Gloobus Preview is an quick file previewer which supports images, documents (pdf, odf, ods, etc.), source files, audio (mp3, wav, ogg and more), video (avi, ogg, mkv, flv, etc.), folders, archives, fonts, plain text files and more.
Gloobus Preview was recently fixed so it now works with Ubuntu 12.04 too. Besides the Ubuntu 12.04 fix, the latest Gloobus Preview from BZR comes with GTK3 support, support for password-protected documents, a rewritten documents plugin, WebM support, fixed ttf, pdf and video plugins and other fixes.
Here's a video I've recorded with the latest Gloobus Preview running in Ubuntu 12.04 Precise Pangolin:
(direct video link)
Install Gloobus Preview in Ubuntu
To use Gloobus Preview, you must install gloobus-sushi, a package that replaces GNOME Sushi (if installed). GNOME Sushi is an application similar to Gloobus Preview that was introduced with GNOME 3, which unfortunately doesn't integrate too well with Ubuntu.
To install the latest Gloobus Preview in Ubuntu 12.04 or 11.10 using its official PPA, use the following commands:
sudo add-apt-repository ppa:gloobus-dev/gloobus-preview sudo apt-get update sudo apt-get install gloobus-preview gloobus-sushi
The PPA also has packages for older Ubuntu versions, but you'll need to use Nautilus Elementary so the keyboard shortcut works (also, for Ubuntu older than 11.10, don't install "gloobus-sushi").
For some documents (odf, ods, etc.) to work with Gloobus Preview, you'll also have to install unoconv:
sudo apt-get install unoconv
Once installed, open Nautilus, select some file and press the SPACE key to quickly preview files using Gloobus Preview.
You can close it either by pressing the space bar again, using the close button or you can set it to quit on lose focus from its preferences. In the preferences, you can also set Gloobus Preview to always stay on top or use the GTK theme instead of its built-in theme
Using Gloobus Preview with Marlin
Marlin, the file manager that will be used by default in elementary OS, can also use Gloobus Preview. To set Marlin to use Gloobus Preview, install Dconf-Editor:
sudo apt-get install dconf-tools
Then launch Dconf-Editor, navigate to apps > marlin > preferences and set "/usr/bin/gloobus-preview" for the previewer-path. Then, just like in Nautilus, use the SPACE key to quickly preview files.
For other Linux distributions, Gloobus Preview can be downloaded via Launchpad (BZR).
Report any bugs you may find @ Launchpad.