Mousewheel Zoom is a GNOME Shell tool that enables a Compiz-like ALT + mousewheel zoom.
GNOME Shell has its own magnifier, but the zoom increases / decreases in very large steps; Mousewheel Zoom on the other hand gradually zooms in/out. And it's very easy to setup too.
(By the way, go to System Settings > Keyboard > Universal Access if you want to assign keyboard shortcuts for the built-in GNOME Shell magnifier)
Install GNOME Shell Mousewheel Zoom
Before proceeding, please note that I've tested Mousewheel Zoom and it didn't work in Ubuntu 11.10, but it worked just fine under Fedora 15.
Arch Linux users can install Mousewheel Zoom via AUR.
For Ubuntu (11.04 only for now; hopefully it will work with 11.10 soon) and Fedora 15, install python-xlib and python-dbus as well as GIT:
sudo apt-get install python-xlib python-dbus git-core
sudo yum install python-xlib dbus-python git
Then (for both Ubuntu and Fedora), run the following commands in a terminal:
cd git clone https://github.com/tobiasquinn/gnome-shell-mousewheel-zoom.git sudo mv gnome-shell-mousewheel-zoom/mousewheelzoom.py /usr/bin/ sudo chmod +x /usr/bin/mousewheelzoom.py sudo mv gnome-shell-mousewheel-zoom/mousewheelzoom.py.desktop /etc/xdg/autostart/
The last command above will set GNOME Shell Mousewheel Zoom to start automatically on login so don't run the command if you don't want that.
Now let's clean up:
rm -rf gnome-shell-mousewheel-zoom/
You can now either log out and log back in or manually run it using the following command:
Now you can use ALT + mouse scrollwheel to zoom in/out in GNOME Shell.
Thanks to rAX for the tip!