Mark Davis ☕️ <m...@macchiato.com>: > > I'm looking forward to similar postings on checkers and go pieces. (...) > And I'm looking also forward to the ♖+ZWJ+⬛️ (etc) proposal.
Well, actually ... Garth Wallace made an important observation in <http://www.unicode.org/mail-arch/unicode-ml/y2017-m04/0090.html>: >> Currently, chess fonts can be (roughly) divided into "diagram fonts" and >> "notation fonts". The major goal of Michael Everson's proposal to introduce standardized sequences with variant selectors 1 and 2 (U+FE00/1) for chess piece characters (primarily U+2654-F), as far as I understand it, is to assure "diagram" glyph design. This means fixed-width figurines centered in the character cell, with means for square color and board border elements (incl. labels), whereas "notation" style usually has proportional figurines sitting on the baseline. The square color is ignored in standard chess notation, where fields are conventionally known by their alphabetic column index ("file", A-H for a standard checkerboard) and numeric row index ("rank", 1-8), i.e. A1 through H8, which are virtually never styled as "⬛A1", "◻B1", "<background:black>B2</>" whereas figurine charactres may either augment or substitute conventional letter symbols. - Black/dark squares are those whose file and rank are either both odd or both even. - White/light squares are those whose file is odd and rank is even, or vice versa. Corollary: The glyph background is almost only important within diagram notation. Diagrams may only show select squares, so the color of the first or last one and hence intermediate ones cannot necessarily be deduced from the immediate context. (They may be implied by row and column labels, which is simple for a sighted human reader, but complex for computers and blind readers.) Although Michael Everson readily dismisses any connection to emojis, e.g. L2/16-021 or L2/16-087+088, and hence the Emoji and Emoji_Presentation character properties as well as sequences with variation selectors 15 and 16 (U+FE0E/F), normal emoji design actually matches "diagram" notation quite nicely in that all emoji glyphs are rendered within an (ideographic / em) square. Black and white squares are also already available as emojis in small U+25AA/B, medium-small U+25FE/D, medium U+25FC/B and large U+2B1B/C. The last ones would probably be preferred. Only the first ones are default text style characters. The characters for empty squares from the proposal, U+25A8/1, have no emoji representation yet. I've suggested to use the hatching characters U+25Ax for their colors as in heraldic tinctures, which relate U+25A8 to Purple ("purpure"). Without the need for ZWJ sequences, Opentype fonts can employ their Contextual Alternates `calt` feature to select the correct background color in diagram notation: In a sequence of up to eight chess pieces without an empty square with explicit color, an initial U+2656-FE0F White Rook, U+2654-FE0F White King, U+265B-FE0F Black Queen or U+265F-FE0F Black Pawn would default to a black background, U+2659-FE0F White Pawn, U+2655 White Queen, U+265A-FE0F Black King or U+265C-FE0F Black Rook to a white background. Other than that, each character uses the alternate glyph with opposing background color from its preceding (left-side) glyph. The empty squares work as explicit anchors. A font intended for print wouldn't have to use any fancy colors or effects for emoji glyphs, but only infer the centered squared presentation from a variation selector, so it could still use proportional glyph in running text. In conclusion, although I support the proposal in principle, I strongly suggest to consider to use established VS-16 and implicit contextual backgrounds instead of arbitrary VS-1 and VS-2 with explicit backgrounds. (With only VS-16, my previous remarks about the representation of empty squares would be somewhat moot. Technically, it's still redundant, but at least it would be consistent.) References -------------- - L2/16-021: http://unicode.org/L2/L2016/16021-game-pieces-emoji.pdf - L2/16-087: http://unicode.org/L2/L2016/16087-provisional-value-for-emoji.pdf - L2/16-088: http://unicode.org/L2/L2016/16088-chars-for-emoji-provisional.pdf * https://docs.google.com/spreadsheets/d/1-XLoueD__NZtOPNz4bWl_HwOmwGIt_6aEaWV-l_I0UQ/ (broken) * https://docs.google.com/spreadsheets/d/1txhi8XYKFMkCaOOFMI2z1tQkNwhzkUN-htofj-oJ1GM/ (original) * https://docs.google.com/spreadsheets/d/1KQDH9uArJr-8m4UvAEd02ixaX_-wauSwjy9qYCwIOvE/ (extended) - Hatching colors: https://github.com/Crissov/unicode-proposals/issues/222 etc.
