Bug#565975: No opacity in emacs with mutter

[Thomas Renard]

Package: mutter
Version: 2.28.1~git20091208-1
Severity: normal

The opacity of the emacs23 editor does not work with mutter.

Preparation:

* Insert into .emacs for Emacs 23:

(defun djcb-opacity-modify (&optional dec)
  "modify the transparency of the emacs frame; if DEC is t,
    decrease the transparency, otherwise increase it in 10%-steps"
  (let* ((alpha-or-nil (frame-parameter nil 'alpha)) ; nil before setting
          (oldalpha (if alpha-or-nil alpha-or-nil 100))
          (newalpha (if dec (- oldalpha 5) (+ oldalpha 5))))
    (when (and (>= newalpha frame-alpha-lower-limit) (<= newalpha 100))
      (modify-frame-parameters nil (list (cons 'alpha newalpha))))))

 ;; C-8 will increase opacity (== decrease transparency)
 ;; C-9 will decrease opacity (== increase transparency
 ;; C-0 will returns the state to normal
(global-set-key (kbd "C-8") '(lambda()(interactive)(djcb-opacity-modify)))
(global-set-key (kbd "C-9") '(lambda()(interactive)(djcb-opacity-modify t)))
(global-set-key (kbd "C-0") '(lambda()(interactive)
                               (modify-frame-parameters nil `((alpha . 100)))))

* restart emacs.

How to test the problem:

Ctrl-9 should increase editor's transparency
Ctrl-8 should decrease editor's transparency
Ctrl-0 should reset transparency of the editor

Works with metacity and composite manager activated.
No transparency at all with mutter.

ii  emacs23            23.1+1-5           The GNU Emacs editor (with GTK+ user interface)
ii  emacs23-bin-common 23.1+1-5           The GNU Emacs editor's shared, architecture dependen
ii  emacs23-common     23.1+1-5           The GNU Emacs editor's shared, architecture independ



-- System Information:
Debian Release: squeeze/sid
  APT prefers testing
  APT policy: (990, 'testing'), (500, 'unstable'), (1, 'experimental')
Architecture: amd64 (x86_64)

Kernel: Linux 2.6.31-1-amd64 (SMP w/2 CPU cores)
Locale: LANG=de_DE.UTF-8, LC_CTYPE=de_DE.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash

Versions of packages mutter depends on:
ii  libatk1.0-0         1.28.0-1             The ATK accessibility toolkit
ii  libc6               2.10.2-2             GNU C Library: Shared libraries
ii  libcairo2           1.8.8-2              The Cairo 2D vector graphics libra
ii  libclutter-1.0-0    1.0.8-1              Open GL based interactive canvas l
ii  libfontconfig1      2.8.0-2              generic font configuration library
ii  libfreetype6        2.3.11-1             FreeType 2 font engine, shared lib
ii  libgconf2-4         2.28.0-1             GNOME configuration database syste
ii  libgirepository1.0- 0.6.7-2              Library for handling GObject intro
ii  libgl1-mesa-glx [li 7.6.1-1              A free implementation of the OpenG
ii  libglib2.0-0        2.22.3-1             The GLib library of C routines
ii  libgtk2.0-0         2.18.3-1             The GTK+ graphical user interface 
ii  libice6             2:1.0.6-1            X11 Inter-Client Exchange library
ii  libmutter-private0  2.28.1~git20091208-1 library for the Mutter window mana
ii  libpango1.0-0       1.26.2-1             Layout and rendering of internatio
ii  libsm6              2:1.1.1-1            X11 Session Management library
ii  libstartup-notifica 0.10-1               library for program launch feedbac
ii  libx11-6            2:1.3.2-1            X11 client-side library
ii  libxcomposite1      1:0.4.1-1            X11 Composite extension library
ii  libxcursor1         1:1.1.10-1           X cursor management library
ii  libxdamage1         1:1.1.2-1            X11 damaged region extension libra
ii  libxext6            2:1.1.1-2            X11 miscellaneous extension librar
ii  libxfixes3          1:4.0.4-1            X11 miscellaneous 'fixes' extensio
ii  libxinerama1        2:1.0.3-2            X11 Xinerama extension library
ii  libxrandr2          2:1.3.0-2            X11 RandR extension library
ii  libxrender1         1:0.9.5-1            X Rendering Extension client libra
ii  mutter-common       2.28.1~git20091208-1 shared files for the Mutter window
ii  zenity              2.28.0-1             Display graphical dialog boxes fro

Versions of packages mutter recommends:
ii  gnome-session [x-session-mana 2.28.0-4   The GNOME Session Manager
ii  xfce4-session [x-session-mana 4.6.1-1    Xfce4 Session Manager

Versions of packages mutter suggests:
ii  gnome-control-center          1:2.28.1-2 utilities to configure the GNOME d
ii  gnome-themes                  2.28.1-1   official themes for the GNOME desk
ii  xdg-user-dirs                 0.10-1     tool to manage well known user dir

-- no debconf information