Re: How to write Armenian ligatures?

From: John Hudson (
Date: Sat Nov 24 2007 - 15:25:07 CST

  • Next message: John H. Jenkins: "Re: How to write Armenian ligatures?"

    Michael S. Kaplan wrote:

    > Vista Notepad implements font instructions for non-discretionary
    > features using Uniscribe.

    The term 'discretionary' may be confusing in this context, because there are three
    possible states for an OTL feature:

    On by default; not possible to turn off (e.g. <rlig>)

    On by default; possible to turn off* (e.g. <liga>)

    Off by default; possible to turn on* (e.g. <dlig>)

    * Of course, the possibility to turn a feature on or off depends on having a UI or markup
    capable of performing these functions. In the case of Notepad, the second state -- 0n by
    default; possible to turn off -- is effectively the same as the first state, because there
    is no mechanism to turn the feature off. I believe this is the correct decision in the
    absence of such a mechanism, because if the font developer had not intended the <liga>
    feature ligatures to be on by default he would have put them in the <dlig> feature.

    Perhaps unsurprisingly, I think typeface designers are best qualified to make decisions
    about which lookups should be associated with which features and, hence, which should be
    on by default.

    If some users don't want the <liga> feature ligatures in their texts, then they should ask
    application developers to implement proper typographic control UI, so that they can turn
    these ligatures off. That is how the OpenType font architecture is designed to be used.

    John Hudson

    Tiro Typeworks
    Gulf Islands, BC
    I'm like that Umberto Eco guy, but without
    the writing.   -- anonymous caller

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