Design document

This is the design document for the application Epidermis.
Please note that this is a work in progress.

The mission

Epidermis aims to make changing the look of your GNOME desktop complete, rapid, simple, automatic, customisable and shareable.
As a secondary mission, Epidermis wants to aid the user in creating their own look and sharing it to other Epidermis users, but without hindering those who consume exclusively.

The look of a GNOME desktop

Ubuntu (using GNOME) has the following customisable elements, which change its look and feel:

  • Wallpaper (GNOME or compiz)
  • Metacity window border theme
  • GTK widget theme
  • Icon set
  • GNOME splash image
  • Mouse cursor theme
  • Grub bootsplash screen
  • Usplash bootsplash screen
  • GDM login screen
  • Qt theme
  • Emerald theme
  • Panel
  • Fonts
  • Sounds
  • Docks like AWN, cairo-dock...
  • Screenlets, widgets
  • Screensaver
  • Wine colours
  • Program themes:
    • Firefox
    • Opera
    • VLC
    • Java(?)

(Add anything else that you can think of here)

Epidermis' customisation unit: pigment

In order to keep Epidermis' customisations both customisable and complete, a structure involving pigments and skins was created.
A pigment is a customisation of a piece of the GNOME desktop. It contains the files necessary to activate the customisation, (with the exception of skins,) and the information describing it, including authorship, copyright, name, key words, description, main colours and a preview image.
A pigment type is a category of pigments sharing the same characteristics of the area of the GNOME desktop they affect using the same technology, for example, pigment types can include: Metacity, wallpaper, GDM login screen... Metacity and Emerald are seperate pigment types, because they use different technology.
A skin is a pigment of the type skin, it is unique in the fact that it includes links to other pigments required for the activation of the skin. It should link to (at least?) one pigment of every type (other than skin). The skin is the means through which both complete and rapid customisation occurs.

The file structure of a pigment

A pigment is one single file. It is a gzipped tar archive (.tar.gz) of other files, but it has the extension .pigment .
Its mime-type is application/x-pigment
The archive should contain:

  • A folder named data, which contains the uncompressed files necessary to activate the pigment. For example, a icon set pigment would contain the folder of the icons under data.
  • A folder named information, containing:
    • One XML file with text only information concerning the pigment
    • A preview image

(Should we allow a file to include several pigments? This would make it easier for people with no Internet access to distribute skins) (Implemented in packs)

A pigment's XML information file

Here's an example of a pigment's XML information file:

<?xml version="1.0" ?>
<name lang="en">3LCD</name>
<description lang="en">Just a different angle rendering of another wallpaper I did</description>
<author>Chris S</author>

(TODO: XML schemas)

Skin XML example

Here's an example of pigment.xml for a skin pigment.
Note that Skin is the only type of pigment that doesn't require a preview image, for the time being.

<?xml version="1.0" ?>
<name lang="en">Ubuntu Studio</name>
<description lang="en">The default Ubuntu Studio theme</description>
<copyright>Creative Commons and other</copyright>
<author>Ubuntu Studio</author>
<keyWords><keyWord lang="en">Studio</keyWord></keyWords>
<link><codename type="wallpaper">3lcd</codename></link>
<link><codename type="metacity">ubuntu-studio</codename></link>
<link><codename type="gtk">ubuntu-studio</codename></link>
<link><codename type="icons">ubuntu-studio</codename></link>
<link><codename type="gnomeSplash">blue-ubuntu</codename></link>
<link><codename type="cursors">ComixCursors-blue-regular</codename></link>
<link><codename type="grub">debian-moreblue-swirl</codename></link>
<link><codename type="gdm">blue-folder</codename></link>
<link><codename type="usplash">splash</codename></link>

The shared repository for distributing pigments

In order to simplify accessing available pigments and sharing them, using shared repositories, preferably online, is a must for Epidermis.
Epidermis currently uses a variation of Get Hot New Stuff ( Browse ( for an example of an Epidermis repository.

The user interface

The user interface has these requirements: it should include both a GUI and a command line interface, it should fit in with the customized GNOME desktop, it should keep its mission in focus and therefore hide secondary functionality. It should comply with the HIG and use GTK.

Daniel Glimm's desktop designer

Daniel Glimm has shared an independent non-functional prototype for an application very similar to Epidermis. He included screenshots, the glade file and a python app.

Here's the mock-up.
Dan's mock-upDan's mock-up

The 0.1p3 GUI

glade.zip11.29 KB

The 0.1p3 GUI was devided in two: the main app, and the creator app.
The main app
This window was devided into three: Installed, Find more and Settings.
0.1p3 screenshot 1: Installed0.1p3 screenshot 1: Installed
0.1p3 screenshot 2: Find more0.1p3 screenshot 2: Find more
0.1p3 screenshot 3: Settings0.1p3 screenshot 3: Settings
Three dialogs are displayed at the appropriate times: (progress window not displayed)
0.1p3 apply: Applying skin0.1p3 apply: Applying skin
0.1p3 customise: Customise window0.1p3 customise: Customise window
Attached is the glade file.

The creator app
This app was there for those wishing to create their own pigments without editing XML.
0.1p3 creator: Creator0.1p3 creator: Creator