LIGA - Supplementary Multilingual Plane

JanekZ's picture

Font has a set of glyphs in Supplementary Multilingual Plane - above BMP.
I made some ligatures and here is my headache. FontLab demo shows all ligatures, InDesign too. I'm looking for any simple application which works with this font (=supports ligatures). Very nice BabelPad shows only f_i ligature but not the rest (these important).
Any hints? The font will be used by a small community of poor people so InD is not an option.

Té Rowan's picture

Will Scribus do?

JanekZ's picture

Thanks, but unluckily not.

Té Rowan's picture

Shoulda thought of this first: How visible are the ligatures? Do they have any PUA positions that legacy apps can exploit?

JanekZ's picture

Thanks Karl, bookmarked, but nothing about ligatures.
Standard liga, no PUA.

Karl Stange's picture

Can you post an example of one of the ligatures?

JanekZ's picture

sub \u11133 \u11102 \u11100 by \u11133_u11102_u11100;


John Hudson's picture

Ooh, Chakma. How cool is that!

The problem you will run into is that Chakma, like other Abugidas, is a 'complex script' in text processing terms, so the expectation for OpenType will be that it requires layout engine assistance. What this means is that a lot of software will simply not apply OpenType Layout features to Chakma characters without the presence of such a layout engine. The behaviour you are seeing in InDesign is uncommon, in that Adobe's fallback for characters that its layout engines don't recognise as belonging to a particular supported script get generic OT feature shaping. Unfortunately, this might only help you in the short term, because if/when Adobe do get around to supporting Chakma your current implementation will likely be incompatible with (as yet unspecified) requirements for fonts to work with the layout engine.

Generally speaking, Microsoft leads the way in defining shaping engine behaviour for complex scripts and fonts. It is possible that someone at MS is working on Chakma, or that it might be bolted onto one of the existing shaping engines for related scripts. On the other hand, like other organisations, they tend to set priorities by numbers of users, so Chakma might be very low on the list of things to implement.

John Hudson's picture

By the way, I would expect ligation of signs in this way to be handled by one of the non-discretionary features, unless you want users to be able to disable the ligation. In the absence of a Chakma spec, I would use the 'ccmp' feature, but note that this is normally applied before any other shaping except language-specific variants of basic characters.

JanekZ's picture

Thank you for kind reply.
I will dig this problem in near future.

JanekZ's picture

"[Uniscribe] Version 1.626.7600.16385 that ships with Windows 7 causes any characters in the Supplementary Multilingual Plane (Plane 1) that are nor defined in Unicode 5.1 to be rendered as two square boxes" http://www.babelstone.co.uk/software/babelpad.html
That's why designer of this font can not acces his glyphs! Good news is SP1 weeds out this bug.
It could be that my problem with ligatures is caused by Uniscribe.

JanekZ's picture

Update:
Everything works beautifully in FireFox 11 and 13.

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