Re: How to write Armenian ligatures?

From: John Hudson (john@tiro.ca)
Date: Sat Nov 24 2007 - 23:36:20 CST

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    Andrew West wrote:

    >>> I suspect that it is not Notepad per se that is doing this, but Uniscribe.
    >> Yes, it is Uniscribe, but the point is that Notepad -- unlike Word or even WordPad --
    >> exposes all the default shaping that Uniscribe provides for non-complex scripts,

    > That is quite different from what you originally said.

    Is it really? I originally wrote

            As of recent versions of Notepad, the default plain text
            editor in Windows, the same is true of the Latin script:
            OTL <rlig> and <liga> lookups are processed automatically
            (<dlig> of course, are not, because the feature is off
            by default).

    NotePad does this by making appropriate calls to Uniscribe, but I don't see this as very
    relevant to the user experience: which is that the Latin script behaves the same way as
    complex scripts in the same application. How this happens wasn't my original focus.

    >> including support for the <liga> feature.

    > Maybe not.

    I don't understand what you mean here. If I have a font that implements the <liga> feature
    and I use that font in Notepad, the <liga> feature lookups are active by default (indeed,
    there is no way to deactivate them in NotePad). I don't see any 'maybe' about it.

    ...

    > In any case I would be very suprised indeed if Notepad (or Windows
    > edit controls in general) were actually applying optional OT features
    > intelligently depending upon what was available in the selected font.

    What does 'optional' mean in this context. As I wrote, there are features that are on by
    default that (theoretically at least) can be turned off, and features that are off by
    default but that (theoretically at least) could be turned on. These kinds of features are
    both 'optional' in the sense that they are not required to be on at all times.

    > I regularly compare complex script rendering behaviour in my
    > application (BabelPad) and Notepad using the same version of
    > Uniscribe, and, on 2K and XP at least, I don't think I've ever seen
    > any different layout behaviour when Notepad has deigned to use the
    > font I have asked it use

    Right, because complex script shaping tends to involve required features and features that
    are expected to be on by default. So, for instance, the <rlig> feature is always applied
    for Arabic text and so is the <liga> feature. But for English text, you will see that
    NotePad applies the <liga> feature but Word does not. This is the sort of things to which
    I was referring. Both applications are using Uniscribe, but they are using it selectively,
    with variant results.

    John Hudson

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


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