Eclipse 4.2 Juno CSS

Question

I'm trying to simply update the look and feel of Eclipse Juno 4.2 via CSS stylesheets. There are a couple of tutorials I've seen, and a stackoverflow question:

• http://www.vogella.com/articles/Eclipse4CSS/article.html
• eclipse Juno custom workbench colors
• http://www.woodwardweb.com/java/eclipse_juno_th.html

I've installed the CSS spy tool, but this only lets me make temporary changes. Sigh. I've gone into the org.eclipse.platform_4.2.0.v201206081400 plugin folder, and mucked around with the plugin.xml, but none of the changes I make there have any effects (even after a restart).

How do I create a new theme and apply it WITHOUT creating, compiling and installing an entire eclipse plugin project to my local environment? Or, even better, can I just modify an existing theme?

Answer 1

Here is how I got it working.

Using a plugin

I have downloaded Eclipse UI Themes plugin as described here (direct link to an archive). But instead of extracting it into dropins directory, I extracted it into plugins. Also I changed its permissions to allow everyone to modify its files.

At this point you have:

plugins/com.github.eclipsecolortheme.themes_1.0.0.201207121019/
├── com
│   └── github
│       └── eclipsecolortheme
│           └── themes
│               └── Activator.class
├── META-INF
│   └── MANIFEST.MF
├── plugin.xml
└── themes
    └── css
        └── juno.css

juno.css file is what you want. After launching Eclipse, this theme will be available under Appearance -> Dark Juno.

Without a plugin

After looking into plugin.xml, I had an idea how to create a new theme without using any plugin.

<?xml version="1.0" encoding="UTF-8"?>
<?eclipse version="3.4"?>
<plugin>
   <extension
         point="org.eclipse.e4.ui.css.swt.theme">
      <theme
            basestylesheeturi="themes/css/juno.css"
            id="com.github.eclipsecolortheme.themes.darkjuno"
            label="Dark Juno">
      </theme>
   </extension>
</plugin>

One can add org.eclipse.e4.ui.css.swt.theme extension point to an existing plugin, say org.eclipse.platform_4.2.0.v201206081400. Moreover, its plugin.xml already have this extension point, and the only thing you have to do is to add an appropriate theme. Please note, that it must have a unique id.

      <theme
            basestylesheeturi="css/my_theme.css"
            id="org.eclipse.e4.ui.css.theme.my_theme"
            label="My Theme Name">
      </theme>

A new CSS file can be placed into the css directory, which already contains the default set of themes.

org.eclipse.platform_4.2.0.v201206081400/
├── ...
├── css
│   ├── e4_basestyle.css
│   ├── e4_classic_win7.css
│   ├── e4_classic_winxp.css
│   ├── e4_default.css
│   ├── e4_default_gtk.css
│   └── ...
├── images
│   ├── gtkGrey.png
│   ├── gtkHandleDark.png
│   ├── gtkHandle.png
│   ├── gtkTSFrameDark.png
│   ├── gtkTSFrame.png
│   └── ...
├── META-INF
│   ├── eclipse.inf
│   ├── ECLIPSE_.RSA
│   ├── ECLIPSE_.SF
│   └── MANIFEST.MF
├── platform.jar
├── plugin.properties
├── plugin.xml
└── ...

After restarting Eclipse with -clean option you will see a newly created item in the list of all themes:

UPD. 1

For my installation it seems that changes to CSS apply on Eclipse restarting (File -> Restart, or just quitting and starting it manually).

The only weird behavior I have noticed is that CSS files from ~/.e4css directory (if any exists) override thus ones from the plugin directory. I'm not sure where it comes from, but I can safely remove any files from it. I also don't know this directory even exists on non-Linux systems, but if it does, I guess it should be located somewhere in a home directory of the user, or maybe in Documents.

UPD. 2

I just tried to add a new theme from scratch and noticed that there was a small mistake in the XML above. In order to get a new theme properly registered it must have a unique id attribute. Otherwise you will get an error:

java.lang.IllegalArgumentException: A theme with the id 'org.eclipse.e4.ui.css.theme.e4_default' is already registered
    at org.eclipse.e4.ui.css.swt.internal.theme.ThemeEngine.registerTheme(ThemeEngine.java:186)
    ...

And it seems that I were not right saying just restarting Eclipse to register a new theme is enough. However, eclipse -clean does the trick.