Playing card suit symbols and colors

From: Karl Pentzlin (karl-pentzlin@acssoft.de)
Date: Sat Jan 17 2009 - 09:56:47 CST

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    Am Samstag, 17. Januar 2009 um 08:42 schrieb Asmus Freytag
    (Re: Revised Comments on some emoji symbols e-000 ... e-521,
     regarding inherent colors of emoji symbols, on the Unicode and Emoji
     lists):

    AF> ... this is like the card suits in the 26xx block. They are called
    AF> black and white, even though they are obviously intended as black and
    AF> red. You would overturn a precedent ...

    The card suit symbols, as they are encoded, are not suited as
    precedence for handling inherently or explicitly colored characters.

    If these symbols were encoded today, there probably were four symbols
    according to the four suits, simply named
    *U+xxx1 CARD SUIT SPADE
    *U+xxx2 CARD SUIT HEART
    *U+xxx3 CARD SUIT DIAMOND
    *U+xxx4 CARD SUIT CLUB
    without specific reference to colors, as spade and club are implicitly
    black, while heart and diamond are implicitly red, and there are no
    color variants which would qualify as distinct characters.

    However, the suit symbols are not encoded due to a requirement to have
    card suit symbols in Unicode. These symbols are inherited from another
    encoding industry standard, presumably the IBM code page 437 ubiquitous
    during the DOS area, which contains the four card suit symbols as filled
    variants (as color was at the time expressed by character cell
    attributes independent from the character itself).

    These characters all were "black" in the Unicode sense.

    For whatever reasons this characters were doubled at the time they
    were introduced into Unicode (version 1.1 according to the DerivedAge
    table). In the first sequence U+2660...U+2663, the "red" ones were
    included as hollow characters ("white" in Unicode terminology) while
    the "black" ones were left filled. In the second sequence
    U+2664...U+2667, the filled variants (i.e. these presumably taken from
    the original source) were added, and hollow variants were added for the
    "black" ones without apparent reason (symmetry?).

    Thus, the card suit symbols are no precedence for including any symbols
    today, except anybody would propose some symbols to include as a filled
    ("black") and additionally as a hollow ("white") variant, e.g. encoding
    emoji e+04F as two characters BLACK CHERRIES and WHITE CHERRIES.

    A valid precedence for naming colored characters is (as I wrote in my
    original mail on the Unicode and Emoji lists) U+2591...U+2593 which are
    correctly named by their shade without causing any problems.

    Thus, it will be correct to name emoji e+051 RED APPLE and e+05B GREEN
    APPLE, as these characters are symbols for red apple and green apple.

    This does not imply to introduce any new properties or encoding
    principles into Unicode.
    Any scheme to map real colors onto other terms, however, does
    introduce a new encoding principle.
    Doing such without any compelling reason and without having reached a
    broad consensus within a public discussion participated by all relevant
    bodies is strongly opposed.

    - Karl Pentzlin



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