%D \module
%D   [       file=meta-imp-gamesymbols,
%D        version=2019.10.10,
%D          title=\METAPOST\ Graphics,
%D       subtitle=Game Symbols,
%D         author=Hans Hagen,
%D           date=\currentdate,
%D      copyright={PRAGMA ADE \& \CONTEXT\ Development Team}]
%C
%C This module is part of the \CONTEXT\ macro||package and is
%C therefore copyrighted by \PRAGMA. See mreadme.pdf for
%C details.

%D The \METAFUN\ code here is not optimal and efficient but as it serves as an
%D example I decided to keep it simple. Also, performance is not really an issue
%D here anyway. Inspired by the classic \quote {Concrete Mathematics} by Don Knuth
%D we define dice and dominos, which happen to be \UNICODE\ characters now. We
%D use this opportunity to demonstrate slightly different approached.

%D Each dice gets it's own macro at the \METAPOST\ end. Watch how we use the \type
%D {simplefun} instance in combination with a calculation wrapper. This will just
%D execute the code and leave no traces in the text flow. The code itself is not
%D that spectacular:

\startMPcalculation{simplefun}

    def DiceFrame =
        pickup pencircle scaled 1/2 ;
        draw unitsquare scaled 8 ;
        pickup pencircle scaled 3/2 ;
    enddef ;

    vardef DiceOne =
        DiceFrame ;
        draw (4,4) ;
    enddef ;
    vardef DiceTwoA =
        DiceFrame ;
        draw (2,6) ; draw (6,2) ;
    enddef ;
    vardef DiceTwoB =
        DiceFrame ;
        draw (6,6) ; draw (2,2) ;
    enddef ;
    vardef DiceTwo =
        if hasoption "mpsfont" "option" "reverse" :
            DiceTwoB
        else :
            DiceTwoA
        fi ;
    enddef ;
    vardef DiceThreeA =
        DiceFrame ;
        draw (2,6) ; draw (4,4) ; draw (6,2) ;
    enddef ;
    vardef DiceThreeB =
        DiceFrame ;
        draw (6,6) ; draw (4,4) ; draw (2,2) ;
    enddef ;
    vardef DiceThree =
        if hasoption "mpsfont" "option" "reverse" :
            DiceThreeB
        else :
            DiceThreeA
        fi ;
    enddef ;
    vardef DiceFour =
        DiceFrame ;
        draw (2,6) ; draw (6,6) ; draw (2,2) ; draw (6,2) ;
    enddef ;
    vardef DiceFive =
        DiceFrame ;
        draw (2,6) ; draw (6,6) ; draw (4,4) ; draw (2,2) ; draw (6,2) ;
    enddef ;
    vardef DiceSix =
        DiceFrame ;
        draw (2,6) ; draw (6,6) ; draw (2,4) ; draw (6,4) ; draw (2,2) ; draw (6,2) ;
    enddef ;

    vardef DiceBad =
        pickup pencircle scaled 1/2 ;
        draw unitsquare scaled 8 ;
        draw (1,7) -- (7,1) ; draw (1,1) -- (7,7) ;
    enddef ;

    lmt_registerglyphs [
        name     = "dice",
        units    = 12,
        width    = 8,
        height   = 8,
        depth    = 0,
        usecolor = true,
    ] ;

    lmt_registerglyph [ category = "dice", unicode = "0x2680", code = "DiceOne;" ] ;
    lmt_registerglyph [ category = "dice", unicode = "0x2681", code = "DiceTwo;" ] ;
    lmt_registerglyph [ category = "dice", unicode = "0x2682", code = "DiceThree;" ] ;
    lmt_registerglyph [ category = "dice", unicode = "0x2683", code = "DiceFour;" ] ;
    lmt_registerglyph [ category = "dice", unicode = "0x2684", code = "DiceFive;" ] ;
    lmt_registerglyph [ category = "dice", unicode = "0x2685", code = "DiceSix;" ] ;

    lmt_registerglyph [ category = "dice", private = "invaliddice", code = "DiceBad;" ] ;

\stopMPcalculation

%D At the \TEX\ end we define three features. The reverse is just there for fun. The
%D digits features will map digits onto dice.

\definefontfeature
  [dice:normal]
  [default]
  [metapost={category=dice}]

\definefontfeature
  [dice:reverse]
  [default]
  [metapost={category=dice,option=reverse}]

\definefontfeature
  [dice:digits]
  [dice:digits=yes]

%D The mapping to dice happens here:

\startluacode

    -- local invalid = fonts.helpers.privateslot("invaliddice")

    fonts.handlers.otf.addfeature("dice:digits", {
        type      = "substitution",
        order     = { "dice:digits" },
        nocheck   = true,
        data      = {
            [0x30] = "invaliddice",
            [0x31] = 0x2680,
            [0x32] = 0x2681,
            [0x33] = 0x2682,
            [0x34] = 0x2683,
            [0x35] = 0x2684,
            [0x36] = 0x2685,
            [0x37] = "invaliddice",
            [0x38] = "invaliddice",
            [0x39] = "invaliddice",
        },
    } )

\stopluacode

%D An example is given at the the end of this file so we now move forward with
%D the dominos.

\startMPcalculation{simplefun}

    %D Because there are so many dominos we predefine the shapes and then register
    %D the lot in a loop.

    picture Dominos[] ;

    Dominos[0] := image() ;
    Dominos[1] := image(draw(4,4);) ;
    Dominos[2] := image(draw(2,6);draw(6,2););
    Dominos[3] := image(draw(2,6);draw(4,4);draw(6,2););
    Dominos[4] := image(draw(2,6);draw(6,6);draw(2,2);draw(6,2););
    Dominos[5] := image(draw(2,6);draw(6,6);draw(4,4);draw(2,2);draw(6,2););
    Dominos[6] := image(draw(2,6);draw(4,6);draw(6,6);draw(2,2);draw(4,2);draw(6,2););
  % Dominos[7] := Dominos[0] ;
  % Dominos[8] := Dominos[0] ;
  % Dominos[9] := Dominos[0] ;

    %D Defining the font properties is straightforward:

    lmt_registerglyphs [
        name     = "dominos",
        units    = 12,
        width    = 16,
        height   = 8,
        depth    = 0,
        usecolor = true,
    ] ;

    %D We have horizontal dominos:

    def DrawDominoH(expr a, b) =
        draw image (
            pickup pencircle scaled 1/2 ;
            if (getparameterdefault "mpsfont" "color" "") = "black" :
                fillup unitsquare xyscaled (16,8) ;
                draw (8,.5) -- (8,7.5) withcolor white ;
                pickup pencircle scaled 3/2 ;
                draw Dominos[a]
                    withpen currentpen
                    withcolor white ;
                draw Dominos[b] shifted (8,0)
                    withpen currentpen
                    withcolor white ;
            else :
                draw unitsquare xyscaled (16,8) ;
                draw (8,0) -- (8,8) ;
                pickup pencircle scaled 3/2 ;
                draw Dominos[a]
                    withpen currentpen ;
                draw Dominos[b] shifted (8,0)
                    withpen currentpen ;
            fi ;
        ) ;
    enddef ;

    %D and vertical ones. We could use the above macro and rotate and shift and reflect
    %D but why bother with it:

    def DrawDominoV(expr a, b) = % is H rotated and shifted
        draw image (
            pickup pencircle scaled 1/2 ;
            if (getparameterdefault "mpsfont" "color" "") = "black" :
                fillup unitsquare xyscaled (8,16) ;
                draw (.5,8) -- (7.5,8) withcolor white ;
                pickup pencircle scaled 3/2 ;
                draw Dominos[a] rotatedaround(center Dominos[a],90)
                    withpen currentpen
                    withcolor white  ;
                draw Dominos[b] rotatedaround(center Dominos[b],90) shifted (0,8)
                    withpen currentpen
                    withcolor white  ;
            else :
                draw unitsquare xyscaled (8,16) ;
                draw (0,8) -- (8,8) ;
                pickup pencircle scaled 3/2 ;
                draw Dominos[a] rotatedaround(center Dominos[a],90)
                    withpen currentpen ;
                draw Dominos[b] rotatedaround(center Dominos[b],90) shifted (0,8)
                    withpen currentpen ;
            fi ;
        ) ;
    enddef ;

    %D We have two simple loops that define the horizontal range:

    save unicode ; numeric unicode ; unicode := 127025 ; % 1F031

    for i=0 upto 6 :
        for j=0 upto 6 :
            lmt_registerglyph [
                category = "dominos",
                unicode  = unicode,
                code     = "DrawDominoH(" & decimal i & "," & decimal j & ");",
                width    = 16,
                height   = 8,
            ] ;
            unicode := unicode + 1 ;
        endfor ;
    endfor ;

    %D and the vertical range:

    save unicode ; numeric unicode ; unicode := 127075 ;

    for i=0 upto 6 :
        for j=0 upto 6 :
            lmt_registerglyph [
                category = "dominos",
                unicode  = unicode,
                code     = "DrawDominoV(" & decimal i & "," & decimal j & ");",
                width    = 8,
                height   = 16,
            ] ;
            unicode := unicode + 1 ;
        endfor ;
    endfor ;

    %D Now we're done at the \METAFUN\ end.

\stopMPcalculation

%D We predefine two features:

\definefontfeature
  [dominos:white]
  [default]
  [metapost={category=dominos}]

\definefontfeature
  [dominos:black]
  [default]
  [metapost={category=dominos,color=black}]

\definefontfeature
  [dominos:digits]
  [dominos:digits=yes]

%D This last feature is yet to be defined. We could deal with the invalid
%D dominos with some substitution trickery but let's keep it simple.

\startluacode

    local ligatures = { }
    local unicode   = 127025

    for i=0x30,0x36 do
        for j=0x30,0x36 do
            ligatures[unicode] = { i, j }
            unicode = unicode + 1 ;
        end
    end

    fonts.handlers.otf.addfeature("dominos:digits", {
        type      = "ligature",
        order     = { "dominos:digits" },
        nocheck   = true,
        data      = ligatures,
    } )

\stopluacode

\continueifinputfile{meta-imp-gamesymbols.mkxl}

\starttext

    \definefont[DominoW][Serif*dominos:white]
    \definefont[DominoB][Serif*dominos:black]
    \definefont[DominoD][Serif*dominos:white,dominos:digits]

    \startTEXpage[offset=3pt]
        \DominoW
            \char"1F043\quad 🀱\quad
            \char"1F052\quad 🀲\quad
            \char"1F038\quad 🀳\quad
            \darkgreen\char"1F049\quad \char"1F07B\quad
        \DominoB
            \char"1F087\quad
            \char"1F088\quad
            \char"1F089\quad
        \DominoD
            \darkred 12\quad56\quad64%
    \stopTEXpage

    \definefont[DiceN][Serif*dice:normal]
    \definefont[DiceR][Serif*dice:reverse]
    \definefont[DiceD][Serif*dice:normal,dice:digits]

    \startTEXpage[offset=3pt]
        \DiceN
            \dostepwiserecurse{"2680}{"2685}{1}{\char#1\quad}%
        \DiceN
            \dostepwiserecurse{"2680}{"2685}{1}{\char#1\quad}%
        \DiceD
            \darkblue 2\quad5\quad3\quad0
    \stopTEXpage

\stoptext