Set transparency of the window for a specific application

Question

Is there a way to set some transparency (it would be awesome activate this feature by shortcut-toggle) to a specific window (for example only on chromium-browser)?

Answer 1

Adding a transparent theme:

The first thing we need is to copy a GTK theme (i.e. elemantary default theme) and modify it to display transparent windows. This can be a tough task, editing and testing CSS combinations, until we find the right levels.

A more simple way to check the operation of this trick, you can install a transparent theme designed to elementary OS, executing in terminal:

sudo add-apt-repository ppa:yunnxx/elementary
sudo apt-get update
sudo apt-get install elementary-transparent-theme

Once it's installed, you can test its performance with the command:

env GTK_THEME=transparent pantheon-files

Creating a shortcut:

The easiest way to make a shortcut to launch your application with transparent theme is creating a new .desktop file.

1. Make a copy of your target application launcher. With pantheon-files, open a terminal and execute:

   sudo cp /usr/share/applications/pantheon-files.desktop /usr/share/applications/trans-pantheonfiles.desktop

2. Edit the new launcher:

   sudo scratch-text-editor /usr/share/applications/trans-pantheonfiles.desktop

3. Go to line no. 2 and change Name=Files with something like Name=TransFiles

4. Go to line no. 6 and change the Exec variable with:

   Exec=env GTK_THEME=transparent pantheon-files %U

5. Save changes.

Now you can see a new launcher in slingshot called "TransFiles". You can also add it to Plank.

The chromium problem:

Chromium browser don't follow the gtk guidelines, like others applications. To make transparent window, I suggest you to use a theme from Chrome Web Store

Sources:

Launchpad: yunn elementary

The great answer at AskUbuntu.com by Cassidy James (member of elementary team)