Re: Windows Glyph Handling

From: Christopher Fynn (
Date: Thu Aug 25 2005 - 23:18:07 CDT

  • Next message: Philippe Verdy: "Re: Unicode TTF question"

    Philippe Verdy wrote:

    > From: "Peter Constable" <>:

    >> Philippe Verdy:

    >>> Note that a standard does not mean that it will not be proprietary as
    >>> well

    >> An ISO standard allows for proprietary IP made available under
    >> reasonable and non-discriminatory (RAND) licensing terms.

    > The important key here is "non-discriminatory". This means that the
    > inclusion of OpenType in MPEG4 must be done so that it can be licenced
    > legally for use in other systems than Microsoft Windows. It is not just
    > a question of who can licence it, but how it can be used as well. The
    > licencing terms should only allow for licencing the standard itself,
    > without necessarily have to licence other proprietary technologies (for
    > example importing Windows components, sources or technologies, onto
    > non-Windows systems).

    Does OpenType (the font file spec) need licensing? Plenty of people seem
    to make OpenType fonts, OpenType font editors, shaping engines and
    rasterizers without a license from Microsoft, Adobe - or Apple.

    As far as I can make out the only parts that may need a license relate
    to three of Apple's patents on grid fitting glyph outlines in TrueType
    fonts in order to optimize the generated bitmaps at small sizes / low
    resolution. (The same ones that were a concern in FreeType) This is
    something inherited from TrueType and would not apply to CFF OpenType

    > So it will exclude Uniscribe (due to its intricacy relations with
    > Windows GDI), but Uniscribe must implement enough interfaces to make
    > fonts effectively usable with it. This may require adding other data
    > exchanges for things that are not part of OpenType (such as the layout
    > and reordering rules), and documenting precisely the role and semantics
    > of the various OpenType feature tables to effectively support a script.
    > Without them, the fonts will have extra features needed to support a
    > script correctly, but unusable by other systems than Windows.

    IMO a list of the sub-set of non-discretionary OpenType features applied
    to each complex script, and any specific character re-ordering etc that
    needs to be done by the OT shaping engine, should be included as
    appendices to the OpenType specification itself and/or to any standards

    Otherwise there are potentially many divergent ways individual complex
    scripts could be supported using different sub sets of OT features - and
    no real standard.

    > The standard should then be enough open to allow creating and using
    > fonts for scripts still not supported by the Uniscribe layout engine,
    > and Windows itself should be able to use those extra, user-provided,
    > scripts described by OpenType fonts and layout rules.

    Thats a little difficult. You'd either have to have a system like AAT or
    Graphite where the font developer can build the shaping rules into the
    font - in which case you end up with something different from OpenType.

    Or you'd have to establish some kind of process where some kind of
    committee of people with the necessary expertise can specify the
    features for these scripts. Supposing you had such a group of people
    willing to do the work, I'm not convinced that overall this would be any
    better or faster than waiting for Microsoft to specify these things.

    > This is the area
    > where international users are complaining, as they have to wait for
    > Microsoft to have their script usable in Notepad or any application
    > whose GUI is based on visual components that are part of the Windows API
    > (notably the Windows controls), as these applications will have no
    > possibility of supporting these extra languages without having to
    > rewrite themselves the components.

    You can of course build fonts with both AAT and OpenType layout tables.
    The two font file formats are not incompatible. And there are open
    source layout engines (such as that in ICU) with at least some support
    for AAT tables. So, for a script unsupported by Uniscribe, you can build
    a font with AAT tables and state machine for the script and have
    immediate support for your script in applications which support AAT
    fonts. Later, once the OT features for that script have been specified
    by MS OpenType tables can be added.

    AAT fonts might not work in MS Notepad or MS Office - but if OpenOffice
    uses the ICU complex text layout engigne, which I think it does, it
    should be possible to get them to work in that suite of applications
    which is a pretty good start.

    - Chris

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