9. 9
How the window manager show Clutter
stage?
Put Clutter stage on Overlay window layer that
is between Normal window and Screen Saver
window(the most top layer)
MetacitySrc/src/compositor/mutter/compositor-
mutter.c
TheXwinOfStage = clutter_x11_get_stage_window(CLUTTER_STAGE
(ClutterStage));
OverlayWin = XCompositeGetOverlayWindow (XDisplay, XRootWindow);
XreparentWindow (XDisplay, TheXwinOfStage, OverlayWin, 0, 0);

10. 10
Where to add customized Clutter contents?
In customized plugin class's constructed()
function

11. 11
How to choose plugins?
One more plugins but only one could be used in
Gconf
key - “apps/metacity/general/clutter_plugins“

12. Where is X-window client init script?
/etc/X11/moblin/xinitrc

13. How to add debug messages in codes?
Using code:
g_debug("n [%]... n", G_STRLOC, ...);