Developing OpenType Fonts
Features are encoded according to both a designated script and language system. There are different language systems, for example, defined for the Assamese, Bengali and Manipuri languages, although they all use the Bengali script.
Currently, the Uniscribe engine only supports the "default" language for each script. However, font developers may want to build language specific features which are supported in other applications and will be supported in future Microsoft OpenType implementations.
NOTE: It is strongly recommended to include the "dflt" language tag in all OpenType fonts, because it defines the basic script handling for a font. The "dflt" language system is used as the default if no other language specific features are defined or if the application does not support that particular language. If the "dflt" tag is not present for the script being used, the font may not work in some applications.
The following tables list the registered tag names for scripts and language systems.
The following table shows all consonant forms that Uniscribe recognizes. For example, if a consonant is marked as having a post-base form and is the last consonant in a syllable, Uniscribe will apply the "pstf" feature to it, etc.
In the table, consonants that have a reph form, below-base form and post-base form will have a check mark in those columns. All consonants are expected to have a half form, which can be a combination of the full form and a virama (halant).
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