Work from English was possible, but from Japanese... Forget it !
The problem occurred in the Editor pane of OmegaT, not in the Matches or Glossary panes, and I suspected recent developments in the Editor to be the cause of the problem since OmegaT 1.8 did not show this issue.
After searching for information, a Java engineer at Apple who happens to monitor the Mac Java-dev list told me that the new Java 6 anti-aliasing default on OSX was probably the cause of the problem. He suggested to either add a line in the code, or to change the default value directly from the command line.
A brief exchange with the OmegaT developers concluded that the command line was the best approach especially since command line parameters could be hard coded in the Mac bundle.
The next release of OmegaT 2.0 will happen in a few days and the Mac package will include the font-smoothing parameter.
In the meanwhile, Mac users who work with the standard OmegaT package (the one that comes with the file OmegaT.jar) can start OmegaT from the command line with the following parameter:
$ java -Dapple.awt.graphics.UseQuartz="true" -jar OmegaT.jar
Users of the Mac package (the OmegaT.app file) can modify it so that it is launched with the correct parameters:
- right-click on OmegaT.app and select Show Package Contents
- find the info.plist file within the Contents folder and open it with your favorite text editor
- replace the following code:
<key>Properties</key>
<dict>
<key>apple.laf.useScreenMenuBar</key>
<string>true</string>
</dict> - with:
<key>Properties</key>
<dict>
<key>apple.laf.useScreenMenuBar</key>
<string>true</string>
<key>apple.awt.graphics.UseQuartz</key>
<string>true</string>
</dict> - save the file, close the Contents folder, and relaunch OmegaT.app
The two solutions are equivalent and should transmit the correct property to the system when you use OmegaT.
(Special thanks to Mike Swingler at Apple.)