Re: Why people still want to encode precomposed letters

From: John Hudson (
Date: Mon Nov 24 2008 - 15:39:47 CST

  • Next message: John Hudson: "Re: Why people still want to encode precomposed letters"

    Asmus Freytag wrote:

    > I think that an algorithm could have generic tables that capture some
    > aspects of typical ink distribution for certain characters. For example,
    > the generic fact that the typical A is trigonal, whereas O or U etc.
    > typically touch the base only in the center. Having some canned
    > information like that beats having information for each individual pair.
    > If this info fails for any specific font - well, it's intended as a
    > better fallback.

    Which is why I said that the algorithmic approach won't be able to
    handle some things *reliably*. As a fallback, the algorithms may provide
    better positioning than a blind offset, but for what I consider reliable
    mark positioning design-specific anchors are necessary.

    > I also think that if such algorithms were more widely deployed, it would
    > be advantageous if there was a way for font suppliers to create and make
    > accessible generic flattened forms of diacritics. That's still cheaper
    > than designing all the specific combinations.

    Note that I, for one, am not advocating designing all the combinations
    of bases plus marks (that either might occur or might be defined as a
    desirable subset). Indeed, I wish the encoding and layout circumstances
    were such that I had to make a lot fewer precomposed diacritics than I
    am currently obliged to: if all text were NFD'd, fonts could be a heck
    of a lot smaller, requiring precomposed glyphs only for those diacritics
    whose visual form differs from appropriately positioned base+mark glyph

    If a font developer has gone to the trouble of designing flattened
    diacritics for use above capital letters, and has built precomposed
    diacritic glyphs for those that are directly encoded in Unicode, he is
    well on the way to having the shapes and data necessary to provide
    decent anchor positioning for marks.

    John Hudson

    Tiro Typeworks
    Gulf Islands, BC
    You can't build a healthy democracy with people
    who believe in little green men from Venus.
                        -- Arthur C. Clark

    This archive was generated by hypermail 2.1.5 : Mon Nov 24 2008 - 15:42:00 CST