# Supporting bidirectional text

A bidirectional language is one that can write either right to left or left to right based on context. Bidirectional text is supported throughout the platform. Eclipse will recognize Hebrew, Arabic, Farsi and Urdu as bidirectional by default.

## Enabling Bidirectional Support

The orientation of the workbench is determined in one of the following ways (in order of priority):

- -dir command line parameter. If the -dir command line option is used this will be the default orientation. Valid values are -dir rtl or -dir ltr.
- system properties. If the system property `eclipse.orientation` is set this will be used. The recognized values of this property are the same as the -dir command line argument.
- -nl command line parameter. If the -nl option is used and the language is Hebrew, Arabic, Farsi or Urdu the orientation will be right to left.
- Failing all of the above, the platform defaults to a left to right orientation.

In JFace, the orientation can be determined by calling org.eclipse.jface.Window#getDefaultOrientation(). Standalone JFace applications must set the default orientation by calling org.eclipse.jface.Window#setDefaultOrientation(), otherwise it will assume a default value of SWT.NONE. The default orientation is set automatically when running the Workbench. All subclasses of `org.eclipse.jface.Window` inherit this default orientation.

Views and editors inherit the window orientation from their parent. Dialogs should inherit orientation by using the shell style of their superclass by calling super.getShellStyle() when creating or configuring their shell.

Figure 1 - Screen shot of right to left orientation of the resource perspective in English

## Enabling Text Processing

The orientation of the workbench is independant of the special case processing for bidirectional languages. If the language of the current Locale is Hebrew, Arabic, Farsi or Urdu text processing will be enabled. Text processing is used to handle special case characters that should not be processed as birdirectional text such as path seperators. See `org.eclipse.osgi.util.TextProcessor` for more details.

## Enabling your plug-in for looking up alternate icons

In many cases your icons will not make any sense in right to left mode. In particular any icon to do with editing will have this issue.To enable lookup of images in a fragment, use $nl$ in your icon path and use the org.eclipse.core.runtime.FileLocator class to find icons at runtime.

For example

       String iconPath = "$nl$/icons/myicon.gif";
       URL url = FileLocator.find( Platform.getBundle(MyPluginId), new Path(iconPath), null);
       Image Descriptor descriptor = ImageDescriptor.createFromURL(url);

If the icon reference is in your `plugin.xml` file, make sure you have the $nl$ prefix on your path and the lookup will be handled for you. If you define your own extension points that involve icons, be sure to load images in the same way.

### How to choose icons to override

There are no hard and fast rules for determining what icons need to be overridden in a right to left language. In general, focus on icons that imply a textual direction with a horizontal arrow.