Bug (?) in compose

[JC Ahangama]

I am commenting solely about ligatures and how fonts define them.

There are several kinds of ligatures you can define in a font. They are 
all drawn in the Private Use Area and accessed via glyph substitution 
tables. (You can make these tables using Microsoft's VOLT program). 
Lately, I see that if the character code assigned a glyph is not from 
the Unicode set, it is presumed to belong to PUA.

The substitutions for standard ligatures will happen without any 
intervention by the application you use, even inside Microsoft Notepad 
and all editors in the Mac and Linux. Unfortunately, Microsoft Word (not 
Excel) still thinks Standard ligatures are not standard but have to be 
invoked by an Open Type setting. Obviously, somebody misinterpreted the 
standard they originally wrote. Also, in the Microsoft environment, the 
default encoding for plain text is ANSI. For consistent rendering, 
anything outside American English should be encoded as UTF-8.

GERMAN:
A Fraktur font ought to work perfectly if the ligatures are invoked as 
Standard ones. There is a complication with Eszett, though. Wikipedia 
gives the orthographic rule for Eszett as the shape of ss following long 
vowels and diphthongs. So, a substitution table needs to be made to 
enforce this rule. If for some reason this combination needs to be 
overridden, then the hidden character ZWNJ can be inserted between the 
two s letters. So, the keyboard needs to have a key to type the 
Zero-width-non-joiner.

I made a font with 2500 ligatures to enforce the Sanskrit orthography 
for the Singhala script. It is actually, Romanized Singhala, much like 
Icelandic, optionally displayed using a Singhala smart font. By 2008, 
all browsers honored the formation of its Standard ligatures. Observe 
the concept here:
http://ahangama.com/edit.htm

type this: 'vaarþþa' and then add an extra 'a' at the end to see how the 
complex ligature forms.

Thanks

JC

On 10/3/2016 2:48 AM, Clock Source wrote:
> On Sat, 1 Oct 2016 11:46:59 +0300
> Ilya Anfimov <ilan at tzirechnoy.com> wrote:
>
>>   Motif  and  xforms  shows  german  ss ligature, but emits single
>> (last entered) f instead of ff ligature and single (last entered)
>> o instead of promille ligature.
> Incredible. Sounds like a bug...
>

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