% language=uk

\definecolor[red]    [r=.6]
\definecolor[green]  [g=.6]
\definecolor[blue]   [b=.6]

\definecolor[cyan]   [g=.6,b=.6]
\definecolor[magenta][r=.6,b=.6]
\definecolor[yellow] [r=.6,g=.6]

\usemodule[abbreviations-smallcaps]
\usemodule[scite]
\usemodule[scite]

\setuptyping[option=TEX]
\setuptype[option=TEX]

\dontcomplain

\usebodyfont [modern]
\usebodyfont[pagella]
\usebodyfont [dejavu]

\setuppapersize[S6]

\definebodyfontenvironment[24pt]

\definecolor[maincolor][r=.6]
\definecolor[maintrans][r=.6,t=.5,a=1]
\definecolor[moretrans][g=.6,t=.5,a=1]

\setuplayout
  [width=middle,
   height=middle,
   margin=0cm,
   header=0cm,
   footer=0cm,
   topspace=1cm,
   bottomspace=1cm,
   backspace=1cm]

\setupbackgrounds
  [page]
  [background=color,
   backgroundcolor=darkgray]

\setupbackgrounds
  [text][text]
  [background=color,
   backgroundoffset=5mm,
   backgroundcolor=middlegray]

\definefontfeature[bbox][boundingbox=frame]

\definefont
  [LargeFont]
  [SansBold*default,boldened-20,bbox @ 40pt]

\definefont
  [SmallFont]
  [SansBold*default,boldened-20 @ 20pt]

\definefont
  [HeadFont]
  [SansBold*default,boldened-30 @ 30pt]

\setupbodyfont
  [modernlatin,14.4pt]

\setuphead
  [title]
  [style=\HeadFont,
   color=maincolor,
   align=middle]

\definefontsynonym[BenchMark][lmroman10regular]

\starttext

\startstandardmakeup[footerstate=start]
    \LargeFont \maincolor \setupalign[middle]
    \vfil
    \dontleavehmode\scale[width=.6\textwidth]{\setstrut\strut Modern}
    \vfil
    \dontleavehmode\scale[width=.8\textwidth]{\setstrut\strut Latin}
    \vfil
    \vfil
    \SmallFont \darkgray Bacho\TeX\ 2018\enspace\emdash\enspace Hans Hagen
\stopstandardmakeup

\starttitle[title=Why oh why]

\startitemize
\startitem
    In \CONTEXT\ we have a mechanism to apply effects to a glyph stream.
\stopitem
\startitem
    An active user on the \CONTEXT\ mailing list wondered if that could be
    applied to specific fonts.
\stopitem
\startitem
    The particular interest concerned the possibility to bolden fonts.
\stopitem
\startitem
    I don't really like effects and not all fonts are suitable for it.
\stopitem
\stopitemize

\stoptitle

\starttitle[title=What are effects]

Normal effects are implemented using the \quote {effects} mechanism, which
already dates way back in \MKII\ times and of course is also available for
\MKIV.

\defineeffect [inner]   [alternative=inner,rulethickness=1.25pt]
\defineeffect [outer]   [alternative=outer,rulethickness=1.25pt]
\defineeffect [both]    [alternative=both, rulethickness=1.25pt]
\defineeffect [normal]  [alternative=normal]

\starttyping
\defineeffect
  [outer]
  [alternative=outer,
   rulethickness=1.25pt]

effect \starteffect[outer]effect\stopeffect
\stoptyping

\startlinecorrection

    \definefont[DemoFont][BenchMark*default @ 70pt]

    \scale[width=\textwidth]{\startcombination[3*2]
      {\DemoFont\setstrut\strut\starteffect               [inner]effect\stopeffect}
      {\startoverlay
          {\DemoFont\setstrut\strut\maintrans \starteffect[inner]effect\stopeffect}
          {\DemoFont\setstrut\strut\moretrans                    effect}
       \stopoverlay}
      {\DemoFont\setstrut\strut\starteffect               [outer]effect\stopeffect}
      {\startoverlay
          {\DemoFont\setstrut\strut\maintrans \starteffect[outer]effect\stopeffect}
          {\DemoFont\setstrut\strut\moretrans                    effect}
       \stopoverlay}
      {\DemoFont\setstrut\strut\starteffect                [both]effect\stopeffect}
      {\startoverlay
          {\DemoFont\setstrut\strut\maintrans \starteffect [both]effect\stopeffect}
          {\DemoFont\setstrut\strut\moretrans                    effect}
       \stopoverlay}
      {\startoverlay
          {\DemoFont\setstrut\strut\moretrans                    effect}
          {\DemoFont\setstrut\strut\maintrans \starteffect[inner]effect\stopeffect}
       \stopoverlay}
      {\tttf inner}
      {\startoverlay
          {\DemoFont\setstrut\strut\moretrans                    effect}
          {\DemoFont\setstrut\strut\maintrans \starteffect[outer]effect\stopeffect}
       \stopoverlay}
      {\tttf outer}
      {\startoverlay
          {\DemoFont\setstrut\strut\moretrans                    effect}
          {\DemoFont\setstrut\strut\maintrans \starteffect [both]effect\stopeffect}
       \stopoverlay}
      {\tttf both}
    \stopcombination}

\stoplinecorrection

\stoptitle

\starttitle[title=How tricky is this]

\startitemize
\startitem
    Of course the only way to deal with this nicely is by using runtime created
    virtual fonts.
\stopitem
\startitem
    So called \PDF\ literals can interfere badly with font switches at the \PDF\
    level and are therefore very inefficient.
\stopitem
\startitem
    In order to properly support effects at the font level, we need to be able to
    inject the right \PDF\ code in a more clever way.
\stopitem
\startitem
    Two new keys were added to the font file definition table: \type{width} and
    \type {mode}. When set these inject a \PDF\ line width operation and trigger the
    right rendering mode (backend).
\stopitem
\stopitemize

\stoptitle

\starttitle[title=What interface do we need]

\startbuffer
\definefontfeature[effect-1][effect={width=0.8}]
\definefontfeature[bbox]    [boundingbox=frame]

\definefont
  [EffectiveFont]
  [BenchMark*default,effect-1,bbox @ 12pt]
\stopbuffer

\typebuffer \getbuffer

\startlinecorrection[2*big]
\scale[width=\textwidth]{\backgroundline[maincolor]{\EffectiveFont effective}}
\stoplinecorrection

\page

\startbuffer
\definefontfeature[effect-2][effect={width=1.1,wdelta=1.20}]
\definefontfeature[effect-3][effect={width=1.1,wdelta=1.80}]

\definefont
  [EffectiveFontA]
  [BenchMark*default,effect-2 @ 12pt]

\definefont
  [EffectiveFontB]
  [BenchMark*default,effect-3 @ 12pt]
\stopbuffer

\typebuffer \getbuffer

\scale[width=\textwidth]{\darkgray\showglyphs \EffectiveFontA effect \EffectiveFontB effect}

\stoptitle

\starttitle[title=Can we do better]

\startitemize
\startitem
    This is still not good enough so next came playing with extended shapes. This is an
    old feature inherited from \POSTSCRIPT\ times and \PDFTEX.
\stopitem
\startitem
    The \LUATEX\ backend is very efficient with this kind of trickery and combines
    it with font scaling.
\stopitem
\startitem
    It was trivial to add a similar scaling in the vertical direction.
\stopitem
\stopitemize

\page

\startbuffer
\definefontfeature[effect-4]
  [effect={width=0.5,wdelta=1.5}]

\definefontfeature[effect-5]
  [effect={width=0.5,wdelta=1.5,extend=1.2}]

\definefont
  [EffectiveFontA]
  [BenchMark*default,effect-4 @ 12pt]

\definefont
  [EffectiveFontB]
  [BenchMark*default,effect-5 @ 12pt]
\stopbuffer

\typebuffer \getbuffer

\startlinecorrection[2*big]
\scale[width=\textwidth]{\darkgray\showglyphs \EffectiveFontA effect \EffectiveFontB effect}
\stoplinecorrection

\page

\startbuffer
\definefontfeature[effect-6]
  [effect={width=0.5,wdelta=1.50}]

\definefontfeature[effect-7]
  [effect={width=0.5,wdelta=1.50,squeeze=1.2}]

\definefont
  [EffectiveFontA]
  [BenchMark*default,effect-6 @ 12pt]

\definefont
  [EffectiveFontB]
  [BenchMark*default,effect-7 @ 12pt]
\stopbuffer

\typebuffer \getbuffer

\startlinecorrection[2*big]
\scale[width=\textwidth]{\darkgray\showglyphs \EffectiveFontA effect \EffectiveFontB effect}
\stoplinecorrection

\stoptitle

\starttitle[title=How about math]

\startitemize
\startitem
    I never really needed this kind of trickery but it might be handy for
    bold math in titles.
\stopitem
\startitem
    But math is kind of special as it has extensibles, uses rules and is controlled
    by math parameters.
\stopitem
\startitem
    Math parameters are global for a formula so that doesn't work out well for mixed
    families using fonts with different design parameters.
\stopitem
\stopitemize

\page

\starttyping
\switchtobodyfont[modern]

$\sqrt{\frac{\frac{1}{a}}{\frac{2}{b}}}$

\switchtobodyfont[modernlatin]

$\mr \sqrt{\frac{\frac{1}{a}}{\frac{2}{b}}}$
$\mb \sqrt{\frac{\frac{1}{a}}{\frac{2}{b}}}$
\stoptyping

\startlinecorrection
\startcombination[3*1]
    {\maincolor\switchtobodyfont     [modern]\scale[height=.25\textwidth]{$\sqrt{\frac{\frac{1}{a}}{\frac{2}{b}}}$}} {\tttf latinmodern}
    {\maincolor\switchtobodyfont[modernlatin]\scale[height=.25\textwidth]{$\sqrt{\frac{\frac{1}{a}}{\frac{2}{b}}}$}} {\tttf modernlatin}
    {\maincolor\switchtobodyfont[modernlatin]\scale[height=.25\textwidth]{$\sqrt{\frac{\frac{1}{a}}{\frac{2}{b}}}$}} {\tttf modernlatin}
\stopcombination
\stoplinecorrection

\stoptitle

\starttitle[title=Is it useful]

\startitemize
\startitem
    \start \definedfont[BenchMark*default]%
    For reading on a different medium than paper a bit bolder font often
    works better. This is a normal Latin Modern.\stop
\stopitem
\startitem
    Here we use the \type {modernlatin} For reading on a different medium than
    paper a bit bolder font often works better.
\stopitem
\startitem
    In my opinion a slightly bolder Latin Modern looks a bit more modern, but
    that's of course just an opinion.
\stopitem
\startitem
    I'm not sure if and when I will use this new trickery; maybe to compensate the
    lack of bold math fonts.
\stopitem
\startitem
    Performance wise there is no penalty. File don't get larger. Rendering seems to
    be somewhat slower.
\stopitem
\startitem
    In the end it's probably just another example of feature creep or \TEX\ hobbyism.
\stopitem
\stopitemize

\stoptitle

\starttitle[title=Kerning]

\startMPinclusions
    def SampleShapes(expr dx, offset, pw, k) =
        picture p ; p := image (
            draw               fullcircle scaled 1cm                   withcolor "maincolor" ;
            draw               fullsquare scaled 1cm  shifted (dx+k,0) withcolor "maincolor" ;
            draw point 8   of (fullcircle scaled 1cm)                  withcolor white ;
            draw point 3.5 of (fullsquare scaled 1cm) shifted (dx+k,0) withcolor white ;
        ) shifted (offset,0) ;
        draw p withpen pencircle scaled pw ;
        draw boundingbox p withcolor white ;
    enddef ;
\stopMPinclusions

\startitemize
\startitem
    To what extent do we need to compensate dimensions in order to get the kerning
    acceptable.
\stopitem
\startitem
    Messing around with font features is fragile because there is not much consistency in
    how these are organized.
\stopitem
\stopitemize

\startlinecorrection[2*big]
\startMPcode
    SampleShapes(15mm,  0mm,1mm,0mm) ;
    SampleShapes(15mm, 40mm,2mm,0mm) ;
    SampleShapes(17mm, 80mm,2mm,0mm) ;
\stopMPcode
\stoplinecorrection

\startlinecorrection[2*big]
\startMPcode
    SampleShapes(15mm,  0mm,1mm,0mm) ;
    SampleShapes(15mm, 40mm,2mm,2mm) ;
    SampleShapes(17mm, 80mm,2mm,2mm) ;
\stopMPcode
\stoplinecorrection

\startlinecorrection[2*big]
\startMPcode
    SampleShapes(10mm,  0mm,1mm,0mm) ;
    SampleShapes(10mm, 40mm,1mm,1mm) ;
    SampleShapes(10mm, 80mm,2mm,0mm) ;
    SampleShapes(10mm,120mm,2mm,2mm) ;
\stopMPcode
\stoplinecorrection

\stoptitle

\starttitle[title=Ligatures]

\definefontfeature
  [demo-1]
  [default]
  [hlig=yes]

\definefontfeature
  [demo-2]
  [demo-1]
  [effect=0.5]

\startitemize
\startitem
    Ligatures are even less predictable so this is why we cannot apply too much
    effect.
\stopitem
\startitem
    There can be artifacts due to the way characters are combined (like in Latin
    Modern).
\stopitem
\stopitemize

\startlinecorrection
\startcombination[1*3]
    { \scale [width=.8\textwidth] {
        \definedfont[texgyrepagellaregular*demo-1]fist effe
        \par
        \definedfont[texgyrepagellaregular*demo-2]fist effe
    } } {
        \tttf \maincolor texgyre pagella regular
    } { \scale [width=.8\textwidth] {
        \definedfont[cambria*demo-1]fist effe
        \par
        \definedfont[cambria*demo-2]fist effe
    } } {
        \tttf \maincolor cambria
    } { \scale [width=.8\textwidth] {
        \definedfont[ebgaramond12regular*demo-1]fist effe
        \par
        \definedfont[ebgaramond12regular*demo-2]fist effe
    } } {
        \tttf \maincolor ebgaramond 12 regular
    }
\stopcombination
\stoplinecorrection

\stoptitle

\starttitle[title=Finetuning]

\startbuffer
\definefontfeature[lm-bald]
  [effect={width=0.25,effect=both}]
\definefontfeature[pg-bald]
  [effect={width=0.25,effect=both}]
\definefontfeature[dj-bald]
  [effect={width=0.35,effect=both}]

\definefontfeature[lm-bold]
  [effect={width=0.25,hdelta=0,ddelta=0,effect=both,
    extend=1.10}]

\definefontfeature[pg-bold]
  [effect={width=0.25,hdelta=0,ddelta=0,effect=both,
    extend=1.00}]

\definefontfeature[dj-bold]
  [effect={width=0.35,hdelta=0,ddelta=0,effect=both,
    extend=1.05}]
\stopbuffer

\definefont[lmbald][Serif*default,lm-bald sa d]
\definefont[pgbald][Serif*default,pg-bald sa d]
\definefont[djbald][Serif*default,dj-bald sa d]

\definefont[lmbold][Serif*default,lm-bold sa d]
\definefont[pgbold][Serif*default,pg-bold sa d]
\definefont[djbold][Serif*default,dj-bold sa d]

\typebuffer \getbuffer

\page

\starttabulate[|l|l|l|l|]
\NC
    \NC
    \tt \maincolor modern  \NC
    \tt \maincolor pagella \NC
    \tt \maincolor dejavu  \NC
\NR
\NC
    \maincolor \type{\tfd} \NC
    \switchtobodyfont [modern,24pt]\strut\ruledhbox{\tfd    ABC}\NC
    \switchtobodyfont[pagella,24pt]\strut\ruledhbox{\tfd    ABC}\NC
    \switchtobodyfont [dejavu,24pt]\strut\ruledhbox{\tfd    ABC}\NC
\NR
\NC
    \maincolor \type{\..bald} \NC
    \switchtobodyfont [modern,24pt]\strut\ruledhbox{\lmbald ABC}\NC
    \switchtobodyfont[pagella,24pt]\strut\ruledhbox{\pgbald ABC}\NC
    \switchtobodyfont [dejavu,24pt]\strut\ruledhbox{\djbald ABC}\NC
\NR
\NC
    \maincolor \type{\bfd} \NC
    \switchtobodyfont [modern,24pt]\strut\ruledhbox{\bfd    ABC}\NC
    \switchtobodyfont[pagella,24pt]\strut\ruledhbox{\bfd    ABC}\NC
    \switchtobodyfont [dejavu,24pt]\strut\ruledhbox{\bfd    ABC}\NC
\NR
\NC
    \maincolor \type{\..bold} \NC
    \switchtobodyfont [modern,24pt]\strut\ruledhbox{\lmbold ABC}\NC
    \switchtobodyfont[pagella,24pt]\strut\ruledhbox{\pgbold ABC}\NC
    \switchtobodyfont [dejavu,24pt]\strut\ruledhbox{\djbold ABC}\NC
\NR
\stoptabulate

\stoptitle

\starttitle[title=Pagella]

\startbuffer
\definefontfeature
  [pg-fake-1]
  [effect={width=0.25,effect=both}]

\definefontfeature
  [pg-fake-2]
  [effect={width=0.25,hdelta=0,ddelta=0,effect=both}]

\definefont[pgregular]  [Serif*default]
\definefont[pgbold]     [SerifBold*default]
\definefont[pgfakebolda][Serif*default,pg-fake-1]
\definefont[pgfakeboldb][Serif*default,pg-fake-2]

\definecolor[color-pgregular]  [t=.5,a=1,r=.6]
\definecolor[color-pgbold]     [t=.5,a=1,g=.6]
\definecolor[color-pgfakebolda][t=.5,a=1,b=.6]
\definecolor[color-pgfakeboldb][t=.5,a=1,r=.6,g=.6]
\stopbuffer

\typebuffer

\page

\startbuffer[sample]

\start \switchtobodyfont[pagella]  \getbuffer

\startcombination[2*2]
    {
        \scale [width=\measure{combination}] {
            \ruledhbox{\showglyphs\pgregular   \SampleWord}
        }
    } {
        regular
    } {
        \scale [width=\measure{combination}] {
            \ruledhbox{\showglyphs\pgbold      \SampleWord}
        }
    } {
        bold
    } {
        \scale [width=\measure{combination}] {
            \ruledhbox{\showglyphs\pgfakebolda \SampleWord}
        }
    } {
        fakebolda
    } {
        \scale [width=\measure{combination}] {
            \ruledhbox{\showglyphs\pgfakeboldb \SampleWord}
        }
    } {
        fakeboldb
    }
\stopcombination

\stop

\page

\start \switchtobodyfont[pagella]  \getbuffer

\startcombination[2*3]
    {
        \scale [width=.35\textwidth] {
            \startoverlay
                {\color[color-pgregular]  {\pgregular   \SampleWord}}
                {\color[color-pgbold]     {\pgbold      \SampleWord}}
            \stopoverlay
        }
    } {
        bold over regular
    } {
        \scale [width=.35\textwidth] {
            \startoverlay
                {\color[color-pgregular]  {\pgregular   \SampleWord}}
                {\color[color-pgfakeboldb]{\pgfakeboldb \SampleWord}}
            \stopoverlay
        }
    } {
        fakebolda over regular
    } {
        \scale [width=.35\textwidth] {
            \startoverlay
                {\color[color-pgregular]  {\pgregular   \SampleWord}}
                {\color[color-pgfakebolda]{\pgfakeboldb \SampleWord}}
            \stopoverlay
        }
    } {
        fakeboldb over regular
    } {
        \scale [width=.35\textwidth] {
            \startoverlay
                {\color[color-pgbold]     {\pgbold      \SampleWord}}
                {\color[color-pgfakeboldb]{\pgfakeboldb \SampleWord}}
            \stopoverlay
        }
    } {
        fakeboldb over bold
    } {
        \scale [width=.35\textwidth] {
            \startoverlay
                {\color[color-pgfakebolda]{\pgfakebolda \SampleWord}}
                {\color[color-pgfakeboldb]{\pgfakeboldb \SampleWord}}
            \stopoverlay
        }
    } {
         fakeboldb over fakebolda
    } {
        \scale [width=.35\textwidth] {
            \startoverlay
                {\color[color-pgregular]  {\pgregular   \SampleWord}}
                {\color[color-pgbold]     {\pgbold      \SampleWord}}
                {\color[color-pgfakebolda]{\pgfakebolda \SampleWord}}
                {\color[color-pgfakeboldb]{\pgfakeboldb \SampleWord}}
            \stopoverlay
        }
    } {
         all four overlayed
    }
\stopcombination

\stop

\stopbuffer

\def\SampleWord{\^o\"ep\c s}    \getbuffer[sample]
\def\SampleWord{London Grammar} \getbuffer[sample]

\stoptitle

\starttitle[title=Arabic]

\startbuffer
\definefontfeature
  [bolden-arabic-1]
  [effect={width=0.4}]

\definefontfeature
  [bolden-arabic-2]
  [effect={width=0.4,effect=outer}]

\definefontfeature
  [bolden-arabic-3]
  [effect={width=0.5,wdelta=0.5,ddelta=.2,hdelta=.2,factor=.1}]
\stopbuffer

\typebuffer \getbuffer

\startbuffer

\setupalign
  [righttoleft]

\setupinterlinespace
  [1.5]

\start
  \definedfont[arabictest*arabic,bolden-arabic-1 @ 30pt]
  \samplefile{khatt-ar}\blank
  \definedfont[arabictest*arabic,bolden-arabic-2 @ 30pt]
  \samplefile{khatt-ar}\blank
  \definedfont[arabictest*arabic,bolden-arabic-3 @ 30pt]
  \samplefile{khatt-ar}\blank
\stop
\stopbuffer

\page \start \definefontsynonym[arabictest][arabtype] \getbuffer\stop

\page \start \definefontsynonym[arabictest][husayni]  \getbuffer\stop

\stoptitle

\starttitle[title=Marks and cursive]

\startitemize
\startitem
    Marks are tricky because they can be anchored at any location and we can
    only guess what should be done.
\stopitem
\startitem
    Cursive connections still need to connect and we don't know in advance
    how shapes overlap.
\stopitem
\stopitemize

\startMPinclusions
    def DrawShapes(expr how) =
        def SampleShapes(expr offset, pw, xc, xs, xt, yc, ys, yt, txt, more) =
            numeric l ; l := pw * mm ;
            picture p ; p := image (
                draw fullcircle   scaled 10 ;
                draw fullcircle   scaled  3 shifted (-3+xc  ,8+yc) withcolor "darkred" ;
                draw fullsquare   scaled  3 shifted ( 6+xs  ,7+ys) withcolor "darkblue";
                draw fulltriangle scaled  4 shifted ( 6+xt+5,6+yt) withcolor "darkgreen";
            ) shifted (offset,0) scaled mm ;
            draw p
                withpen pencircle
                    if how = 2 :
                        xscaled l yscaled (l/2) rotated 30 ;
                    else :
                        scaled l ;
                    fi ;
            draw boundingbox p
                withcolor "darkyellow" ;
            draw textext(txt)
                shifted (xpart center p, -8mm) ;
            draw textext(more)
                shifted (xpart center p, -11mm) ;
        enddef ;
        SampleShapes(  0,1, 0,0,0, 0,   0,   0,  "\tinyfont \setstrut \strut original",   "\tinyfont \setstrut \strut ") ;
        SampleShapes( 25,2, 0,0,0, 0,   0,   0,  "\tinyfont \setstrut \strut instance",   "\tinyfont \setstrut \strut ") ;
        SampleShapes( 50,2,-1,1,0, 0,   0,   0,  "\tinyfont \setstrut \strut mark",       "\tinyfont \setstrut \strut x only") ;
        SampleShapes( 75,2,-1,1,1, 0,   0,   0,  "\tinyfont \setstrut \strut mark + mkmk","\tinyfont \setstrut \strut x only") ;
        SampleShapes(100,2,-1,1,1, 1,   1,   1,  "\tinyfont \setstrut \strut mark + mkmk","\tinyfont \setstrut \strut x and y") ;
        SampleShapes(125,2,-1,2,2,-1/2,-1/2,-1/2,"\tinyfont \setstrut \strut mark + mkmk","\tinyfont \setstrut \strut x and -y") ;
    enddef ;
\stopMPinclusions

\startlinecorrection[2*big]
\scale
  [width=\textwidth]
  {\startMPcode DrawShapes(1) ; \stopMPcode}
\stoplinecorrection

\startlinecorrection[2*big]
\scale
  [width=\textwidth]
  {\startMPcode DrawShapes(2) ; \stopMPcode}
\stoplinecorrection

\stoptitle

\starttitle[title=Radicals and such]

Radicals are constructed using rules and extensible characters. Especially the rules
need to be adapted.

\startbuffer[mathblob]
\def\MathSample
  {2\times\sqrt{\frac{\sqrt{\frac{\sqrt{2}}{\sqrt{2}}}}
     {\sqrt{\frac{\sqrt{2}}{\sqrt{2}}}}}}
\stopbuffer

\startbuffer
$\mr \darkblue  \MathSample \quad
 \mb \darkgreen \MathSample $
\stopbuffer

\getbuffer[mathblob]

\typebuffer

\startlinecorrection[blank]
\scale[width=\textwidth]{\switchtobodyfont[modernlatin,24pt]\getbuffer}
\stoplinecorrection

\page

\startbuffer
\dostepwiserecurse {1} {30} {5} {
  $
    \mr \sqrt{\blackrule[width=2mm,height=#1mm,color=darkblue]}
    \quad
    \mb \sqrt{\blackrule[width=2mm,height=#1mm,color=darkgreen]}
  $
}
\stopbuffer

\typebuffer

\startlinecorrection[blank]
\scale[width=\textwidth]{\switchtobodyfont[modernlatin,24pt]\getbuffer}
\stoplinecorrection

\page

\definecolor[colormr] [t=.5,a=1,b=.6]
\definecolor[colormb] [t=.5,a=1,g=.6]

% and a fix in \LUATEX: pickup the value from the font instead of the currently

\startlinecorrection
\midaligned{\scale[height=.6\textheight]{\startoverlay
    {\color[colormb]{$\mb\sqrt{\frac{1}{x}}$}}
    {\color[colormr]{$   \sqrt{\frac{1}{x}}$}}
\stopoverlay}}
\stoplinecorrection

\page

\unexpanded\def\ShowMathSample#1%
  {\switchtobodyfont[#1,14.4pt]%
   \mathematics{%
    \mr \darkblue  \MathSample \quad
    \mb \darkgreen \MathSample
   }}

\unexpanded\def\ShowMathCaption#1%
  {\switchtobodyfont[#1]%
   #1:
   $
   {\mr2\enspace \scriptstyle2\enspace \scriptscriptstyle2}
   \enspace
   {\mb2\enspace \scriptstyle2\enspace \scriptscriptstyle2}
   $}

\midaligned{\startcombination[3*2]
    {\ShowMathSample {dejavu}} {\ShowMathCaption{dejavu}}
    {\ShowMathSample{pagella}} {\ShowMathCaption{pagella}}
    {\ShowMathSample {termes}} {\ShowMathCaption{termes}}
    {\ShowMathSample  {bonum}} {\ShowMathCaption{bonum}}
    {\ShowMathSample {schola}} {\ShowMathCaption{schola}}
    {\ShowMathSample{cambria}} {\ShowMathCaption{cambria}}
\stopcombination}

\page

\starttyping
\definefontfeature
  [boldened-30]
  [effect={width=0.3,extend=1.15,squeeze=0.985,%
    delta=1,hdelta=0.225,ddelta=0.225,vshift=0.225}]

\definefontfeature
  [boldened-30]
  [effect={width=0.30,auto=yes}]
\stoptyping

\stoptitle

\starttitle[title=An application]

\def\MathSample
  {\overbrace{2 +
     \sqrt{\frac{\sqrt{\frac{\sqrt{2}}{\sqrt{2}}}}
       {\sqrt{\frac{\sqrt{\underbar{2}}}{\sqrt{\overbar{2}}}}}}}}

\startbuffer
\definehead [mysectiona] [section]
\definehead [mysectionb] [mysectiona]

\setuphead
  [mysectiona]
  [style=\tfc,
   color=darkblue,
   before=\blank,
   after=\blank]

\setuphead
  [mysectionb]
  [style=\bfc,
   color=darkred]

\mysectiona{Regular\quad$\MathSample\quad\mb\MathSample$}
\mysectionb{Bold   \quad$\MathSample\quad\mb\MathSample$}
\stopbuffer

\typebuffer \page \getbuffer \page

\startcolumns
    \switchtobodyfont[modern,12pt]      \setupinterlinespace[15pt] \samplefile{poe} \column
    \switchtobodyfont[modernlatin,12pt] \setupinterlinespace[15pt] \samplefile{poe} % \column
\stopcolumns

\stoptitle

\stoptext