#3 FeatureParam subtable not supported

open
OpenType (9)
5
2013-12-10
2002-09-13
No

The FeatureParam subtable needs to be implemented.
AdobeJenson is the only font I'm aware of that uses this field
currently, for the "size" feature. See the Adobe feature registry.

Discussion

  • Nobody/Anonymous

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    Here's another one: Adobe Minion Pro.

     
  • Just van Rossum

    Just van Rossum - 2005-02-11

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    user_id=92689

    There are fundamental problems with this feature:
    1) Adobe got the offset to the FeatureParams block of data wrong
    2) It doesn't contain a length field, so the size if the data depends on the
    context, ie. in *which* feature it is used. Luckily, so far it's only defined
    for the 'size' feature, but what if other features start using it?

    On the OpenType list, Adobe have admitted that there is a problem, and
    that they're working on an entirely different solution.

    I have no interest in working around all this nonsense, so I'm tempted to
    close this bug as "won't fix". At least I'm going to stop feeling bad about
    not supporting FeatureParams for while, again...

     
  • George Williams

    George Williams - 2005-03-31

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    user_id=201273

    Quite a number of Adobe fonts use this feature now.
    MinionPro does too.

    Also FontForge will generate them when converting a TeX font
    into an otf format (TeX fonts also contain design size info).

    The 'size' feature has the added joy that it does not
    conform to the OpenType spec. The Feature Param offset is
    relative to the wrong thing. I'm including a email that
    appeared on the opentype mailing list about this issue:
    -----------------------------------
    Since the 'size' layout feature has come up, I should write
    something
    about its current status. A while back, we learned that the way
    'size' has been implemented in Adobe's fonts is buggy. (We
    scrambled
    absolute and relative offsets - oops!) This problem went
    unnoticed
    for so long because we don't know of any product which
    actually uses
    'size' yet. The longer I'm here, the more I appreciate the
    axiom "If
    it's not tested, it's broken." <sigh>

    Although it would be trivial to fix the code which generated
    the
    incorrect 'size' values, we've delayed, in order to consider a
    proposal that would obviate 'size' with a new table
    containing more
    information. I consider this approach much more useful, but
    haven't
    yet managed to get enough of the decision makers into the
    discussion.
    I'm sorry to say this is likely to continue moving slowly for a
    while, because the people who would implement the feature
    will be
    fully occupied with more urgent projects for several more
    months.

    For what it's worth.
    - David Lemon

     
  • Just van Rossum

    Just van Rossum - 2005-04-01

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    user_id=92689

    I don't know FontForge, but I would strongly suggest that any new
    software should NOT output the feature, especially since Adobe
    considers abandoning it altogether. I would even go so far as to say
    that the feature is evil. It must die.

     

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