%D \module
%D   [       file=meta-imp-demo,
%D        version=2021.01.21,
%D          title=\METAPOST\ Graphics,
%D       subtitle=Demo Font,
%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 This is just a demo of defining a font in \METAPOST. The rendering as well as definitions
%D are delayed till we actually need the glyph.

\startMPcalculation{simplefun}

    picture DemoSnippets[];

    vardef DemoCircle = image(fill fullcircle scaled 10 ;) enddef ;
    vardef DemoCenter = image(fill fullcircle scaled  3 ;) enddef ;

    vardef DemoLeft       = image(fill fullcircle scaled 3 shifted (-5, 0) ;) enddef ;
    vardef DemoRight      = image(fill fullcircle scaled 3 shifted ( 5, 0) ;) enddef ;
    vardef DemoUp         = image(fill fullcircle scaled 3 shifted ( 0, 5) ;) enddef ;
    vardef DemoDown       = image(fill fullcircle scaled 3 shifted ( 0,-5) ;) enddef ;
    vardef DemoLowerLeft  = image(fill fullcircle scaled 3 shifted (-5,-5) ;) enddef ;
    vardef DemoLowerRight = image(fill fullcircle scaled 3 shifted ( 5,-5) ;) enddef ;
    vardef DemoUpperRight = image(fill fullcircle scaled 3 shifted ( 5, 5) ;) enddef ;
    vardef DemoUpperLeft  = image(fill fullcircle scaled 3 shifted (-5, 5) ;) enddef ;

    vardef DemoGlyph =
        composeglyph(DemoSnippets) ;
    enddef ;

    lmt_registerglyphs [
        name     = "demo",
        units    = 10,
        width    = 10,
        height   = 10,
        depth    = 0,
    ] ;

    % we need to set up some basics (signals to the backend and such) at definition
    % time so we just force a bogus shape (zero)

    lmt_registerglyph [
        category = "demo",
    ] ;

\stopMPcalculation

\startluacode

metapost.metafonts.demo = {
    [utf.byte("g")] = {
        code   = "DemoGlyph",
        shapes = {
            { shape = "DemoCircle", color = "gray"    },
            { shape = "DemoLeft",   color = "cyan"    },
            { shape = "DemoUp",     color = "magenta" },
            { shape = "DemoCenter", color = "yellow"  },
        }
    },
    [utf.byte("h")] = {
        code   = "DemoGlyph",
        shapes = {
            { shape = "DemoCircle", color = "gray"  },
            { shape = "DemoRight",  color = "red"   },
            { shape = "DemoDown",   color = "green" },
            { shape = "DemoCenter", color = "blue"  },
        }
    },
    [19] = {
        code   = "DemoGlyph",
        shapes = {
            { shape = "DemoCircle", color = "gray"     },
            { shape = "DemoUp",     color = "darkgray" },
            { shape = "DemoDown",   color = "darkgray" },
            { shape = "DemoLeft",   color = "darkgray" },
            { shape = "DemoRight",  color = "darkgray" },
            { shape = "DemoCenter", color = "darkgray" },
        }
    },
    ["weirdsymbol"] = {
        code   = "DemoGlyph",
        shapes = {
            { shape = "DemoCircle", color = "middlegray" },
            { shape = "DemoUp",     color = "red"        },
            { shape = "DemoDown",   color = "green"      },
            { shape = "DemoLeft",   color = "blue"       },
            { shape = "DemoRight",  color = "magenta"    },
            { shape = "DemoCenter", color = "yellow"     },
        }
    },
    ["weirdersymbol"] = {
        code   = "DemoGlyph",
        shapes = {
         -- { shape = "DemoCircle",     color = "gray"        },
            { shape = "DemoCenter",     color = "darkgray"    },
            { shape = "DemoLowerLeft",  color = "red"         },
            { shape = "DemoLowerRight", color = "green"       },
            { shape = "DemoUpperRight", color = "blue"        },
            { shape = "DemoUpperLeft",  color = "yellow"      },
            { shape = "DemoUp",         color = "darkred"     },
            { shape = "DemoDown",       color = "darkgreen"   },
            { shape = "DemoLeft",       color = "darkblue"    },
            { shape = "DemoRight",      color = "darkmagenta" },
        }
    }
}

\stopluacode

\continueifinputfile{meta-imp-demo.mkxl}

\setuplayout[tight]

\setupbodyfont[dejavu]

\definefontfeature[demo][metapost=demo,metafont=demo]

\definefont[DemoA][Serif*demo]
\definefont[DemoB][Serif*demo sa .5]
\definefont[DemoC][Serif*demo sa .25]

\starttext

    \startbuffer
        x\ruledhbox{gh}%
        x\ruledhbox{\char19}%
        x\privatecharacter{weirdsymbol}%
        x\privatecharacter{weirdersymbol}%
        x%
    \stopbuffer

    \startTEXpage[offset=2pt]
        \DemoA\getbuffer\par
        \DemoB\getbuffer\quad\DemoC\getbuffer\par
    \stopTEXpage

    {\DemoA\ctxlua{fonts.helpers.setmetaglyph {
        category = "demo",
        name     = "whatever",
        code     = "DemoGlyph",
        shapes   = {
            { shape = "DemoCenter",     color = "darkgray"   },
            { shape = "DemoLowerLeft",  color = "darkred"    },
            { shape = "DemoLowerRight", color = "darkgreen"  },
            { shape = "DemoUpperRight", color = "darkblue"   },
            { shape = "DemoUpperLeft",  color = "darkyellow" },
            { shape = "DemoUp",         color = "red"        },
            { shape = "DemoDown",       color = "green"      },
            { shape = "DemoLeft",       color = "blue"       },
            { shape = "DemoRight",      color = "magenta"    },
        }
    }}}

    {\DemoA\setmetaglyph {
        category {demo}
        name     {forever}
        code     {DemoGlyph}
        shapes   {
            { shape {DemoCenter}     color {middlegray} }
            { shape {DemoLowerLeft}  color {darkgray}   }
            { shape {DemoLowerRight} color {darkgray}   }
            { shape {DemoUpperRight} color {darkgray}   }
            { shape {DemoUpperLeft}  color {darkgray}   }
            { shape {DemoUp}         color {lightgray}  }
            { shape {DemoDown}       color {lightgray}  }
            { shape {DemoLeft}       color {lightgray}  }
            { shape {DemoRight}      color {lightgray}  }
        }
    }}

    \startTEXpage[offset=2pt]
        \DemoA
        \privatecharacter{whatever}
        \privatecharacter{forever}
    \stopTEXpage

    \DemoA\setupinterlinespace \dorecurse{10}{\dorecurse{1000}{g h }\par}\page
    \DemoB\setupinterlinespace \dorecurse{20}{\dorecurse{1000}{g h }\par}\page
    \DemoC\setupinterlinespace \dorecurse{30}{\dorecurse{1000}{g h }\par}\page

    \protected\def\MyChar#1%
      {\begingroup
       \DemoA
       \iffontchar\font\privatecharactercode{forever-#1}\else
         \setmetaglyph {
           category {demo}
           name     {forever-#1}
           code     {DemoGlyph}
           shapes   {
               { shape {DemoCenter}     color {middlegray} }
               { shape {DemoLowerLeft}  color {dark#1}     }
               { shape {DemoLowerRight} color {dark#1}     }
               { shape {DemoUpperRight} color {dark#1}     }
               { shape {DemoUpperLeft}  color {dark#1}     }
               { shape {DemoUp}         color {light#1}    }
               { shape {DemoDown}       color {light#1}    }
               { shape {DemoLeft}       color {light#1}    }
               { shape {DemoRight}      color {light#1}    }
           }
         }%
       \fi
       \privatecharacter{forever-#1}%
       \endgroup}

    \dontcomplain

    \dorecurse{1000}{%
        \MyChar{red}\space
        \MyChar{green}\space
        \MyChar{blue}\space
        \MyChar{yellow}\space
    }

    \page

    \start
        \glyphxscale 1200
        \glyphyscale  800
        \dorecurse{1000}{%
            \MyChar{red}\allowbreak
            \MyChar{green}\allowbreak
            \MyChar{blue}\allowbreak
            \MyChar{yellow}\allowbreak
        }
    \stop

\stoptext