RE: [OpenType] Proposal: Ligatures w/ ZWJ in OpenType

Date: Thu Jul 18 2002 - 19:23:57 EDT

On 07/18/2002 12:33:21 AM Asmus Freytag wrote:

>> The German
>>support in the font could still include the rlig lookups John has
>>suggested; and an intelligent app might even activate ligatures
>>automatically (like the SHY analogy Asmus mentioned) either by setting an
>>appropriate feature over the appropriate contexts or by inserting ZWJ
>>strings at rendering time.
>German has default ligatures that are *prohbited* at certain locations,
>fine for all other instances...

>Anyway, it's the *non*-joiner, not the joiner we are talking about here.

Let's forget for a moment whether we're interested in ZWJ or ZWNJ. What do
you recommend to be the default behaviour with German text in the context
of software that has no particular knowledge of German typography and a
user that doesn't know to enter any control characters? (Let's suppose that
a font can have German-specific rules, but not the software.) Would you
rather have ligatures appear everywhere they would if English (say) had
been assumed, resulting in ligatures in inappropriate places, or would you
rather have ligatures nowhere, resulting in less elegant typography but
also no errors?

If you think the former is better (better to get elegant topography by
default even if some mistakes occur), then a font doesn't need
German-specific rules. Default rules can apply, adding standard ligatures
such as fi globally, leaving it up to the user to insert ZWNJ manually
where these ligatures would be inappropriate, or leaving it to intelligent
software to accomplish the same end by whatever means.

If you think the latter is better (better to give up elegant typography as
default behaviour to ensure no inappropriately-place liguatures), then that
could be achieved by having intelligent software inserting ZWNJ where
necessary, but in the absense of such software, the only way to ensure this
behaviour would be for fonts to have German-specific rules that do not form
the standard ligatures globally. But if that's the case, then it would
require specific action to enable the ligatures. I guess one way to
implement that is to activate a font feature that turns on (for German) the
standard ligatures globally and then leave it to the user or software to
override that using a mechanism like ZWNJ. Is that what you're looking for?

- Peter

Peter Constable

Non-Roman Script Initiative, SIL International
7500 W. Camp Wisdom Rd., Dallas, TX 75236, USA
Tel: +1 972 708 7485
E-mail: <>

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