http://verahill.blogspot.com.au/2012/12/running-gimp-28-in-chroot-on-debian.html
It ain't pretty...
EDIT 27/05/2012: GIMP 2.8 is now in the debian testing repos.
GIMP 2.8 is out -- and it's got the fabled single-window mode: http://www.phoronix.com/scan.php?page=news_item&px=MTA5NjA
First you need to install babl >=0.1.10, and gegl-0.2 >= 0.2.0, then you can compile and install GIMP 2.8. The versions of babel and gegl in the debian testing/wheezy repos are too old, so you will need to compile tboth babel and gegl yourself -- luckily it is very easy to do so (see below).
Building with python script support needed a ton of packages (it requires PyGTK which depends on pygobject which depends on glib and gobject-introspection etc.), so here I passed --disable-python during build. It just means you can't script gimp with python. No python.
As always, I only spot what packages are missing on my system. If you find that other packages are missing, let me know in the comment section and I'll expand the post. At a minimum, you will need build-essential
LMDE MINT USERS: it seems like you need to add a single line to your /etc/ld.so.conf file:
/usr/local/libThen do
sudo ldconfig
ldconfig is in the package libc-bin
Both babl and gegl are gimp specific, so not giving install prefixes is probably ok. Just don't try to uninstall the pre-existing versions or gnome will disappear on you. See here http://forums.linuxmint.com/viewtopic.php?f=190&t=101253 for more LMDE discussions. See here http://cloudplasma.co.uk/2012/05/gimp-2-8-on-linux-mint-debian-edition/ for a compile based on this post.
START HERE
0. sudo apt-get install build-essential libatk1.0-dev libfontconfig1-dev libcairo2-dev libgudev-1.0-0 libdbus-1-dev libdbus-glib-1-dev liblcms1-dev libexif-dev libxfixes-dev libgtk2.0-dev python2.7-dev libtiff4-dev libpango1.0-dev
1. babl 0.1.10
wget ftp://ftp.gtk.org/pub/babl/0.1/babl-0.1.10.tar.bz2
tar xvf babl-0.1.10.tar.bz2
cd babl-0.1.10/
./configure
make
sudo make install
2. gegl 0.2.0
sudo apt-get install libglib2.0-dev zlib1g-dev
wget ftp://ftp.gtk.org/pub/gegl/0.2/gegl-0.2.0.tar.bz2
tar xvf gegl-0.2.0.tar.bz2
cd gegl-0.2.0/
./configure
make
sudo make install
3. gimp 2.8.0
sudo apt-get install intltool
wget ftp://ftp.gimp.org/pub/gimp/v2.8/gimp-2.8.0.tar.bz2
tar xvf gimp-2.8.0.tar.bz2
cd gimp-2.8.0/
./configure --prefix=/home/me/.gimp --disable-python
make
make install
3. ~/.bashrc
Chuck the following in your ~/.bashrc
alias gimp28='/home/me/.gimp/bin/gimp-2.8'
export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/usr/local/lib
and source it. (source ~/.bashrc)
Start from the terminal using
gimp28
Done!
You can turn on single-window mode, by going to Windows and checking Single-Window Mode.
Edit: posted the how-to above eight hours ago, and already linked to by Debian-facile :-)
Links to this post:
http://forums.linuxmint.com/viewtopic.php?t=101253&f=190
http://cloudplasma.co.uk/2012/05/gimp-2-8-on-linux-mint-debian-edition/
http://linuxmint-fr.org/forum/graphisme/92501-installation-de-gimp-28.html