mutter-performance-source/README

Metacity is not a meta-City as in an urban center, but rather
Meta-ness as in the state of being meta. i.e. metacity : meta as
opacity : opaque. Also it may have something to do with the Meta key
on UNIX keyboards.

The first release of Metacity is version 2.3. Metacity has no need for
your petty hangups about version numbers.

COMPILING METACITY
===

You need GTK+ 1.3.x (to become 2.0). At the moment CVS HEAD is
required. Once 1.3.7 is available that will probably work. Metacity is
a fairly trivial 6000-line C program, so once you get GTK+ built it
should be no problem to build Metacity.

REPORTING BUGS AND SUBMITTING PATCHES
===

Report new bugs to hp@redhat.com for now. Will switch to Bugzilla
sometime probably.

Feel free to send patches too; Metacity is really small and simple, so
if you find a bug or want to add a feature it should be pretty easy.

See the HACKING file for some notes on hacking Metacity.

METACITY FEATURES
===

 - Boring window manager for the adult in you. Many window managers
   are like Marshmallow Froot Loops; Metacity is like Cheerios.

 - Uses GTK+ 2.0 for drawing window frames. This means colors, fonts, 
   etc. come from GTK+ theme.

 - There are 6 workspaces.

 - Global keybindings:
    Alt-F1 to Alt-F6  switch workspaces
    Alt-1  to Alt-6   switch workspaces
    Alt-Tab           forward cycle window focus
    Alt-Shift-Tab     backward cycle focus
    Alt-Escape        focus previous window
    Alt-Left Arrow    previous workspace
    Alt-Right Arrow   next workspace

 - Window keybindings:
    Alt-space         window menu

    Mnemonics work in the menu. That is, Alt-space then underlined
    letter in the menu item works.

    Choose Move from menu, and arrow keys to move the window.

    While moving, hold down Control to move slower, and 
      Shift to snap to edges.

    Choose Resize from menu, and nothing happens yet, but 
      eventually I might implement something.   

 - Window mouse bindings:

    Clicking anywhere on frame with button 1 will raise/focus window
    
    If you click a window control, such as the close button, then the 
     control will activate on button release if you are still over it
     on release (as with most GUI toolkits)

    If you click and drag borders with button 1 it resizes the window
    
    If you click and drag the titlebar with button 1 it moves the 
     window.

    If you click anywhere on the frame with button 2 it moves the window,
     without raising it.

    If you click anywhere on the frame with button 3 it shows the 
     window menu.

    If you hold down Alt and click inside a window, it will move the 
     window (buttons 1 and 2) or show menu (button 3).

    If you pick up a window with button 1 and then switch workspaces
     the window will come with you to the new workspace, this is 
     a feature copied from Enlightenment.

    If you hold down Shift while moving a window, the window snaps
     to edges of other windows and the screen.

 - Session management:

    Metacity connects to the session manager and will set itself up to
     be respawned. It theoretically restores sizes/positions/workspace
     for session-aware applications.

 - Here is an example of how you can configure the Metacity 
   window border appearance in ~/.gtkrc-2.0:

       style "metacity-style"
       {
          font_name = "Sans 16"
          MetaFrames::title_border = { 7, 7, 7, 7 }
          MetaFrames::button_width = 25
          bg[NORMAL] = { 0.0, 0.0, 0.0 }
       }

       class "MetaFrames" style "metacity-style"

   You get the idea. It is just your basic GTK+ rc file, the 
   window borders are a widget called MetaFrames, 
   look in frames.c:meta_frames_class_init() for all the style
   properties that you can configure.

   Metacity-specific styles can also be included in any GTK+ 
   theme.

 - Metacity implements much of the new window manager spec from
   freedesktop.org, and much of the ICCCM. But then there are 
   parts of each that it doesn't implement, just because I haven't
   yet.

 - Uses Pango to render text, so has cool i18n capabilities. 
   Supports UTF-8 window titles and such.

 - There are simple animations for actions such as minimization, 
   to help users see what is happening. Should probably 
   have a few more of these.

METACITY BUGS, NON-FEATURES, AND CAVEATS
===

 - Metacity creates a big file in your home directory called
   ~/metacity.log with a bunch of debug spew.

 - If you want a number of workspaces which is not 6, you have to 
   edit screen.c and recompile.

 - If you want keybindings which are not the ones mentioned above
   as features, you have to edit keybindings.c and recompile.

 - Metacity does not have any way to unminimize a window. So 
   clicking the minimize button is sort of a bad idea.
   (If you had a WM-spec-compliant tasklist, it would work
   for unminimization.)

 - Metacity uses the new window manager spec, but only random bits of
   the old GNOME spec. It correctly advertises exactly which parts of
   the GNOME spec it supports, but it does not support enough of it to
   make the GNOME task list and desk guide happy, and they do not
   support the new spec. I don't want anyone to spend time sending me
   patches to support the old GNOME spec in Metacity; instead, send
   patches to the task list and desk guide to support the new spec. As
   far as I know, Metacity does support enough of the new spec to
   allow a working tasklist and pager.

   Upshot: task list and desk guide DO NOT WORK with Metacity.

 - Metacity turns off its keybindings for Emacs, because I use 
   Alt-space in Emacs, and getting a window menu annoys me.
   This is a broken feature. My planned fix is to use super/hyper 
   instead of Alt as the main keybinding shortcut, if super/hyper 
   exist, and then keyboards with a windows key can use that for 
   WM functions and Alt for application shortcuts.
   We'd fall back to Alt if no other suitable modifier existed.
   
 - Cycling windows with Alt-Tab is flickery, AFAIK because
   Metacity passes the entire window stack to XRestackWindows() 
   every time you restack. Instead it should probably only restack 
   windows that have changed their stacking with respect to one 
   another. (But sometimes I don't see the flicker, so 
   I'm not sure.)

 - I haven't even read the ICCCM section about colormaps. So if you 
   have an 8-bit display you are basically screwed.

 - Metacity doesn't properly claim the window manager selection
   as described in the ICCCM. But then, most other window managers
   don't handle this correctly either.

 - There are probably other ICCCM-compliance issues.

 - Window placement is always cascade for now; I want to implement 
   "first fit, falling back to cascade if no fit." 
   (Configurable placement algorithms are stupid though, don't 
   send me patches for any bogus ones. Let's just pick a good one.)

 - Maximization and movement constraints do not take the 
   GNOME panel into account. Most of the code already handles
   this (using workspace->workarea in workspace.h), but 
   workspace->workarea isn't ever actually calculated.
   Metacity needs to keep this area up-to-date using the hints the
   panel sets.

 - Should support click-to-focus as an option.

 - Windows has a neat way of implementing Alt-Tab for 
   window cycling that I would like to copy. (The little 
   popup window thing.)

 - Should Metacity support flipping in right-to-left locales?
   I don't know what window managers look like in a right-to-left
   locale. I assume the window titles should be right-justified;
   should the window controls also be flipped?

 - Need keyboard shortcuts for hide/show desktop (minimize/unminimize
   all windows temporarily, basically, and focus desktop); also 
   for focusing dock windows (though since current GNOME panel has 
   no useful keynav, this doesn't get you far at the moment).

 - Resize menu item doesn't do anything. It's intended to enter
   resize-with-the-keyboard mode, similar to Move menu item.

 - I haven't set up the po subdir and translations, mostly because
   autotools seem to get all confused if you set these up but 
   don't actually have any translations. So if someone translates
   something we can set it up.

 - If you switch from sawfish to metacity without restarting X, 
   the panel often ends up buried behind the Nautilus desktop window.

   What happens is that the panel detects Sawfish has gone away, and
   turns on override redirect mode because no GNOME-aware WM is
   running (i.e. it goes into "ignore the window manager" mode). But
   the panel doesn't notice that Metacity has appeared and is
   (partially) GNOME-compliant. So Metacity doesn't see the override
   redirect panel, and leaves it behind the Nautilus desktop. I'm not
   sure whether Metacity or the panel is to blame for this.

   (To debug - use "xwininfo" on the panel, if override redirect is
    "Yes" then Metacity won't have any awareness of a window and can't
    properly stack it above the desktop. If override redirect is "No"
    then Metacity can see the panel and handle it properly. Look at
    xstuff.c:xstuff_is_compliant_wm() in the panel to get started on
    how the panel deals with this.)

 - If you have "put panel below other windows" turned on 
   in panel Global Preferences, Miscellaneous tab, you need to change  
   this to "Put panel on top of other windows." That's because
   Metacity uses semantic categories, not the legacy layer system 
   in the GNOME spec. It treats things in the legacy "dock" layer
   as semantic type dock, but if you have the panel set to be 
   in another layer, Metacity will think it's a normal window.

   You can diagnose this problem because Metacity will put panels in 
   the wrong place, and Alt+rightclick will let you perform operations
   like minimize/maximize, and Alt+leftclick will let you move the panel.
   If Metacity has detected that the panel is a panel, then none of 
   this will be enabled.

   I put a patch in the CVS version of the panel to fix this by 
   setting the new non-legacy type hint, but a panel with that 
   patch hasn't been released yet.

 - The minimize/shade animation leaves "dirt" on Metacity's own frames, 
   because Metacity handles exposes on its own frames during the 
   animation. We could fix this with a horrible GDK hack of some kind.
   I'm not sure of the best way yet.

FAQ
===

Q: Will you add my feature?

A: If it makes sense to turn on unconditionally,
   or is genuinely a harmless preference that I would not 
   be embarrassed to put in a simple, uncluttered, user-friendly
   configuration dialog.

   If the only rationale for your feature is that other window
   managers have it, or that you are personally used to it, or something
   like that, then I will not be impressed. Metacity is firmly in the
   "choose good defaults" camp rather than the "offer 6 equally broken
   ways to do it, and let the user pick one" camp.

   This is part of a "no crackrock" policy, despite some exceptions
   I'm mildly embarrassed about. For example, multiple workspaces
   probably constitute crackrock, they confuse most users
   and really are not that useful if you have a decent tasklist and 
   so on. But I am too used to them to turn them off.
   Or alternatively iconification/tasklist is crack, and workspaces/pager
   are good. But having both is certainly a bit wrong.
   Sloppy focus is probably crackrock too. Oh, and my Alt-1 thru Alt-6
   keybindings are definitely on crack.

   But don't think unlimited crack is OK just because I slipped up a
   little. No slippery slope here.   

   Don't let this discourage patches and fixes - I love those. ;-)
   Just be prepared to hear the above objections if your patch
   adds some crack-ridden configuration option.

Q: How do I add a configuration option?

A: You don't, until GConf 2 is relatively easy to compile and I feel 
   like adding it as a dependency.

Q: Will Metacity be part of GNOME?

A: This is not the current plan, though of course I'm happy to see the
   code used by anyone who's interested. Metacity may continue to suck
   forever because I might get tired of working on it; or Metacity's
   feature set might not make sense for GNOME. Who knows.

   For now Metacity is my toy hobby project that I work on when I feel
   like it.

Q: Is Metacity a Red Hat project?

A: Metacity is in no way funded, endorsed, or encouraged by Red Hat,
   Inc. - I'm guessing Red Hat would not consider "insufficient number
   of window managers for Linux" an urgent problem. Just a wild guess
   though.
 
Q: Why can't I move XMMS?

A: Because XMMS is broken and is trying to move itself. Metacity 
   does not tolerate insolent windows who believe they can
   self-manage. Use Alt-button1 to move XMMS using Metacity.

Q: Why does Metacity remember the workspace/position of some apps 
   but not others?

A: Metacity only stores sizes/positions for apps that are session 
   managed. As far as I can determine, there is no way to attempt 
   to remember workspace/position for non-session-aware apps without
   causing a lot of weird effects.

   The reason is that you don't know which non-SM-aware apps were
   launched by the session. When you initially log in, Metacity sees a
   bunch of new windows appear. But it can't distinguish between
   windows that were stored in your session, or windows you just
   launched after logging in. If Metacity tried to guess that a window
   was from the session, it could e.g. end up maximizing a dialog, or
   put a window you just launched on another desktop or in a weird
   place. And in fact I see a lot of bugs like this in window managers
   that try to handle non-session-aware apps.

   However, for session-aware apps, Metacity can tell that the
   application instance is from the session and thus restore it
   reliably, assuming the app properly restores the windows it had 
   open on session save.
   
   So the correct way to fix the situation is to make apps
   session-aware. libSM has come with X for years, it's very
   standardized, it's shared by GNOME and KDE - even twm is
   session-aware. So anyone who won't take a patch to add SM is more
   archaic than twm - and you should flame them. ;-)

   Docs on session management:
    ftp://ftp.x.org/pub/R6.4/xc/doc/hardcopy/SM/xsmp.PS.gz
    ftp://ftp.x.org:21/pub/R6.4/xc/doc/hardcopy/SM/SMlib.PS.gz

   See also the ICCCM section on SM. For GNOME apps, use the
   GnomeClient object. For a simple example of using libSM directly,
   twm/session.c in the twm source code is pretty easy to understand.

Q: How about adding viewports in addition to workspaces?

A: I could conceivably be convinced to use viewports _instead_ of
   workspaces, though currently I'm not thinking that. But I don't
   think it makes any sense to have both; it's just confusing. They
   are functionally equivalent.

Q: Did you spend a lot of time on this?

A: Metacity is about 6000 lines of code, which took a few weekends and
   evenings to write. If it ever becomes more polished it will
   probably grow 2-3 more thousand lines of code and suck a few more
   weekends of time. If I started adding all kinds of features and 
   crack-ridden configuration options, it might take more time than that. 

Q: How can you claim that you are anti-crack, while still 
   writing a window manager?

A: I have no comment on that.