[Silgraphite-devel] ScriptTag issues

[Martin H. <mar...@si...>]

Dear All,

In a bid to start clearing up the remaining bugs, etc. Time to look at ScriptTag.

It's odd that this is a global since it is designed for bringing together separate descriptions for different scripts into one font and allowing an engine to specify a script that they want rendering, much like OpenType.

Currently, if you set a ScriptTag, then xetex fails to run the graphite rules (perhaps they would work if we specified the script in the font instantiation, but probably not). And there is no way to bring descriptions for multiple scripts together.

I realise that the former problem is fixed in more recent engine code (or that graphite utilities has no such problems) and also that nobody has actually asked for the latter.

But since we are in a tidying up mode, perhaps we can sort this one out?

Do we also need to start writing a more sophisticated string segmenter based on what characters are supported by a script. Does this mean we need some kind of coverage table of all the glyphs that a particular GDL description interacts with?

Just some random thoughts.

GB,
Martin