The letters usually connect on the baseline, a feature reminiscent of the Arabic script. It should be noted though, that in contrast to Arabic, joining behavior is not mandatory but rather a design choice.
DejaVu Sans has been one of the first Unicode fonts to include the N'Ko range along with the characteristic joining behavior, both added by Євгеній Мещеряков in version 2.18. To get the letters render correctly, two things are needed. First, you need to have appropriate OpenType tables, i.e. ‘init’ for initial forms, ‘medi’ for medial and ‘fina’ for terminal or final forms. Second, the rendering engine has to recognize those and apply them.
And that's where the problem starts. Windows 7 comes with a font that includes N'Ko, but its rendering engine Uniscribe does not know what to do with the N'Ko tables. As a workaround, I have added a ‘␣RQD’ (= required feature) table which specifies when to apply which of the three aforementioned tables.
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| Rendered with Firefox 4.0b3 in Windows 7 |
Unfortunately this does not work in every application in Windows, as some do not make use of all Uniscribe features or rely on alternative renderers.
Additionally this workaround seems to have no effect on XeTeX as of version 0.9997.
References:
- http://en.wikipedia.org/wiki/N%27Ko_script
- http://www.omniglot.com/writing/nko.htm
- The Unicode Standard, Version 5.2.0, chapter 13 (.pdf)
