8 files changed, 944 insertions, 0 deletions
diff --git a/doc/context/presentations/bachotex/2017/bachotex-2017-emoji-demo.pdf b/doc/context/presentations/bachotex/2017/bachotex-2017-emoji-demo.pdf
new file mode 100644
index 000000000..cce61e1b3
--- /dev/null
+++ b/doc/context/presentations/bachotex/2017/bachotex-2017-emoji-demo.pdf
diff --git a/doc/context/presentations/bachotex/2017/bachotex-2017-emoji-demo.tex b/doc/context/presentations/bachotex/2017/bachotex-2017-emoji-demo.tex
new file mode 100644
index 000000000..ada27160b
--- /dev/null
+++ b/doc/context/presentations/bachotex/2017/bachotex-2017-emoji-demo.tex
@@ -0,0 +1,26 @@
+\starttext
+
+\definefontfeature
+  [seguiemj-cl]
+  [default]
+  [colr=yes,
+   ccmp=yes,
+   dist=yes]
+
+\definefont
+  [MyEmoji]
+  [seguiemj*seguiemj-cl]
+
+\typefile{emoji-demo-001.tex}
+
+\showotfcomposition
+  {seguiemj*seguiemj-cl}
+  {1}
+  {\resolvedemoji
+     {family
+      man light skin tone
+      woman dark skin tone
+      girl medium skin tone
+      boy medium skin tone}}
+
+\stoptext
diff --git a/doc/context/presentations/bachotex/2017/bachotex-2017-emoji.pdf b/doc/context/presentations/bachotex/2017/bachotex-2017-emoji.pdf
new file mode 100644
index 000000000..d7e01f59c
--- /dev/null
+++ b/doc/context/presentations/bachotex/2017/bachotex-2017-emoji.pdf
diff --git a/doc/context/presentations/bachotex/2017/bachotex-2017-emoji.tex b/doc/context/presentations/bachotex/2017/bachotex-2017-emoji.tex
new file mode 100644
index 000000000..c6deb3873
--- /dev/null
+++ b/doc/context/presentations/bachotex/2017/bachotex-2017-emoji.tex
@@ -0,0 +1,374 @@
+% language=uk
+
+\setuppapersize
+  [S6]
+
+\setupbackgrounds
+  [page]
+  [background=color,
+   backgroundcolor=darkgray]
+
+\setuplayout
+  [backspace=24pt,
+   topspace=20pt,
+   bottomspace=8pt,
+   width=middle,
+   height=middle,
+   footerdistance=8pt,
+   footer=8pt,
+   header=0pt]
+
+\setupcolors
+  [textcolor=white]
+
+\setupbodyfont
+  [dejavu,14.4pt]
+
+\definecolor[trace:o] [s=1]
+\definecolor[trace:r] [s=1]
+\definecolor[trace:do][s=1]
+\definecolor[trace:dr][s=1]
+
+\usemodule[abr-03]
+
+\definefontfeature[noligatures][liga=no]
+
+\setuphead
+  [section]
+  [page=yes,
+   style=\bfb,
+   after={\blank[3*medium]}]
+
+\setuphead
+  [subsection]
+  [page=no,
+   style=\bf\addfeature{noligatures},
+   before={\blank[3*medium]},
+   after={\blank}]
+
+\setupfooter
+  [strut=no,
+   style=\bf]
+
+\startdocument
+  [title={Picture Fonts},
+   subtitle={welcome to a (beautiful) mess},
+   author={Hans Hagen},
+   occasion={BachoTUG 2017}]
+
+\startstandardmakeup
+    \vskip32pt
+    \bfd \setupinterlinespace
+    \documentvariable{title}
+    \crlf
+    \bfb \setupinterlinespace
+    \vskip12pt
+    \documentvariable{subtitle}
+    \vfill
+    \bfb \setupinterlinespace
+    \documentvariable{author}
+    \crlf
+    \documentvariable{occasion}
+\stopstandardmakeup
+
+\startsubject[title=A Summary]
+
+\startitemize
+\startitem
+    {\bf the macro package's view:} just a font like any other but it needs to configure
+    some extra color related properties
+\stopitem
+\startitem
+    {\bf the engine's view:} depending on the technology a normal font that needs a bit
+    special treatment or needs to be dealt with as collection of graphics
+\stopitem
+\startitem
+    {\bf the viewer's view:} regular outline glyphs or images tagged as kind of
+    characters so that their unicode representation can be cut and paste
+\stopitem
+\startitem
+    {\bf the user's view:} more pictures than glyphs although some people one can
+    communicate using them
+\stopitem
+\stopitemize
+
+So, in practice, for most \TEX\ users it's probably not a high priority font but more a fun
+one.
+
+\stopsubject
+
+\startsubject[title=Technologies]
+
+As each vendor came up with something, we have to deal with a all kinds of formats. And or
+course, as eagerness pushes things on the market before it's perfect we now have to deal
+with all of them.
+
+\startitemize
+\startitem
+    {\bf overlapping glyphs:} this technique uses the \type {colr} and \type {cpal} tables
+    and is actually a quite clean technology, you can combine in different ways
+\stopitem
+\startitem
+    {\bf svg graphics:} this technique uses the \type {svg} table that contains a svg vector
+    image
+\stopitem
+\startitem
+    {\bf bitmap graphics:} this technique uses for instance \type {sbix} tables that can have
+    various graphic images
+\stopitem
+\stopitemize
+
+The first two are already supported in the \CONTEXT\ font loader and processor
+for a while, the last one was added recently.
+
+\blank
+
+Only the overlapping method is useable for the tens of thousands of skin tone combinations of
+families, (kissing) couples, and professions.
+
+\stopsubject
+
+\startsubject[title=Preparation]
+
+For now one has to enable the feature:
+
+\startbuffer
+\definefontfeature[overlay][default][ccmp=yes,colr=yes,dist=yes]
+\definefontfeature[svg]    [default][svg=yes]
+\definefontfeature[bitmap] [default][sbix=yes]
+
+\definefontfeature [colored] [default]
+  [cmcp=yes,dist=yes,
+   colr=yes,svg=yes,sbix=yes]
+\stopbuffer
+
+\typebuffer \getbuffer
+
+Defining a font is not different from others
+
+\starttyping
+\definefont[MyEmojiFont] [seguiemj*overlay]
+\definefontsynonym[emoji][seguiemj*overlay]
+\stoptyping
+
+As is using:
+
+\starttyping
+{\MyEmojiFont\resolvedemoji{woman}}
+\emoji{woman}
+\stoptyping
+
+\stopsubject
+
+\startsubject[title=Accessing shapes]
+
+\startbuffer
+\definesymbol[man]  [\emoji{man}]
+\definesymbol[woman][\emoji{woman}]
+\definesymbol[girl] [\emoji{girl}]
+\definesymbol[boy]  [\emoji{boy}]
+
+\definesymbol[family][\emoji{family man woman girl boy}]
+\stopbuffer
+
+\typebuffer \getbuffer
+
+\starttyping
+\definefontsynonym[emoji][file:seguiemj.ttf*default,overlay]
+
+\symbol[boy] \symbol[girl] \symbol[man] \symbol[woman]
+
+\symbol[family]
+\stoptyping
+
+\stopsubject
+
+\startsubject[title=Different fonts]
+
+\def\ShowThem#1#2#3%
+  {\NC #1
+   \NC default
+   \NC \definefontsynonym[emoji][#3*default]\symbol[boy] \symbol[girl] \symbol[man] \symbol[woman]
+   \NC \definefontsynonym[emoji][#3*default]\symbol[family]
+   \NC \NR
+   \NC
+   \NC #2
+   \NC \definefontsynonym[emoji][#3*#2]\symbol[boy] \symbol[girl] \symbol[man] \symbol[woman]
+   \NC \definefontsynonym[emoji][#3*#2]\symbol[family]
+   \NC \NR}
+
+\starttabulate[|T|T|||]
+    \ShowThem{seguiemj}             {overlay}{file:seguiemj.ttf}
+    \ShowThem{emojionecolor-svginot}{svg}    {file:emojionecolor-svginot.ttf}
+    \ShowThem{emojionemozilla}      {overlay}{file:emojionemozilla.ttf}
+    \ShowThem{applecoloremoji}      {bitmap} {file:applecoloremoji.ttc}
+\stoptabulate
+
+\stopsubject
+
+\startsubject[title=Ligatures]
+
+\definefontfeature[seguiemj-cl][default][colr=yes,ccmp=yes,dist=yes]
+\definefontfeature[seguiemj-bw][default][ccmp=yes]
+
+% \definefont[MyEmoji][emojionecolor-svginot*default,svg]
+% \definefont[MyEmoji][seguiemj*seguiemj-bw]
+\definefont[MyEmoji][seguiemj*seguiemj-cl]
+% \definefont[MyEmoji][emojionemozilla*default,overlay]
+% \definefont[MyEmoji][applecoloremoji*default,bitmap]
+
+{\MyEmoji 👨🏽‍🌾 👨🏽‍🍳 👨🏽‍🎓 👨🏽‍🎤 👨🏽‍🎨 👨🏽‍🏫 👨🏽‍🏭 👨🏽‍💻 👨🏽‍💼 👨🏽‍🔧 👨🏽‍🔬 👨🏽‍🚀}
+
+\starttabulate[|T|T||]
+\NC character         \NC 1F477       \NC \MyEmoji \utfchar{"1F477} \NC \NR % construction worker
+\NC skin modifier     \NC 1F3FE       \NC \MyEmoji \utfchar{"1F3FE} \NC \NR % medium dark skin
+\NC ligature          \NC 1F477 1F3FE \NC \MyEmoji \utfchar{"1F477}%
+                                                   \utfchar{"1F3FE} \NC \NR
+\NC zero width joiner \NC 0200D       \NC \MyEmoji \utfchar{"0200D} \NC \NR
+\NC female modifier   \NC 02640 0FE0F \NC \MyEmoji \utfchar{"02640}%
+                                                   \utfchar{"0FE0F} \NC \NR
+\NC the whole lot     \NC             \NC \MyEmoji \utfchar{"1F477}%
+                                                   \utfchar{"1F3FE}%
+                                                   \utfchar{"0200D}%
+                                                   \utfchar{"02640}%
+                                                   \utfchar{"0FE0F} \NC \NR
+\stoptabulate
+
+\starttabulate[|T|T||]
+\NC 1F468 1F3FD 200D 1F33E \NC \MyEmoji 👨🏽‍🌾 \NC man farmer          medium skin tone \NC \NR
+\NC 1F468 1F3FD 200D 1F373 \NC \MyEmoji 👨🏽‍🍳 \NC man cook            medium skin tone \NC \NR
+\NC 1F468 1F3FD 200D 1F393 \NC \MyEmoji 👨🏽‍🎓 \NC man student         medium skin tone \NC \NR
+\NC 1F468 1F3FD 200D 1F3A4 \NC \MyEmoji 👨🏽‍🎤 \NC man singer          medium skin tone \NC \NR
+\NC 1F468 1F3FD 200D 1F3A8 \NC \MyEmoji 👨🏽‍🎨 \NC man artist          medium skin tone \NC \NR
+\NC 1F468 1F3FD 200D 1F3EB \NC \MyEmoji 👨🏽‍🏫 \NC man teacher         medium skin tone \NC \NR
+\NC 1F468 1F3FD 200D 1F3ED \NC \MyEmoji 👨🏽‍🏭 \NC man factory worker  medium skin tone \NC \NR
+\NC 1F468 1F3FD 200D 1F4BB \NC \MyEmoji 👨🏽‍💻 \NC man technologist    medium skin tone \NC \NR
+\NC 1F468 1F3FD 200D 1F4BC \NC \MyEmoji 👨🏽‍💼 \NC man office worker   medium skin tone \NC \NR
+\NC 1F468 1F3FD 200D 1F527 \NC \MyEmoji 👨🏽‍🔧 \NC man mechanic        medium skin tone \NC \NR
+\NC 1F468 1F3FD 200D 1F52C \NC \MyEmoji 👨🏽‍🔬 \NC man scientist       medium skin tone \NC \NR
+\NC 1F468 1F3FD 200D 1F680 \NC \MyEmoji 👨🏽‍🚀 \NC man astronaut       medium skin tone \NC \NR
+\stoptabulate
+
+\stopsubject
+
+\usemodule[fonts-emoji]
+
+\startsubject[title=Snippets]
+
+\start
+
+    \definedfont[seguiemj*seguiemj-cl @ 32pt]
+
+    \ShowEmojiSnippets
+        [family man light skin tone woman dark skin tone girl medium skin tone boy medium skin tone]
+
+    \vskip1ex
+
+    \ShowEmojiSnippetsOverlay
+        [family man light skin tone woman dark skin tone girl medium skin tone boy medium skin tone]
+
+    \vskip1ex
+
+    \ShowEmojiGlyphs
+        [family man light skin tone woman dark skin tone girl medium skin tone boy medium skin tone]
+
+\stop
+
+\stopsubject
+
+\startsubject[title=Using \type{\ShowEmoji[^man]}]
+
+\start
+
+    \MyEmoji
+
+    \ShowEmoji[^man]
+
+\stop
+
+\stopsubject
+
+\startsubject[title=Recoloring Seguiem]
+
+\start
+
+\definecolor[emoji-red]   [r=.4]
+\definecolor[emoji-blue]  [b=.4]
+\definecolor[emoji-yellow][y=.4]
+\definecolor[emoji-gray]  [s=.5,t=.5,a=1]
+
+\definefontcolorpalette
+  [emoji-red]
+  [emoji-red,emoji-gray]
+
+\definefontcolorpalette
+  [emoji-blue]
+  [emoji-blue,emoji-gray]
+
+\definefontcolorpalette
+  [emoji-yellow]
+  [emoji-yellow,emoji-gray]
+
+\definefontfeature[seguiemj-r][default][ccmp=yes,dist=yes,colr=emoji-red]
+\definefontfeature[seguiemj-b][default][ccmp=yes,dist=yes,colr=emoji-blue]
+\definefontfeature[seguiemj-y][default][ccmp=yes,dist=yes,colr=emoji-yellow]
+
+\definefont[MyColoredEmojiR][seguiemj*seguiemj-r @ 80pt]
+\definefont[MyColoredEmojiB][seguiemj*seguiemj-b @ 80pt]
+\definefont[MyColoredEmojiY][seguiemj*seguiemj-y @ 80pt]
+
+\MyColoredEmojiR
+    \resolvedemoji{man}
+    \resolvedemoji{woman}
+    \resolvedemoji{baby}
+
+\vskip24pt
+
+\MyColoredEmojiB
+    \resolvedemoji{triangular ruler}
+    \resolvedemoji{rabbit face}
+    \resolvedemoji{family man woman girl boy}
+
+\vskip24pt
+
+\MyColoredEmojiY
+    \resolvedemoji{triangular ruler}
+    \resolvedemoji{rabbit face}
+    \resolvedemoji{family man woman girl boy}
+
+\stop
+
+\page
+
+\starttyping
+\definecolor [emoji-red]  [r=.4]
+\definecolor [emoji-gray] [s=.5,t=.5,a=1]
+
+\definefontcolorpalette
+  [emoji-red]
+  [emoji-red,emoji-gray]
+
+\definefontfeature
+  [seguiemj-r]
+  [default]
+  [ccmp=yes,dist=yes,colr=emoji-red]
+
+\definefont
+  [MyColoredEmojiR]
+  [seguiemj*seguiemj-r @ 80pt]
+
+\MyColoredEmojiR
+    \emoji{man}
+    \emoji{woman}
+    \emoji{baby}
+\stoptyping
+
+\stopsubject
+
+\startsubject[title=Pallet \type{\ShowEmojiPalettes[1]}]
+
+{\MyEmoji \ShowEmojiPalettes[1]}
+
+\stopsubject
+
+\stopdocument
diff --git a/doc/context/presentations/bachotex/2017/bachotex-2017-variablefonts-demo.pdf b/doc/context/presentations/bachotex/2017/bachotex-2017-variablefonts-demo.pdf
new file mode 100644
index 000000000..bac8d54c1
--- /dev/null
+++ b/doc/context/presentations/bachotex/2017/bachotex-2017-variablefonts-demo.pdf
diff --git a/doc/context/presentations/bachotex/2017/bachotex-2017-variablefonts-demo.tex b/doc/context/presentations/bachotex/2017/bachotex-2017-variablefonts-demo.tex
new file mode 100644
index 000000000..e9543a30a
--- /dev/null
+++ b/doc/context/presentations/bachotex/2017/bachotex-2017-variablefonts-demo.tex
@@ -0,0 +1,44 @@
+% macros=mkvi
+
+\usemodule[art-01] \dontcomplain
+
+\starttexdefinition unexpanded TestFont #font#variant#size
+    \bgroup
+        \definedfont[name:#font#variant*default @ #size]
+        \setupinterlinespace
+      % \showstruts
+      % \strut
+        \samplefile{tufte}
+        \par
+    \egroup
+\stoptexdefinition
+
+\starttext
+
+\dorecurse {5} {
+
+    \dostepwiserecurse {8} {14} {1} { % 30 fonts
+        \TestFont {adobevariablefontprototype} {extralight} {##1pt}
+        \TestFont {adobevariablefontprototype} {light}      {##1pt}
+        \TestFont {adobevariablefontprototype} {regular}    {##1pt}
+        \TestFont {adobevariablefontprototype} {semibold}   {##1pt}
+        \TestFont {adobevariablefontprototype} {bold}       {##1pt}
+        \TestFont {adobevariablefontprototype} {black}      {##1pt}
+    }
+
+    \page
+
+  % \dostepwiserecurse {8} {14} {1} { % 40 fonts
+  %     \TestFont {avenirnextvariable} {regular}          {##1pt}
+  %     \TestFont {avenirnextvariable} {medium}           {##1pt}
+  %     \TestFont {avenirnextvariable} {bold}             {##1pt}
+  %     \TestFont {avenirnextvariable} {heavy }           {##1pt}
+  %     \TestFont {avenirnextvariable} {condensed}        {##1pt}
+  %     \TestFont {avenirnextvariable} {medium condensed} {##1pt}
+  %     \TestFont {avenirnextvariable} {bold condensed}   {##1pt}
+  %     \TestFont {avenirnextvariable} {heavy condensed}  {##1pt}
+  % }
+
+}
+
+\stoptext
diff --git a/doc/context/presentations/bachotex/2017/bachotex-2017-variablefonts.pdf b/doc/context/presentations/bachotex/2017/bachotex-2017-variablefonts.pdf
new file mode 100644
index 000000000..ee3537bd2
--- /dev/null
+++ b/doc/context/presentations/bachotex/2017/bachotex-2017-variablefonts.pdf
diff --git a/doc/context/presentations/bachotex/2017/bachotex-2017-variablefonts.tex b/doc/context/presentations/bachotex/2017/bachotex-2017-variablefonts.tex
new file mode 100644
index 000000000..08050a57d
--- /dev/null
+++ b/doc/context/presentations/bachotex/2017/bachotex-2017-variablefonts.tex
@@ -0,0 +1,500 @@
+% language=uk
+
+\setuppapersize
+  [S6]
+
+\setupbackgrounds
+  [page]
+  [background=color,
+   backgroundcolor=darkblue]
+
+\setuplayout
+  [backspace=24pt,
+   topspace=20pt,
+   bottomspace=8pt,
+   width=middle,
+   height=middle,
+   footerdistance=8pt,
+   footer=8pt,
+   header=0pt]
+
+\setupcolors
+  [textcolor=white]
+
+\setupbodyfont
+  [dejavu,14.4pt]
+
+\definecolor[trace:o] [s=1]
+\definecolor[trace:r] [s=1]
+\definecolor[trace:do][s=1]
+\definecolor[trace:dr][s=1]
+
+\usemodule[abr-03]
+
+\definefontfeature[noligatures][liga=no]
+
+\setuphead
+  [section]
+  [page=yes,
+   style=\bfb,
+   after={\blank[3*medium]}]
+
+\setuphead
+  [subsection]
+  [page=no,
+   style=\bf\addfeature{noligatures},
+   before={\blank[3*medium]},
+   after={\blank}]
+
+\setupfooter
+  [strut=no,
+   style=\bf]
+
+\startuseMPgraphic{pagenumber}
+    if LastPageNumber > 0 :
+        draw outlinetext.f
+            (decimal RealPageNumber)
+            (withcolor "darkgray")
+            xysized ((RealPageNumber/LastPageNumber) * TextWidth/2,FooterHeight) ;
+    fi ;
+\stopuseMPgraphic
+
+\setupfootertexts
+  [\useMPgraphic{pagenumber}]
+
+\startdocument
+  [title={Variable Fonts},
+   subtitle={we're ready for them},
+   author={Hans Hagen},
+   occasion={BachoTUG 2017}]
+
+\startstandardmakeup
+    \vskip32pt
+    \bfd \setupinterlinespace
+    \documentvariable{title}
+    \crlf
+    \bfb \setupinterlinespace
+    \vskip12pt
+    \documentvariable{subtitle}
+    \vfill
+    \bfb \setupinterlinespace
+    \documentvariable{author}
+    \crlf
+    \documentvariable{occasion}
+\stopstandardmakeup
+
+\startsubject[title=A Summary]
+
+\startitemize
+\startitem
+    {\bf the macro package's view:} just a font but with many possible variations
+    in shapes (width, weight, slope, etc) and therefore a bit more complex user
+    interface
+\stopitem
+\startitem
+    {\bf the engine's view:} an abstraction not different from other fonts but
+    that needs a special treatment in the backend
+\stopitem
+\startitem
+    {\bf the viewer's view:} a font to be displayed like any other with outlines
+    in cff of ttf format
+\stopitem
+\startitem
+    {\bf the user's view:} an opentype font with possibly surprising shapes of
+    which you need to know a bit more than usual if you want to profit from it
+\stopitem
+\stopitemize
+
+So, in practice, for most \TEX\ users it's just a font that has to be supported by
+\TEX\ and friends.
+
+\stopsubject
+
+\startsubject[title=Starting point]
+
+\startitemize
+\startitem
+    The OpenType 1.8 specification at the MicroSoft website defined the extra
+    tables and explains bits and pieces.
+\stopitem
+\startitem
+    There a few fonts that have relevant tables (not all) and implement variants
+    as well as features.
+\stopitem
+\startitem
+    There are some posts on the internet that show a bit about axis and other things
+    that go on in these fonts.
+\stopitem
+\startitem
+    Luckily we have ways (in \CONTEXT) to explore what goes on in these fonts and
+    how they could look.
+\stopitem
+\startitem
+    Condition: no tricks, no fuzzy heuristics, just the specification should be
+    enough.
+\stopitem
+\stopitemize
+
+\stopsubject
+
+\startsubject[title=Implementation steps]
+
+\startitemize
+\startitem
+    First try to render variants in order to see what we're dealing with. This was not too
+    hard (starting with cff) because we have already virtual font support.
+\stopitem
+\startitem
+    Next try to load the relevant tables and figure out what these deltas and such really
+    mean and how axis and regions and \unknown\ have to be applied.
+\stopitem
+\startitem
+    Try to make it all work on a real piece of text, so not only shapes but also features
+    and dimensions.
+\stopitem
+\startitem
+    Finally make sure that the font can get embedded as a normal font and not as inline
+    (tagged) graphic.
+\stopitem
+\startitem
+    Also, try to generalize the helpers and methods in such ways that we can experiment
+    with additional tricks (after all, \TEX\ is about control).
+\stopitem
+\startitem
+    Todo: once there are more fonts (with the right data tables), check the code with the
+    specification.
+\stopitem
+\stopitemize
+
+\stopsubject
+
+\setupTABLE[c][1][style=tttf,align={flushleft,lohi}]
+
+\startsubject[title=Adobe Variable Font Prototype (cff)]
+
+\unexpanded\def\SampleFont#1#2% weight / contrast
+  {\definedfont[name:adobevariablefontprototype#1*default at 32pt]It looks like this!}
+
+\bTABLE[distance=2em,frame=off]
+\bTR \bTD extralight               0/0   \eTD \bTD \SampleFont {extralight}          \eTD \eTR
+\bTR \bTD light                  150/0   \eTD \bTD \SampleFont {light}               \eTD \eTR
+\bTR \bTD regular                394/0   \eTD \bTD \SampleFont {regular}             \eTD \eTR
+\bTR \bTD semibold               600/0   \eTD \bTD \SampleFont {semibold}            \eTD \eTR
+\bTR \bTD bold                   824/0   \eTD \bTD \SampleFont {bold}                \eTD \eTR
+\bTR \bTD black high contrast   1000/100 \eTD \bTD \SampleFont {blackhighcontrast}   \eTD \eTR
+\bTR \bTD black medium contrast 1000/50  \eTD \bTD \SampleFont {blackmediumcontrast} \eTD \eTR
+\bTR \bTD black                 1000/0   \eTD \bTD \SampleFont {black}               \eTD \eTR
+\eTABLE
+
+\stopsubject
+
+% \starttyping
+% \definefont
+%   [MyLightFont]
+%   [name:adobevariablefontprototypelight*default]
+% \stoptyping
+
+\unexpanded\def\SampleFont#1#2% weight / width
+  {\definedfont[name:avenirnextvariable#1*default at 32pt]It looks like this!}
+
+\startsubject[title=Avenir Next Variable (ttf)]
+
+\bTABLE[distance=2em,frame=off]
+\bTR \bTD regular           400/100 \eTD \bTD \SampleFont {regular}         \eTD \eTR
+\bTR \bTD medium            500/100 \eTD \bTD \SampleFont {medium}          \eTD \eTR
+\bTR \bTD bold              700/100 \eTD \bTD \SampleFont {bold}            \eTD \eTR
+\bTR \bTD heavy             900/100 \eTD \bTD \SampleFont {heavy}           \eTD \eTR
+\bTR \bTD condensed         400/75  \eTD \bTD \SampleFont {condensed}       \eTD \eTR
+\bTR \bTD medium condensed  500/75  \eTD \bTD \SampleFont {mediumcondensed} \eTD \eTR
+\bTR \bTD bold condensed    700/75  \eTD \bTD \SampleFont {boldcondensed}   \eTD \eTR
+\bTR \bTD heavy condensed   900/75  \eTD \bTD \SampleFont {heavycondensed}  \eTD \eTR
+\eTABLE
+
+\stopsubject
+
+\startbuffer[both]
+\vfill
+\startMPcode
+  draw outlinetext.b
+    ("\getbuffer[a]")
+    (withcolor "white")
+    (withcolor "red" withpen pencircle scaled 1/10)
+    xsized .9TextWidth ;
+\stopMPcode
+\vfill
+\startMPcode
+  draw outlinetext.b
+    ("\getbuffer[b]")
+    (withcolor "white")
+    (withcolor "red" withpen pencircle scaled 1/10)
+    xsized .9TextWidth ;
+\stopMPcode
+\vfill
+\startMPcode
+  draw outlinetext.b
+    ("\getbuffer[c]")
+    (withcolor "white")
+    (withcolor "red" withpen pencircle scaled 1/10)
+    xsized .90TextWidth ;
+\stopMPcode
+\vfill
+\stopbuffer
+
+\startbuffer[fill]
+\vfill
+\startMPcode
+  draw outlinetext.f
+    ("\getbuffer[a]")
+    (withcolor "white")
+    xsized .9TextWidth ;
+\stopMPcode
+\vfill
+\startMPcode
+  draw outlinetext.f
+    ("\getbuffer[b]")
+    (withcolor "white")
+    xsized .9TextWidth ;
+\stopMPcode
+\vfill
+\startMPcode
+  draw outlinetext.f
+    ("\getbuffer[c]")
+    (withcolor "white")
+    xsized .9TextWidth ;
+\stopMPcode
+\vfill
+\stopbuffer
+
+\startbuffer[draw]
+\vfill
+\startMPcode
+  draw outlinetext.d
+    ("\getbuffer[a]")
+    (withcolor "white" withpen pencircle scaled 1/10)
+    xsized .9TextWidth ;
+\stopMPcode
+\vfill
+\startMPcode
+  draw outlinetext.d
+    ("\getbuffer[b]")
+    (withcolor "white" withpen pencircle scaled 1/10)
+    xsized .9TextWidth ;
+\stopMPcode
+\vfill
+\startMPcode
+  draw outlinetext.d
+    ("\getbuffer[c]")
+    (withcolor "white" withpen pencircle scaled 1/10)
+    xsized .9TextWidth ;
+\stopMPcode
+\vfill
+\stopbuffer
+
+\startbuffer[overlay]
+\startoverlay{%
+\startMPcode
+  draw outlinetext.d
+    ("\getbuffer[a]")
+    (withcolor "green" withtransparency (3,0.5) withpen pencircle scaled 1/10)
+    xsized .9TextWidth ;
+\stopMPcode
+}{%
+\startMPcode
+  draw outlinetext.d
+    ("\getbuffer[b]")
+    (withcolor "yellow" withtransparency (3,0.5) withpen pencircle scaled 1/10)
+    xsized .9TextWidth ;
+\stopMPcode
+}{%
+\startMPcode
+  draw outlinetext.d
+    ("\getbuffer[c]")
+    (withcolor "red" withtransparency (3,0.5) withpen pencircle scaled 1/10)
+    xsized .9TextWidth ;
+\stopMPcode
+}
+\stopoverlay
+\stopbuffer
+
+\startbuffer[a]
+\definedfont[name:adobevariablefontprototypeextralight]bachotex%
+\stopbuffer
+
+\startbuffer[b]
+\definedfont[name:adobevariablefontprototypelight]bachotex%
+\stopbuffer
+
+\startbuffer[c]
+\definedfont[name:adobevariablefontprototypebold]bachotex%
+\stopbuffer
+
+\startsubject[title=Metafontisch overlap (1)]
+    \getbuffer[both]
+\stopsubject
+
+\startbuffer[a]
+\definefontfeature[whatever][axis={weight:50}]%
+\definedfont[name:adobevariablefontprototype*whatever]bachotex%
+\stopbuffer
+
+\startbuffer[b]
+\definefontfeature[whatever][axis={weight:300}]%
+\definedfont[name:adobevariablefontprototype*whatever]bachotex%
+\stopbuffer
+
+\startbuffer[c]
+\definefontfeature[whatever][axis={weight:700}]%
+\definedfont[name:adobevariablefontprototype*whatever]bachotex%
+\stopbuffer
+
+\startsubject[title=Metafontisch overlap (2)]
+    \getbuffer[both]
+\stopsubject
+\startsubject[title=Fills hide the details]
+    \getbuffer[fill]
+\stopsubject
+\startsubject[title=Unsuitable outlines]
+    \getbuffer[draw]
+\stopsubject
+
+\startbuffer[a]
+\definefontfeature[whatever][axis={weight:100,contrast:0}]%
+\definedfont[name:adobevariablefontprototype*whatever]bachotex%
+\stopbuffer
+
+\startbuffer[b]
+\definefontfeature[whatever][axis={weight:200,contrast:20}]%
+\definedfont[name:adobevariablefontprototype*whatever]bachotex%
+\stopbuffer
+
+\startbuffer[c]
+\definefontfeature[whatever][axis={weight:200,contrast:50}]%
+\definedfont[name:adobevariablefontprototype*whatever]bachotex%
+\stopbuffer
+
+\startsubject[title=Stay within specification]
+    \getbuffer[draw]
+\stopsubject
+
+\startsubject[title=Subjective choices]
+    \getbuffer[fill]
+\stopsubject
+
+\startbuffer[a]
+\definefontfeature[whatever][axis={weight:100,contrast:0}]%
+\definedfont[name:adobevariablefontprototype*whatever]tex%
+\stopbuffer
+
+\startbuffer[b]
+\definefontfeature[whatever][axis={weight:200,contrast:20}]%
+\definedfont[name:adobevariablefontprototype*whatever]tex%
+\stopbuffer
+
+\startbuffer[c]
+\definefontfeature[whatever][axis={weight:200,contrast:50}]%
+\definedfont[name:adobevariablefontprototype*whatever]tex%
+\stopbuffer
+
+\startsubject[title=Difficult choices]
+    \getbuffer[overlay]
+\stopsubject
+
+\startsubject[title=Definitions (1)]
+
+\startbuffer
+\definefontfeature
+  [default:shaped]
+  [default]
+  [axis={width:10}]
+
+\definefont
+  [SomeFont]
+  [file:avenirnextvariable*default:shaped]
+\stopbuffer
+
+\typebuffer \getbuffer
+
+\start \setupinterlinespace \showglyphs \showfontkerns \SomeFont \input zapf \wordright{Hermann Zapf}\par \stop
+
+\stopsubject
+
+\startsubject[title=Definitions (2)]
+
+\startbuffer
+\definefontfeature
+  [default:shaped]
+  [default]
+  [axis={width:100,weight=200}]
+
+\definefont
+  [SomeFont]
+  [file:avenirnextvariable*default:shaped @ 12pt]
+\stopbuffer
+
+\typebuffer \getbuffer
+
+\start \setupinterlinespace  \showglyphs \showfontkerns \SomeFont \input zapf \wordright{Hermann Zapf}\par \stop
+
+\stopsubject
+
+\startsubject[title=Transformations]
+
+\subsubject{correction:}
+
+\startformula
+    x^\prime = x
+             + s_{x1} \cdot x_1
+             + s_{x2} \cdot x_2
+             + s_{x3} \cdot x_3
+             + s_{x4} \cdot x_4
+\stopformula
+
+\startformula
+    y^\prime = y
+             + s_{y1} \cdot y_1
+             + s_{y2} \cdot y_2
+             + s_{y3} \cdot y_3
+             + s_{y4} \cdot y_4
+\stopformula
+
+\subsubject{internal cff:}
+
+\starttyping
+1 <setvstore>
+120 [10 -30 40 -60] 1 <blend> ... <operator>
+100 120 [10 -30 40 -60] [30 -10 -30 20] 2 <blend> .. <operator>
+\stoptyping
+
+\subsubject{external ttf:}
+
+\starttyping
+apply x deltas [10 -30 40 -60] to x 120
+apply y deltas [30 -10 -30 20] to y 100
+\stoptyping
+
+\stopsubject
+
+\startsubject[title=Follow up]
+
+\startitemize
+\startitem
+    Performance is quite okay because we cache instances. I might come up with an
+    alternative way but there is not much to gain.
+\stopitem
+\startitem
+    Once fonts show up alternative interfaces to axis and scaling can be explored
+    and provided.
+\stopitem
+\startitem
+    I will look into ways to do all the backend font code in \CONTEXT\ in \LUA\
+    (easier to update and more flexible).
+\stopitem
+\startitem
+    Luigi and I will play with variable fonts defined in the traditional meta tools
+    that come with \TEX.
+\stopitem
+\stopitemize
+
+\stopsubject
+
+\stopdocument