2016-10-12 17:32:00

33 files changed, 3083 insertions, 2 deletions

diff --git a/doc/context/documents/general/fonts/fonts-mkiv.pdf b/doc/context/documents/general/fonts/fonts-mkiv.pdf
index c96d8cda2..d388df3e9 100644
--- a/doc/context/documents/general/fonts/fonts-mkiv.pdf
+++ b/doc/context/documents/general/fonts/fonts-mkiv.pdf
diff --git a/doc/context/documents/general/manuals/colors-mkiv.pdf b/doc/context/documents/general/manuals/colors-mkiv.pdf
new file mode 100644
index 000000000..f211288d9
--- /dev/null
+++ b/doc/context/documents/general/manuals/colors-mkiv.pdf
diff --git a/doc/context/documents/general/manuals/columnsets.pdf b/doc/context/documents/general/manuals/columnsets.pdf
index 0d4e862f1..32a7f8b06 100644
--- a/doc/context/documents/general/manuals/columnsets.pdf
+++ b/doc/context/documents/general/manuals/columnsets.pdf
diff --git a/doc/context/documents/general/manuals/luatex.pdf b/doc/context/documents/general/manuals/luatex.pdf
index 63f06d4ba..e06e1d873 100644
--- a/doc/context/documents/general/manuals/luatex.pdf
+++ b/doc/context/documents/general/manuals/luatex.pdf
diff --git a/doc/context/documents/general/manuals/rules-mkiv.pdf b/doc/context/documents/general/manuals/rules-mkiv.pdf
index ff2155273..e3f061e24 100644
--- a/doc/context/documents/general/manuals/rules-mkiv.pdf
+++ b/doc/context/documents/general/manuals/rules-mkiv.pdf
diff --git a/doc/context/documents/general/manuals/spreadsheets-mkiv.pdf b/doc/context/documents/general/manuals/spreadsheets-mkiv.pdf
new file mode 100644
index 000000000..d8709f169
--- /dev/null
+++ b/doc/context/documents/general/manuals/spreadsheets-mkiv.pdf
diff --git a/doc/context/documents/general/manuals/steps-mkiv.pdf b/doc/context/documents/general/manuals/steps-mkiv.pdf
index fabdff6b2..f39b7be1b 100644
--- a/doc/context/documents/general/manuals/steps-mkiv.pdf
+++ b/doc/context/documents/general/manuals/steps-mkiv.pdf
diff --git a/doc/context/documents/general/manuals/workflows-mkiv.pdf b/doc/context/documents/general/manuals/workflows-mkiv.pdf
index 95a8809a8..cbbec0a5a 100644
--- a/doc/context/documents/general/manuals/workflows-mkiv.pdf
+++ b/doc/context/documents/general/manuals/workflows-mkiv.pdf
diff --git a/doc/context/documents/general/qrcs/setup-cs.pdf b/doc/context/documents/general/qrcs/setup-cs.pdf
new file mode 100644
index 000000000..164adb035
--- /dev/null
+++ b/doc/context/documents/general/qrcs/setup-cs.pdf
diff --git a/doc/context/documents/general/qrcs/setup-de.pdf b/doc/context/documents/general/qrcs/setup-de.pdf
new file mode 100644
index 000000000..41365c799
--- /dev/null
+++ b/doc/context/documents/general/qrcs/setup-de.pdf
diff --git a/doc/context/documents/general/qrcs/setup-en.pdf b/doc/context/documents/general/qrcs/setup-en.pdf
new file mode 100644
index 000000000..6caf60cc2
--- /dev/null
+++ b/doc/context/documents/general/qrcs/setup-en.pdf
diff --git a/doc/context/documents/general/qrcs/setup-fr.pdf b/doc/context/documents/general/qrcs/setup-fr.pdf
new file mode 100644
index 000000000..01acd8a5a
--- /dev/null
+++ b/doc/context/documents/general/qrcs/setup-fr.pdf
diff --git a/doc/context/documents/general/qrcs/setup-it.pdf b/doc/context/documents/general/qrcs/setup-it.pdf
new file mode 100644
index 000000000..6210c3d63
--- /dev/null
+++ b/doc/context/documents/general/qrcs/setup-it.pdf
diff --git a/doc/context/documents/general/qrcs/setup-nl.pdf b/doc/context/documents/general/qrcs/setup-nl.pdf
new file mode 100644
index 000000000..cb2f502b9
--- /dev/null
+++ b/doc/context/documents/general/qrcs/setup-nl.pdf
diff --git a/doc/context/documents/general/qrcs/setup-ro.pdf b/doc/context/documents/general/qrcs/setup-ro.pdf
new file mode 100644
index 000000000..06b79b283
--- /dev/null
+++ b/doc/context/documents/general/qrcs/setup-ro.pdf
diff --git a/doc/context/general/qrcs/setup-cs.pdf b/doc/context/general/qrcs/setup-cs.pdf
deleted file mode 100644
index 4349fe525..000000000
--- a/doc/context/general/qrcs/setup-cs.pdf
+++ /dev/null
diff --git a/doc/context/general/qrcs/setup-de.pdf b/doc/context/general/qrcs/setup-de.pdf
deleted file mode 100644
index 082e3c2c9..000000000
--- a/doc/context/general/qrcs/setup-de.pdf
+++ /dev/null
diff --git a/doc/context/general/qrcs/setup-en.pdf b/doc/context/general/qrcs/setup-en.pdf
deleted file mode 100644
index 34f77b0b3..000000000
--- a/doc/context/general/qrcs/setup-en.pdf
+++ /dev/null
diff --git a/doc/context/general/qrcs/setup-fr.pdf b/doc/context/general/qrcs/setup-fr.pdf
deleted file mode 100644
index ad1c7d8aa..000000000
--- a/doc/context/general/qrcs/setup-fr.pdf
+++ /dev/null
diff --git a/doc/context/general/qrcs/setup-it.pdf b/doc/context/general/qrcs/setup-it.pdf
deleted file mode 100644
index e0e0e71f9..000000000
--- a/doc/context/general/qrcs/setup-it.pdf
+++ /dev/null
diff --git a/doc/context/general/qrcs/setup-nl.pdf b/doc/context/general/qrcs/setup-nl.pdf
deleted file mode 100644
index cd7df2807..000000000
--- a/doc/context/general/qrcs/setup-nl.pdf
+++ /dev/null
diff --git a/doc/context/general/qrcs/setup-ro.pdf b/doc/context/general/qrcs/setup-ro.pdf
deleted file mode 100644
index 64bee894d..000000000
--- a/doc/context/general/qrcs/setup-ro.pdf
+++ /dev/null
diff --git a/doc/context/sources/general/fonts/fonts/fonts-extensions.tex b/doc/context/sources/general/fonts/fonts/fonts-extensions.tex
index 2742b1ce0..89257f1f5 100644
--- a/doc/context/sources/general/fonts/fonts/fonts-extensions.tex
+++ b/doc/context/sources/general/fonts/fonts/fonts-extensions.tex
@@ -1233,6 +1233,44 @@ command:
 
 \stopsection
 
+\startsection[title=Extra font kerns]
+
+Fonts are processed independent of each other. Sometimes that is unfortunate for
+kerning, although in practice it won't happen that often. We can enable an
+additional kerning mechanism to deal with these cases. The \type
+{\setextrafontkerns} command takes one argument between square brackets. The
+effect can be seen below:
+
+\startbuffer
+    VA {\smallcaps va} V{\smallcaps a}
+    VA {\bf VA} V{\bf A} {\bf V}A
+    V{\it A}
+\stopbuffer
+
+\starttabulate[|Tl|l|p|]
+\HL
+\BC key \BC result \BC logic \NC \NR
+\HL
+\NC no kerns \NC \showfontkerns\setextrafontkerns[reset]\subff{f:kern}\inlinebuffer \NC no kerns at all \NC \NR
+\NC kerns    \NC \showfontkerns\setextrafontkerns[reset]\inlinebuffer \NC kerns within a font (feature) run \NC \NR
+\HL
+\NC none     \NC \showfontkerns\setextrafontkerns [none]\inlinebuffer \NC only extra kerns within fonts \NC \NR
+\NC min      \NC \showfontkerns\setextrafontkerns  [min]\inlinebuffer \NC minimal kerns within and across fonts \NC \NR
+\NC max      \NC \showfontkerns\setextrafontkerns  [max]\inlinebuffer \NC maximum kerns within and across fonts \NC \NR
+\NC mixed    \NC \showfontkerns\setextrafontkerns[mixed]\inlinebuffer \NC averaged kerns within and across fonts \NC \NR
+\HL
+\stoptabulate
+
+The content is defined as:
+
+\typebuffer
+
+This mechanism obeys grouping so you have complete control over where and when
+it gets applied. The \type {\showfontkerns} command can be used to trace the
+injection of (font) kerns.
+
+\stopsection
+
 \startsection[title=Ligatures]
 
 For some Latin fonts ligature building is quite advanced, take Unifraktur. I have no
diff --git a/doc/context/sources/general/fonts/fonts/fonts-features.tex b/doc/context/sources/general/fonts/fonts/fonts-features.tex
index 79085c236..4514f209a 100644
--- a/doc/context/sources/general/fonts/fonts/fonts-features.tex
+++ b/doc/context/sources/general/fonts/fonts/fonts-features.tex
@@ -891,7 +891,7 @@ one never knows what to expect.
 
 How do we know what faces add up to the ligature {\emoji\Man \zwj \Woman \zwj
 \Girl \zwj \Boy} and how are we supposed to know that there should {\darkgray
-\type {zwj}} in between? When we input four faces seoarated by zero width
+\type {zwj}} in between? When we input four faces separated by zero width
 joiners, we get a four face symbol instead. The reason for having the joiners in
 between is probably to avoid unexpected ligatures. The sequence \type {man},
 \type {woman}, \type {boy}, \type {boy} gives \type {family}:
@@ -2531,6 +2531,49 @@ unlikely to show up in future versions of the Latin Modern fonts.
 
 \stopsection
 
+\startsection[title=Discretionaries]
+
+% speed test:
+%
+% \edef\tufte{\cldloadfile{tufte}}
+% \enabledirectives[otf.alwaysdisc]
+% \testfeatureonce{100}{\setbox0\hbox{\tufte \smallcaps \tufte}}\elapsedtime\par
+% \disabledirectives[otf.alwaysdisc]
+% \testfeatureonce{100}{\setbox0\hbox{\tufte \smallcaps \tufte}}\elapsedtime\par
+
+\startbuffer
+\definedfont[cambria*default]
+12\discretionary
+    {3} {4} {5}%
+67\par
+12{\oldstyle\discretionary
+    {3} {4} {5}}%
+67\par
+12\discretionary
+    {3{\oldstyle3}} {{\oldstyle4}4} {5{\oldstyle5}5}%
+67\par
+\stopbuffer
+
+The font handler has to do some magick to get features working with and across
+discretionaries. To some extend you can use font switches inside discretionaries
+but for sure border cases are not dealt with. This works:
+
+\startlinecorrection[blank]
+\startcombination[nx=4,ny=1,location=top]
+    {\framed[align=normal]{\enabledirectives [otf.alwaysdisc]\setupwhitespace[line]\getbuffer}} {1}
+    {\framed[align=normal]{\enabledirectives [otf.alwaysdisc]\hsize1mm\getbuffer}} {2}
+    {\framed[align=normal]{\disabledirectives[otf.alwaysdisc]\setupwhitespace[line]\getbuffer}} {3}
+    {\framed[align=normal]{\disabledirectives[otf.alwaysdisc]\hsize1mm\getbuffer}} {4}
+\stopcombination
+\stoplinecorrection
+
+The first two examples have \type {otf.alwaysdisk} enabled, the last two have it
+disabled.
+
+\typebuffer
+
+\stopsection
+
 \startsection[title=Some remarks]
 
 If you talk about features and fonts it is not difficult to end up speaking
diff --git a/doc/context/sources/general/manuals/colors/colors-basics.tex b/doc/context/sources/general/manuals/colors/colors-basics.tex
new file mode 100644
index 000000000..4d7822bd0
--- /dev/null
+++ b/doc/context/sources/general/manuals/colors/colors-basics.tex
@@ -0,0 +1,1204 @@
+% language=uk
+
+\startcomponent colors-basics
+
+\environment colors-environment
+
+\usemodule[setups-basics] \loadsetups[i-color]
+
+\startchapter[title=Basics][color=darkred]
+
+\startsection[title=Color models]
+
+When you work with displays, and most of us do, the dominant color model is \RGB.
+As far as I know \CMYK\ electrowetting displays are still not in production and
+even there the \CMYK\ seems to have made place for \RGB\ (at least in promotion
+movies). This is strange since where \RGB\ is used in cases where colors are
+radiated, \CMYK\ shows up in reflective situations (and epub readers are just
+that). But \RGB\ and \CMYK\ being complementary is not the only difference:
+\CMYK\ has an explicit black channel, and as a consequence you cannot go from one
+to the other color space without loss.
+
+In print \CMYK\ is dominant but in order to get real good colors you can go with
+spot colors. The ink is not mixed with others but applied in more or less
+quantity. A mixture of spot colors and \CMYK\ is used too. You can combine spot
+colors into a so called multitone color. Often spot colors have names (for
+instance refering to Pantone) but they always have a specification in another
+color space in order to be shown on screen. Think of \quotation {gold} being a
+valid ink, but hard to render on screen, so some yellowish replacement is used
+there when documents get prepared on screen.
+
+In \CONTEXT\ all these models are supported, either or not at the same time. In \MKII\
+you had to turn on color support explicitly, if only because of the impact of the
+overhead on performance, but in \MKIV\ color is on by default. You can disable it
+with:
+
+\starttyping
+\setupcolors
+  [state=stop]
+\stoptyping
+
+The three mentioned models are controlled by keys, and by default we have set:
+
+\starttyping
+\setupcolors
+  [rgb=yes,
+   cmyk=yes,
+   spot=yes]
+\stoptyping
+
+Spot colors and their combinations in multitone colors are controlled by the same
+parameter. You can define colors in the \HSV\ color space but in the end these
+become and behave like \RGB.
+
+\stopsection
+
+\startsection[title=Using color]
+
+Normally you will use colors grouped. Most environments accept a \type {color}
+parameter (some have \type {textcolor} or similar longer names too). In a running
+text you can use:
+
+\starttyping
+\color[red]{This will show up red.}
+\stoptyping
+
+or:
+
+\starttyping
+\startcolor[red]
+    This will show up red.
+\stopcolor
+\stoptyping
+
+In case you don't want the grouping you can use:
+
+\starttyping
+\directcolor[red]
+\stoptyping
+
+You can even use:
+
+\starttyping
+\colored[r=0.5]{also red}
+\stoptyping
+
+In which case an anonymous color is used. An ungrouped variant of this is:
+
+\starttyping
+\directcolored[r=0.5]
+\stoptyping
+
+You will seldom use these direct variants, but they might come in handy when you
+write macros yourself where extra grouping starts interfering. In fact, it often
+makes sense to use a bit more abstraction:
+
+\startbuffer
+\definehighlight
+  [important]
+  [color=red]
+
+First \highlight[important]{or} second \important {or} third.
+\stopbuffer
+
+\typebuffer
+
+This gives: \inlinebuffer .
+
+\stopsection
+
+\startsection[title=Using \CMYK\ or \RGB]
+
+When you compare colors in different color spaces, you need to be aware of the
+fact that when a black component is used in \CMYK, conversion to \RGB\ might give
+the same results but going back from that to \CMYK\ will look different from the
+original. Also, \CMYK\ colors are often tuned for specific paper.
+
+\startbuffer
+\definecolor[demo:rgb:1][r=1.0,g=1.0]
+\definecolor[demo:rgb:2][r=1.0,g=1.0,b=0.5]
+\definecolor[demo:rgb:3][r=1.0,g=1.0,b=0.6]
+\definecolor[demo:cmy:1][y=1.0]
+\definecolor[demo:cmy:2][y=0.5]
+\definecolor[demo:cmy:3][y=0.4]
+\stopbuffer
+
+\typebuffer \getbuffer
+
+In these definitions we have no black component. In \in {figure}
+[color:rgb:cmyk:1] we see how these colors translate to the other color spaces.
+
+\startbuffer[compare]
+\startbuffer
+\definemeasure[demo][(\textwidth-2em)/3]
+\startcombination[3*2]
+    {\blackrule[width=\measure{demo},height=1cm,depth=0cm,color=demo:rgb:1]}{\infofont\colorcomponents{demo:rgb:1}}
+    {\blackrule[width=\measure{demo},height=1cm,depth=0cm,color=demo:rgb:2]}{\infofont\colorcomponents{demo:rgb:2}}
+    {\blackrule[width=\measure{demo},height=1cm,depth=0cm,color=demo:rgb:3]}{\infofont\colorcomponents{demo:rgb:3}}
+    {\blackrule[width=\measure{demo},height=1cm,depth=0cm,color=demo:cmy:1]}{\infofont\colorcomponents{demo:cmy:1}}
+    {\blackrule[width=\measure{demo},height=1cm,depth=0cm,color=demo:cmy:2]}{\infofont\colorcomponents{demo:cmy:2}}
+    {\blackrule[width=\measure{demo},height=1cm,depth=0cm,color=demo:cmy:3]}{\infofont\colorcomponents{demo:cmy:3}}
+\stopcombination
+\stopbuffer
+
+\startcombination[1*4]
+    {\setupcolors[rgb=yes,cmyk=yes]\getbuffer} {Both \RGB\ and \CMYK\ enabled}
+    {\setupcolors [rgb=no,cmyk=yes]\getbuffer} {Only \CMYK\ enabled.}
+    {\setupcolors [rgb=yes,cmyk=no]\getbuffer} {Only \RGB\ enabled.}
+    {\setupcolors  [rgb=no,cmyk=no]\getbuffer} {Both \RGB\ and \CMYK\ disabled.}
+\stopcombination
+\stopbuffer
+
+\startplacefigure[location=page,reference=color:rgb:cmyk:1,title={What happens when we disable color spaces.}]
+    \getbuffer[compare]
+\stopplacefigure
+
+\startbuffer
+\definecolor[demo:rgb:1][r=0.5,g=0.6,b=0.7]
+\definecolor[demo:rgb:2][r=0.5,g=0.6,b=0.7]
+\definecolor[demo:rgb:3][r=0.5,g=0.6,b=0.7]
+\definecolor[demo:cmy:1][c=0.5,m=0.4,y=0.3]
+\definecolor[demo:cmy:2][c=0.4,m=0.3,y=0.2,k=0.1]
+\definecolor[demo:cmy:3][c=0.3,m=0.2,y=0.1,k=0.2]
+\stopbuffer
+
+\typebuffer \getbuffer
+
+When we define the colors as above, you can see a difference between the \RGB\
+and \CMYK\ values, but also between a black component versus black distributed
+over the colorants. This is seen best in \in {figure} [color:rgb:cmyk:2] when we
+compare the first and third colors alongside. In \in {figure} [color:rgb:cmyk:3]
+you see the whole repertoire.
+
+\startplacefigure[reference=color:rgb:cmyk:2,title={The impact of black on a \CMYK\ color.}]
+\startMPcode
+    fill fullsquare xyscaled (TextWidth,25mm) withcolor \MPcolor{demo:cmy:3} ;
+    fill fullsquare xyscaled (TextWidth,20mm) withcolor \MPcolor{demo:cmy:1} ;
+    fill fullsquare xyscaled (TextWidth,10mm) withcolor \MPcolor{demo:cmy:3} ;
+    fill fullsquare xyscaled (TextWidth, 5mm) withcolor \MPcolor{demo:cmy:1} ;
+\stopMPcode
+\stopplacefigure
+
+\startplacefigure[reference=color:rgb:cmyk:3,title={What happens when we disable color spaces (black component).}]
+    \getbuffer[compare]
+\stopplacefigure
+
+\stopsection
+
+\startsection[title=Conversion]
+
+A conversion to gray happens when \RGB\ and \CMYK\ are both disabled. The following
+setting forces conversion. It disables both \RGB\ and \CMYK:
+
+\starttyping
+\setupcolors
+  [conversion=always]
+\stoptyping
+
+The default setting is \type {yes} which means that colors will be reduced to gray in
+the backend. This is an optimization which can result in slightly smaller output:
+
+\starttabulate[|l|c|l|]
+\NC          \NC \bf \# \NC \bf \PDF\ sequence                  \NC \NR
+\NC \bf cmyk \NC 23     \NC \tttf 0 0 0 0.5 k 0 0 0 0.5 K       \NC \NR
+\NC \bf rgb  \NC 29     \NC \tttf 0.5 0.5 0.5 rg 0.5 0.5 0.5 RG \NC \NR
+\NC \bf gray \NC 11     \NC \tttf 0.5 g 0.5 G                   \NC \NR
+\stoptabulate
+
+The conversion to gray is controlled by:
+
+\starttyping
+\setupcolors
+  [factor=yes]
+\stoptyping
+
+Like \type {conversion} the \type {factor} is a global setting. You can play with the factor values.
+The default (\type {yes}) uses the factors used by color television:
+
+\startformula
+    s = 0.30r + 0.59g + 0.11b
+\stopformula
+
+In \in {figure} [color:demo:gray] we demonstrate what happens when you use different
+values. Normally you won't change the defaults but for experimenting we do provide
+the option:
+
+\starttyping
+\setupcolors
+  [factor=0.20:0.40:0.40]
+\stoptyping
+
+There is one pitfall. Colors are finalized per page and as this is a backend
+feature the value current when a page is shipped out is used. An exception are
+\METAPOST\ graphics, as they have local resources and are finalized immediately.
+This is hardly a limitation because one will never set these numbers in the
+middle of a document.
+
+\starttexdefinition color:demo:gray:do
+    \definecolor[demo:rgb:0][r=0.5,g=0.6,b=0.7]
+  % \blackrule[width=4cm,height=1cm,color=demo:rgb:0]
+    \lower.4\strutdp\hbox\bgroup
+        \startMPcode
+            fill unitsquare xyscaled (.5TextWidth,.9LineHeight)
+                withcolor "demo:rgb:0";
+        \stopMPcode
+    \egroup
+\stoptexdefinition
+
+\starttexdefinition color:demo:gray #1#2#3
+    \NC \tttf #1 \NC \tttf #2  \NC \tttf #3 \NC
+        \setupcolors[factor={#1:#2:#3}]
+        \setupcolors[rgb=no,cmyk=no]
+        \texdefinition{color:demo:gray:do}
+        \setupcolors[factor=yes]
+    \NC \NR
+\stoptexdefinition
+
+\startplacefigure[reference=color:demo:gray,title={Color to gray conversion using factors.}]
+\starttabulate[|c|c|c|c|]
+\NC \bf r \NC \bf g \NC \bf b \NC \bf gray \NC \NR
+\NC       \NC       \NC       \NC \texdefinition{color:demo:gray:do} \NC \NR
+\texdefinition{color:demo:gray}{0.30}{0.59}{0.11}
+\texdefinition{color:demo:gray}{0.30}{0.11}{0.59}
+\texdefinition{color:demo:gray}{0.59}{0.30}{0.11}
+\texdefinition{color:demo:gray}{0.11}{0.30}{0.59}
+\texdefinition{color:demo:gray}{0.11}{0.59}{0.30}
+\texdefinition{color:demo:gray}{0.59}{0.11}{0.30}
+\texdefinition{color:demo:gray}{0.20}{0.40}{0.40}
+\texdefinition{color:demo:gray}{0.30}{0.60}{0.10}
+\texdefinition{color:demo:gray}{0.20}{0.30}{0.20}
+\texdefinition{color:demo:gray}{0.40}{0.40}{0.40}
+\stoptabulate
+\stopplacefigure
+
+\stopsection
+
+% let's take a break and watch: https://www.youtube.com/watch?v=baLrrW3El-M
+
+\startsection[title=Definitions]
+
+The mostly used color definition command is \type {\definecolor}. Here we define the
+primary colors:
+
+\startbuffer
+\definecolor [red]     [r=1]
+\definecolor [green]   [g=1]
+\definecolor [blue]    [b=1]
+\definecolor [yellow]  [y=1]
+\definecolor [magenta] [m=1]
+\definecolor [cyan]    [c=1]
+\stopbuffer
+
+\typebuffer \getbuffer
+
+These can be visualized as follows:
+
+\startbuffer
+\showcolorcomponents[red,green,blue,yellow,magenta,cyan,black]
+\stopbuffer
+
+\typebuffer \getbuffer
+
+Transparency is included in these tables but is, as already noted, in fact
+independent. It can be defined with a color:
+
+\startbuffer
+\definecolor [t:red]   [r=1,a=1,t=.5]
+\definecolor [t:green] [g=1,a=1,t=.5]
+\definecolor [t:blue]  [b=1,a=1,t=.5]
+\stopbuffer
+
+\typebuffer \getbuffer
+
+This time the transparency values show up too:
+
+\showcolorcomponents[t:red,t:green,t:blue]
+
+Because transparency is separated from color, we can define transparent behaviour
+as follows:
+
+\startbuffer
+\definecolor[t:only] [a=1,t=.5]
+\stopbuffer
+
+\typebuffer \getbuffer
+
+\startbuffer
+    \dontleavehmode
+    \blackrule[width=4cm,height=1cm,color=darkgreen]%
+    \hskip-2cm
+    \color[t:only]{\blackrule[width=4cm,height=1cm,color=darkred]}%
+    \hskip-2cm
+    \color[t:only]{\blackrule[width=4cm,height=1cm]}
+\stopbuffer
+
+\typebuffer
+
+We skip back to create an overlay, so we get:
+
+\startlinecorrection
+\getbuffer
+\stoplinecorrection
+
+In the section about transparency a bit more will be said about the relation between
+color and transparencies and how to cheat.
+
+As soon as you need to typeset something for professional printing, spot colors
+will show up so they are supported too. A spot color is not really a color but
+related to the substance that gets put on the paper. This can be ink but also
+something metallic, like silver, gold or some texture. In these cases we need
+something to represent it when not printed on a suitable device so again we end
+up with a color. This is reflected in the way spot colors are set up.
+
+\startbuffer
+\definecolor     [parentspot]               [r=.5,g=.2,b=.8]
+\definespotcolor [childspot-1] [parentspot] [p=.7,e=fancy]
+\definespotcolor [childspot-2] [parentspot] [p=.4]
+\stopbuffer
+
+\typebuffer \getbuffer
+
+The three colors, two of them are spot colors, show up as follows:
+
+\setupcolors[spot=yes]
+
+\showcolorcomponents[parentspot,childspot-1,childspot-2]
+
+The \type {p} is comparable to the \type {s} in gray scales. The \type {e}
+parameter can be used to specify a name for the color. In the \PDF\ file that
+name will become the separation name (a popular commercial naming scheme is
+Pantone).
+
+A combination of spotcolor is called a multitone color. These are defined as
+follows (we also define a few spotcolors and use transparency):
+
+\startbuffer
+\definespotcolor [spotone]   [darkred]   [p=1]
+\definespotcolor [spottwo]   [darkgreen] [p=1]
+
+\definespotcolor [spotone-t] [darkred]   [a=1,t=.5]
+\definespotcolor [spottwo-t] [darkgreen] [a=1,t=.5]
+
+\definemultitonecolor
+    [whatever]
+    [spotone=.5,spottwo=.5]
+    [b=.5]
+
+\definemultitonecolor
+    [whatever-t]
+    [spotone=.5,spottwo=.5]
+    [b=.5]
+    [a=1,t=.5]
+\stopbuffer
+
+\typebuffer \getbuffer
+
+\showcolorcomponents[spotone,spottwo,spotone-t,spottwo-t,whatever,whatever-t]
+
+Transparencies combine as follows:
+
+\startbuffer
+\blackrule[width=3cm,height=1cm,color=spotone-t]\hskip-1.5cm
+\blackrule[width=3cm,height=1cm,color=spotone-t]
+\stopbuffer
+
+\typebuffer
+
+\startlinecorrection
+\dontleavehmode\getbuffer
+\stoplinecorrection
+
+In case you want to specify colors in the \HSV\ color space, you can do that too.
+The hue parameter (\type {h}) is in degrees and runs from 0 upto 360 (larger
+values get divided). The saturation (\type {s}) and value (\type {v}) parameters
+run from 0 to 1. The \type {v} parameter is mandate. In \in {figure} [fig:hsv] we
+show what the last two variables do.
+
+\starttyping
+\definecolor[somecolor][h=125,s=0.5,v=0.8]
+\stoptyping
+
+\startMPextensions
+    vardef hsvcircle(expr s, v) =
+        image ( save p ; path p ; p := fullcircle ;
+            save l ; numeric l ; l := length(p)/360 ;
+            for i=0 upto 360 :
+                fill origin -- subpath (i*l,(i+1)*l) of p -- cycle withcolor hsvtorgb(i,s,v) ;
+            endfor ;
+        )
+    enddef;
+\stopMPextensions
+
+\startplacefigure[reference=fig:hsv,title={Four hsv color circle running from 0 to 360 degrees, with zero at the right.}]
+    \startcombination[4*1]
+        {\startMPcode draw hsvcircle(0.6,0.6) scaled 3cm ; \stopMPcode} {\tttf s=0.6 v=0.6}
+        {\startMPcode draw hsvcircle(0.4,0.6) scaled 3cm ; \stopMPcode} {\tttf s=0.4 v=0.6}
+        {\startMPcode draw hsvcircle(0.6,0.4) scaled 3cm ; \stopMPcode} {\tttf s=0.6 v=0.4}
+        {\startMPcode draw hsvcircle(0.4,0.4) scaled 3cm ; \stopMPcode} {\tttf s=0.4 v=0.4}
+    \stopcombination
+\stopplacefigure
+
+% \scratchdimen\dimexpr(\textwidth-118pt)/120\relax
+% \dontleavehmode \dostepwiserecurse{0}{359}{1}{%
+%     \definecolor[tempcolor][h=#1,s=0.6,v=0.6]%
+%     \blackrule[color=tempcolor,width=\scratchdimen,height=1ex,depth=1ex]%
+%     \hskip1pt
+% }
+
+If you need to use hexadecimal color specifications you can use these
+definitions:
+
+\starttyping
+\definecolor[mycolor][x=4477AA]
+\definecolor[mycolor][h=4477AA]
+\definecolor[mycolor][x=66]
+\definecolor[mycolor][#4477AA]
+\stoptyping
+
+The \type {#} is normally not accepted in \TEX\ source code but when you get the
+specification from elsewhere (e.g.\ \XML) it can be convenient.
+
+\stopsection
+
+\startsection[title=Freezing colors]
+
+We can clone colors and thereby overload color dynamically. You can however
+freeze colors via the setup option \type {expansion}.
+
+\startbuffer
+\definecolor[green]   [r=.5]{({\green green ->   red})}
+\definecolor[green]   [g=.5]{({\green green -> green})}
+\definecolor[green]   [blue]{({\green green ->  blue})}
+\definecolor[blue]     [red]{({\green green ->   red})}
+\setupcolors[expansion=yes]%
+\definecolor[blue]     [red]%
+\definecolor[green]   [blue]%
+\definecolor[blue]    [r=.5]{({\green green ->  blue})}
+\stopbuffer
+
+\typebuffer
+
+\start
+\definecolor[red]  [r=.5]%
+\definecolor[green][g=.5]%
+\definecolor[blue] [b=.5]%
+\getbuffer
+\stop
+
+\stopsection
+
+\startsection[title=Color groups]
+
+Nowadays we seldom use colorgroups but they are still supported. Groups are
+collections of distinctive colors, something we needed in projects where many
+graphics had to be made and consistency between text and image colors was
+important. The groups can be translated into similar collections in drawing
+programs used at that time.
+
+\startbuffer
+\definecolorgroup
+  [redish]
+  [1.00:0.90:0.90, % 1
+   1.00:0.80:0.80, % 2
+   1.00:0.70:0.70, % 3
+   1.00:0.55:0.55, % 4
+   1.00:0.40:0.40, % 5
+   1.00:0.25:0.25, % 6
+   1.00:0.15:0.15, % 7
+   0.90:0.00:0.00] % 8
+\stopbuffer
+
+\typebuffer \getbuffer
+
+The redish color is called by number:
+
+\startbuffer
+\blackrule[width=3cm,height=1cm,depth=0pt,color=redish:1]\quad
+\blackrule[width=3cm,height=1cm,depth=0pt,color=redish:2]\quad
+\blackrule[width=3cm,height=1cm,depth=0pt,color=redish:3]
+\stopbuffer
+
+\typebuffer
+
+The number of elements is normally limited and eight is about what is useful and
+still distinguishes good enough when printed in black and white.
+
+\startlinecorrection
+\dontleavehmode\getbuffer
+\stoplinecorrection
+
+\startlinecorrection
+\setupcolors[rgb=no,cmyk=no]\dontleavehmode\getbuffer
+\stoplinecorrection
+
+\stopsection
+
+\startsection[title=Palets]
+
+Color palets are handy when you want to use a set of (named) colors but
+also want to switch efficiently between different definitions:
+
+\startbuffer
+\definepalet
+  [standard]
+  [darkred=darkcyan,
+   darkgreen=darkmagenta,
+   darkblue=darkyellow]
+\stopbuffer
+
+\typebuffer \getbuffer
+
+The \type {\setuppalet} commands switches to a palet. When a requested color is
+not part of a palet, a regular lookup happens. This is used as:
+
+\startbuffer
+\blackrule[width=15mm,height=10mm,depth=0mm,color=darkred]\quad
+\blackrule[width=15mm,height=10mm,depth=0mm,color=darkgreen]\quad
+\blackrule[width=15mm,height=10mm,depth=0mm,color=darkblue]\quad
+\setuppalet[standard]%
+\blackrule[width=15mm,height=10mm,depth=0mm,color=darkred]\quad
+\blackrule[width=15mm,height=10mm,depth=0mm,color=darkgreen]\quad
+\blackrule[width=15mm,height=10mm,depth=0mm,color=darkblue]
+\stopbuffer
+
+\typebuffer
+
+\startlinecorrection
+\dontleavehmode \getbuffer
+\stoplinecorrection
+
+Here we use color names but often you end up with more symbolic names:
+
+\starttyping
+\definepalet
+  [standard]
+  [important=darkred,
+   notabene=darkgreen,
+   warning=darkyellow]
+\stoptyping
+
+As with the regular color commands, the palet mechanism is an old one but it is
+well integrated. Instead of inheriting you can also use definitions:
+
+\starttyping
+\definepalet
+  [standard]
+  [important={r=.5},
+   notabene={g=.5},
+   warning={r=.5,g=.5}]
+\stoptyping
+
+\stopsection
+
+\startsection[title=Transparency]
+
+We already discussed transparency as part of colors. In most cases we will choose
+type {normal} (or \type {1}) as transparency type, but there are more:
+
+\startluacode
+    local codes = table.swapped(attributes.transparencies.names)
+
+    context.startcolumns { n = 4 }
+    context.starttabulate ( { "|B||" }, { keeptogether = "no" } )
+    for i=0,#codes do
+        context.NC()
+        context(i)
+        context.NC()
+        context(codes[i])
+        context.NC()
+        context.NR()
+    end
+    context.stoptabulate()
+    context.stopcolumns()
+\stopluacode
+
+In \in {figure} [fig:transparency] we compare these variants. Not all are as
+effective as their effect depends on several factors. You can read more about it
+in the \PDF\ specification.
+
+\startMPextensions
+    vardef transdemo(expr b)  =
+        image ( save p ; path p ; p := fullcircle ;
+            save l ; numeric l ; l := length(p)/16 ;
+            if (b = 1) or (b = 3) :
+                fill fullcircle scaled 1.00 withcolor yellow ;
+                fill fullcircle scaled 0.80 withcolor red ;
+                fill fullcircle scaled 0.60 withcolor black ;
+                fill fullcircle scaled 0.40 withcolor white ;
+                fill fullcircle scaled 0.20 withcolor .5white ;
+            fi ;
+            if (b = 2) or (b = 3) :
+                for i=0 upto 15 :
+                    fill origin -- subpath (i*l,(i+1)*l) of p -- cycle
+                        withcolor red
+                        withtransparency (i,0.5) ;
+                    draw textext("\ttbf " & decimal i) ysized .04 shifted (.45,0) rotated (i*360/16 + 360/32) ;
+                endfor ;
+            fi ;
+        )
+    enddef;
+\stopMPextensions
+
+\startplacefigure[reference=fig:transparency,title={The differences between the transparency options. The center is explicitly filled with white.}]
+    \startcombination[3*1]
+        {\startMPcode draw transdemo(1) scaled 4cm ; \stopMPcode} {\tttf backgrounds used}
+        {\startMPcode draw transdemo(2) scaled 4cm ; \stopMPcode} {\tttf transparencies used}
+        {\startMPcode draw transdemo(3) scaled 4cm ; \stopMPcode} {\tttf transparency overlayed}
+    \stopcombination
+\stopplacefigure
+
+Colors and transparencies are coupled by definitions. We will explain this by
+some examples. When we say:
+
+\startbuffer
+\definecolor[clr1][r=.5]
+\stopbuffer
+
+\typebuffer \getbuffer
+
+A non|-|transparent color is defined and when we say:
+
+\startbuffer
+\definecolor[clr2][g=.5,a=1,t=.5]
+\stopbuffer
+
+\typebuffer \getbuffer
+
+We defined a color with a transparency. However, color and transparency get separated
+attributes. So when we nest them as in:
+
+\startbuffer
+\color[clr1]{\bf RED   \color[clr2] {GREEN}}
+\color[clr2]{\bf GREEN \color[clr1] {RED}  }
+\stopbuffer
+
+\typebuffer
+
+we get:
+
+\startlines \getbuffer \stoplines
+
+The transparency of the outer color is also applied to the inner color. If you
+don't want that, you explicitly need to set them:
+
+\startbuffer
+\definecolor[clr3][b=.5,a=1,t=1]
+\stopbuffer
+
+\typebuffer \getbuffer
+
+\startbuffer
+\color[clr1]{\bf RED   \color[clr2] {GREEN} \color[clr3]{BLUE} }
+\color[clr2]{\bf GREEN \color[clr1] {RED}   \color[clr2]{GREEN}}
+\color[clr3]{\bf BLUE  \color[clr1] {RED}   \color[clr2]{GREEN}}
+\stopbuffer
+
+\typebuffer
+
+we get:
+
+\startlines \getbuffer \stoplines
+
+If you define a transparent|-|only color, you get transparent black:
+
+\startbuffer
+\definecolor[clr4][a=1,t=.5]
+\stopbuffer
+
+\typebuffer \getbuffer
+
+So:
+
+\startbuffer
+\color[clr1]{\bf RED    \color[clr4] {RED}}
+\color[clr4]{\bf BLACK  \color[clr1] {RED}}
+\stopbuffer
+
+\typebuffer
+
+gives:
+
+\startlines \getbuffer \stoplines
+
+In addition to the already discussed definers and setters we also have a few
+special ones. Personally I never needed them but they are the for completeness.
+
+\startbuffer
+\definetransparency[tsp1][a=1,t=.5]
+\stopbuffer
+
+\typebuffer \getbuffer
+
+We apply this to some text:
+
+\startbuffer
+\color      [clr1]{\bf RED   \transparent[tsp1] {RED}   }
+\transparent[tsp1]{\bf BLACK \color      [clr1] {RED}   }
+\transparent[tsp1]{\bf BLACK \transparent[reset]{BLACK} }
+\stopbuffer
+
+\typebuffer
+
+and get:
+
+\startlines \getbuffer \stoplines
+
+We can also only switch color:
+
+\startbuffer
+\color[clr1]{\bf RED \color    [clr2] {GREEN}}
+\color[clr1]{\bf RED \coloronly[clr2] {GREEN}}
+\stopbuffer
+
+\typebuffer
+
+So the second line has no transparency:
+
+\startlines \getbuffer \stoplines
+
+The \typ {\starttransparent} and \type {\startcoloronly} commands are the
+complements of \typ {\transparent} and \typ {\coloronly}.
+
+\stopsection
+
+\startsection[title=Interpolation]
+
+You can define intermediate colors in a way comparable with \METAPOST\ \type
+{.5[red,green]} kind of specifications. Here are some examples:
+
+\startbuffer
+\definecolor [mycolor1] [.5(red,green)]
+\definecolor [mycolor2] [.8(red,green)]
+\definecolor [mycolor3] [.4(red,white)]
+\definecolor [mycolor4] [.4(white,red)]
+
+\showcolorcomponents[red,green,mycolor1,mycolor2,mycolor3,mycolor4]
+\stopbuffer
+
+\typebuffer \getbuffer
+
+An older method, still available is:
+
+\starttyping
+\defineintermediatecolor[mycolor5][0.5,red,green]
+\stoptyping
+
+A variation on this are complementary colors:
+
+\startbuffer
+\definecolor[mycolor1][.5(blue,red)]
+\definecolor[mycolor2][-.5(blue,red)]
+\definecolor[mycolor3][-(blue)]
+\definecolor[mycolor4][-(red)]
+
+\showcolorcomponents[blue,red,mycolor1,mycolor2,mycolor3,mycolor4]
+\stopbuffer
+
+\typebuffer \getbuffer
+
+\stopsection
+
+\startsection[title=PDF]
+
+Although it is not perfect, \PDF\ evolved in such a way that it will stay around
+for a while. One reason is that it has become a standard, or more precisely a set
+of standards. Depending on what variant you choose color support is limited.
+
+\startluacode
+
+local function state(v)
+    context.NC()
+    if v then
+        context("\\star")
+    end
+end
+
+context.starttabulate { "|l|c|c|c|c|c|" }
+context.NC() context.bold("format")
+context.NC() context.bold("gray")
+context.NC() context.bold("rgb")
+context.NC() context.bold("cmyk")
+context.NC() context.bold("spot")
+-------.NC() context.bold("multi")
+context.NC() context.bold("transparency")
+context.NC() context.NR()
+for name, data in table.sortedhash(lpdf.formats.data) do
+    context.NC() context.type(name)
+    state(data.gray_scale)
+    state(data.rgb_colors)
+    state(data.cmyk_colors)
+    state(data.spot_colors)
+ -- state(data.nchannel_colorspace)
+ -- state(data.calibrated_rgb_colors)
+ -- state(data.cielab_colors)
+    state(data.transparency)
+ -- state(data.include_intents)
+ -- state(data.internal_icc_profiles)
+ -- state(data.external_icc_profiles)
+    context.NR()
+end
+context.stoptabulate()
+
+\stopluacode
+
+When you have set the \type{format} with \type {\setupbackend} to one of the
+known formats mentioned in the previous table, the color conversions will
+automatically kick in.
+
+\stopsection
+
+\startsection[title=Unboxing]
+
+This paragraph is somewhat complex, so skip it when you don't feel comfortable
+with the subject or when you've never seen low level \CONTEXT\ code.
+
+Colors are implemented using attributes. Attributes behave like fonts. This means
+that they are kind of frozen once material is boxed. Consider that we define a
+box as follows:
+
+\startbuffer
+\setbox0\hbox{\bf default {\darkred red \darkgreen green} default}
+\stopbuffer
+
+\typebuffer \getbuffer
+
+What do you expect to come out the next code? In \MKII\ the \quote {default}
+inside the box will be colored yellow but the internal red and and green words
+will keep their color.
+
+\startbuffer
+\bf default {\darkyellow yellow {\box0} yellow} default
+\stopbuffer
+
+\typebuffer
+
+This is what we get in \MKIV: \start \inlinebuffer \stop
+
+When we use fonts switches we don't expect the content of the
+box to change. So, in the following the \quote {default} texts will
+{\em not} become bold.
+
+\startbuffer
+\setbox0\hbox{default {\sl slanted \bi bold italic} default}
+\stopbuffer
+
+\typebuffer \getbuffer
+
+\startbuffer
+default {\bf bold {\box0} bold} default
+\stopbuffer
+
+\typebuffer
+
+Now we get: \inlinebuffer .
+
+Redoing a box with a new font is sort of tricky as by then all kind of
+manipulations have been applied and the original inputs is long gone. But colors
+are easier to deal with and therefore in \MKIV\ we have a trick to make sure the
+outer color gets applied to the box:
+
+\startbuffer[enable]
+\enabledirectives
+  [attributes.inheritance]
+\stopbuffer
+
+\startbuffer
+default {\bf \darkyellow yellow {\attributedbox0} yellow} default
+\stopbuffer
+
+\typebuffer
+
+So, we get: \start\inlinebuffer[box]\inlinebuffer[enable]\space\inlinebuffer
+\stop, but only after we have enabled this mechanisms explicitly:
+
+\typebuffer[enable]
+
+There is also an \type {\attributedcopy} macro. These macros signal the attribute
+resolver that this box is to be treated special.
+
+In \MKII\ we have a similar situation which is why we had the option (only used
+deep down in \CONTEXT) to encapsulate a bunch of code with
+
+\starttyping
+\startregistercolor[foregroundcolor]
+some macro code ... here foregroundcolor is applied ... more code
+\stopregistercolor
+\stoptyping
+
+This is for instance used in the \type {\framed} macro. First we package the
+content, foregroundcolor is not yet applied because the injected specials of
+literals can interfere badly, but by registering the colors the nested color
+calls are tricked into thinking that preceding and following content is colored.
+When packaged, we apply backgrounds, frames, and foregroundcolor to the whole
+result. Because nested colors were aware of the foregroundcolor they have
+properly reverted to this color when needed.
+
+In \MKIV\ the situation is reversed. Here we definitely need to set the
+foregroundcolor because otherwise attributes are not set. This is no problem
+because contrary to \MKII\ colors don't interfere (no extra nodes). We could have
+flushed the framed content using \type {\attributedbox}, but we don't want to
+enable inheritance by default because it comes with some overhead.
+
+\stopsection
+
+\startsection[title=Color intents]
+
+If we do this:
+
+\startbuffer
+\startoverlay
+    {\blackrule[color=darkred, height=2cm,width=4cm]}
+    {\blackrule[color=darkblue,height=1cm,width=3cm]}
+\stopoverlay
+\stopbuffer
+
+\typebuffer
+
+we get:
+
+\startlinecorrection
+\getbuffer
+\stoplinecorrection
+
+The blue rectangle is drawn on top of the red one. In print, normally the
+printing engine will make sure that there is no red below the blue. In case of
+transparent colors this is somewhat tricky because then we definitely want to see
+part of what lays below.
+
+You can control this process with the following commands:
+
+\starttyping
+\setupcolors
+  [intent=...]
+\stoptyping
+
+The default setting is \type {none} but you can set the intent to \type {overprint} or
+\type {knockout} as well. In a running text you can use the following commands:
+
+\starttyping
+\startcolorintent[overprint|knockout]
+    ...
+\stopcolorintent
+
+\startoverprint
+    ...
+\stopoverprint
+
+\startknockout
+    ...
+\stopknockout
+\stoptyping
+
+In practice you will probably seldom need to deal with this so best leave the defaults
+as they are.
+
+\stopsection
+
+\startsection[title=Collections]
+
+Collections are predefined sets of colors. You find them in the files \type
+{colo-imp-*.mkiv} and you can make such files yourself. When you define a color a
+command is generated by default. When you load a collection, there is a danger
+that you redefine commands unintended. For that reason most collections are
+wrapped in:
+
+\starttyping
+\startprotectedcolors
+    % definitions
+\stopprotectedcolors
+\stoptyping
+
+This prevents commands being defined and assumes that colors are accessed by
+using the \type {color} parameter of setup commands or in the text with:
+
+\starttyping
+\color[somecolor]{this gets colored}
+
+\startcolor[somecolor]
+    this gets colored
+\stopcolorintent
+\stoptyping
+
+The default set (\type {rgb}) is already preloaded with:
+
+\starttyping
+\usecolors[rgb] % preloaded
+\stoptyping
+
+You can get a list of colors with
+
+\startbuffer
+\showcolor[rgb]
+\stopbuffer
+
+\typebuffer
+
+This generates the list:
+
+\getbuffer
+
+These are the collections shipped with \CONTEXT. Some names are
+
+\starttabulate[|T||]
+\NC crayola \NC crayon colors \NC \NR
+\NC dem     \NC a demo set of groups and palets \NC \NR
+\NC ema     \NC an old coming from an Emacs user \NC \NR
+%NC pan     \NC a bunch of Pantone colors \NC \NR % can't be distributed
+%NC pra     \NC colors used at \PRAGMA \NC \NR
+\NC rainbow \NC a series of color groups by Alan \NC \NR
+\NC ral     \NC a set often used in industry (from Germany) \NC \NR
+\NC rgb     \NC a basic set of colors defined in the \RGB\ color space \NC \NR
+%NC ros     \NC the roscolux color set used in theater and cinema lighting \NC \NR % probably can't be distributed
+\NC x11     \NC (most of the) standard X11 \RGB\ colors \NC \NR
+\stoptabulate
+
+You can look in these files to see what gets defined. Even if you don't use them
+they might be illustrative,
+
+\stopsection
+
+\startsection[title=Text color]
+
+Setting the color of the running text is done with:
+
+\starttyping
+\setupcolors
+  [textcolor=darkgray]
+\stoptyping
+
+If needed you can also set the \type {pagecolormodel} there but its default value
+is \type {none} which means that it will obey the global settings.
+
+\stopsection
+
+\startsection[title=Tikz]
+
+In case you use the TikZ graphical subsystem you need to be aware of the the fact
+that its color support is more geared towards \LATEX. There is glue code that
+binds the \CONTEXT\ color system to its internal representation but there can
+still be problems. For instance, not all color systems are supported so \CONTEXT\
+will try to remap, but only when it knows that it has to do so. You can best not
+mix colorspaces when you use TikZ. If you really want (and there is no real
+reason to do so) you can say:
+
+\starttyping
+\enabledirectives[colors.pgf]
+\stoptyping
+
+and then (at the cost of some extra overhead) define colors as:
+
+\starttyping
+\definecolor[pgfcolora][blue!50!green]
+\definecolor[pgfcolorb][red!50!blue]
+\stoptyping
+
+\stopsection
+
+\startsection[title=Implementation details]
+
+The low level implementation of colors in \MKIV\ is fundamentally different from
+\MKII. In \MKIV\ something like this happens:
+
+\starttyping
+one \color[red]{two} three
+\stoptyping
+
+becomes (with grouping):
+
+\starttyping
+one {<start color: red>two<stop color>} three
+\stoptyping
+
+the start and stop points are in fact injections in the input: a special (for
+\DVI) or literals (for \PDF) is inserted that turns the color on and off, but
+also information is carried along about the state of color, so that we can
+properly nest as well as pick up the current color after a page break. We never
+had real problems with this mechanism but one had to keep in mind that injections
+like this could interfere with typesetting. This mechanism didn't rely on the
+engine for housekeeping, all was done at the \TEX\ end using so called marks.
+
+In \MKIV\ we use attributes. This means that the sequence now looks like:
+
+\starttyping
+one {<set color attribute to red>two} three
+\stoptyping
+
+The actual handling of color happens when a page is shipped out and there is no
+interference with typesetting. The work is mostly done in \LUA.
+
+Colorspaces (\RGB, \CMYK, spot) were already supported in \MKII\ and of course
+still are in \MKIV. However, the colorspace is now a more independent property.
+At some point in \MKII\ we also implemented transparency as a property of a
+color. In \MKIV\ transparency is still defined with a color but handled
+independently. This means that where in \MKII\ color is just one axis, in \MKIV\
+we have three: colorspace (model), color and transparency. This of course has a
+bit of a performance and memory hit, but in practice a user won't notice it.
+
+\stopsection
+
+\startsection[title=Grouping]
+
+The \type {\color} and \type {\startcolor} command group their arguments. There might
+be cases where this interferes with your intentions, for instance when you want to
+set some variable and use its value later on.
+
+\startbuffer
+1 \scratchcounter=1
+plus
+1 \advance \scratchcounter by 1
+equals
+\the\scratchcounter
+\stopbuffer
+
+\typebuffer
+
+The summation works out okay: {\bf \inlinebuffer}.
+
+\startbuffer
+\color[darkblue]{1 \scratchcounter=1}
+plus
+\color[darkblue]{1 \advance \scratchcounter by 1}
+equals
+\color[darkgreen]{\the\scratchcounter}
+\stopbuffer
+
+\typebuffer
+
+Here the final result depends on the value of \type {\scratchcounter}:
+{\scratchcounter 3 \bf \inlinebuffer}.
+
+\startbuffer
+\start
+    \pushcolor[darkblue]1 \scratchcounter=1 \popcolor
+    plus
+    \pushcolor[darkblue]1 \advance \scratchcounter by 1 \popcolor
+    equals
+    \pushcolor[darkgreen]\the\scratchcounter \popcolor
+\stop
+\stopbuffer
+
+\typebuffer
+
+Here we get: {\bf \inlinebuffer}. The \typ {\pushcolor} and \typ {\popcolor}
+commands can be used nested which give a bot of overhead. The \typ {\savecolor}
+and \typ {\restorecolor} commands are variants that don't stack. They are a bit
+more efficient but if you use them nested you probably also will use some
+grouping. Where the push||pop pair needs to be matched, the save||restore pair
+doesn't impose that restriction.
+
+\stopsection
+
+\startsection[title=Commands]
+
+There are quite some commands that relate to colors but you probably only need
+\typ {\definecolor}, \type {\color} and \typ {\startcolor} \unknown \typ
+{\stopcolor}. Here we show the complete list. Some commands are redundant, for
+instance \typ {\definenamedcolor} is the same as \typ {\definecolor}.
+
+\placeallsetups
+
+\stopsection
+
+\stopchapter
+
+\stopcomponent
diff --git a/doc/context/sources/general/manuals/colors/colors-environment.tex b/doc/context/sources/general/manuals/colors/colors-environment.tex
new file mode 100644
index 000000000..99f625854
--- /dev/null
+++ b/doc/context/sources/general/manuals/colors/colors-environment.tex
@@ -0,0 +1,7 @@
+\startenvironment colors-environment
+
+    \environment manuals-explaining-environment
+    \environment manuals-explaining-cover
+
+\stopenvironment
+
diff --git a/doc/context/sources/general/manuals/colors/colors-graphics.tex b/doc/context/sources/general/manuals/colors/colors-graphics.tex
new file mode 100644
index 000000000..4c8fb5270
--- /dev/null
+++ b/doc/context/sources/general/manuals/colors/colors-graphics.tex
@@ -0,0 +1,234 @@
+% language=uk
+
+\startcomponent colors-basics
+
+\environment colors-environment
+
+\startchapter[title=Graphics][color=darkblue]
+
+\startsection[title=Conversion]
+
+There is not that much to tell about graphics and color simply because from the
+perspective of \TEX\ a graphic is just a blob with dimensions that travels
+through the system and in the backend gets included as|-|is. This means that when
+there is a problem with an image you have to go back to the source of that image
+and fix it there.
+
+It can happen that you need to manipulate an image and in a fully automated
+workflow that can be cumbersome. For that reason \CONTEXT\ has a mechanism for
+converting graphics.
+
+\startluacode
+    context.starttabulate { "|BT|T|" }
+    context.NC() context.bold("original")
+    context.NC() context.bold("target")
+    context.NC() context.NR()
+    for k, v in table.sortedhash(figures.converters) do
+        context.NC() context(k)
+        context.NC() context("%{\\quad }t",table.sortedkeys(v))
+        context.NC() context.NR()
+    end
+    context.stoptabulate()
+\stopluacode
+
+Some of these converters are applied automatically. For instance if you include
+an \type {eps} image, \CONTEXT\ will try to convert it into a \PDF\ file and only
+do that once (unless the image changed). Of course it needs a conversion program,
+but as long as you have GhostScript, GraphicMagick and InkScape on your machine
+it should work out well.
+
+You can also define your own converters (we use a verbose variant):
+
+\starttyping
+\startluacode
+    -- of course we need options
+
+    local resolutions = {
+        [interfaces.variables.low]    = "150x150",
+        [interfaces.variables.medium] = "300x300",
+        [interfaces.variables.high]   = "600x600",
+    }
+
+    figures.programs.lowrespng = {
+        command  = "gm",
+        argument = [[convert -resample %resolution% "%oldname%" "%newname%"]],
+    }
+
+    figures.converters["png"]["lowres.png"] = function(oldname,newname,resolution)
+        runprogram (
+            figures.programs.lowrespng.command,
+            figures.programs.lowrespng.argument,
+            {
+                oldname    = oldname,
+                newname    = newname,
+                resolution = resolutions[resolution] or "150x150"
+            }
+        )
+    end
+\stopluacode
+\stoptyping
+
+Usage is as follows:
+
+\starttyping
+\externalfigure[mill.png][conversion=lowres.png]
+\stoptyping
+
+\stopsection
+
+\startsection[title=Recoloring]
+
+You can think of more complex conversions, like converting a gray scale image to
+a colored one.
+
+\startbuffer
+\startluacode
+    figures.programs.recolor = {
+        command  = "gm",
+        argument = [[convert -recolor "%color%" "%oldname%" "%newname%"]],
+    }
+
+    figures.converters["png"]["recolor.png"] =
+        function(oldname,newname,resolution,arguments)
+            figures.programs.run (
+                figures.programs.recolor.command,
+                figures.programs.recolor.argument,
+                {
+                    oldname = oldname,
+                    newname = newname,
+                    color   = arguments or ".5 0 0 .7 0 0 .9 0 0",
+                }
+            )
+        end
+\stopluacode
+\stopbuffer
+
+\typebuffer % built in so no \getbuffer
+
+\startbuffer
+\useexternalfigure[mill][mill.png][conversion=recolor.png]
+\startcombination[3*2]
+  {\externalfigure[mill][arguments=.5 0 0 .7 0 0 .9 0 0]}{\figurefilearguments}
+  {\externalfigure[mill][arguments=.7 0 0 .9 0 0 .5 0 0]}{\figurefilearguments}
+  {\externalfigure[mill][arguments=.9 0 0 .5 0 0 .7 0 0]}{\figurefilearguments}
+  {\externalfigure[mill][arguments=.5 0 0 .9 0 0 .7 0 0]}{\figurefilearguments}
+  {\externalfigure[mill][arguments=.7 0 0 .5 0 0 .9 0 0]}{\figurefilearguments}
+  {\externalfigure[mill][arguments=.9 0 0 .7 0 0 .5 0 0]}{\figurefilearguments}
+\stopcombination
+\stopbuffer
+
+This can be applied as follows. The \type {resolution} and \type {color}
+parameters get passed to the converter. This method is actually built
+in already.
+
+\typebuffer
+
+The results are shown in \in {figure} [fig:recolor]. In this case we pass the
+colors to be use in a kind of matrix notation that GraphicMagick needs.
+
+\startplacefigure[reference=fig:recolor,title={Recoloring bitmap images.}]
+    \getbuffer
+\stopplacefigure
+
+Recoloring an image this way is actually not the best solution because
+there is an internal mechanism that does the same. This trick (currently)
+only works with spot colors.
+
+\startbuffer
+\definecolor [my-blue]   [c=1,m=.38,y=0,k=.64] % pms 2965 uncoated m
+\definecolor [my-yellow] [c=0,m=.28,y=1,k=.06] % pms  124 uncoated m
+
+\definespotcolor [my-blue-100]   [my-blue]   [p=1]
+\definespotcolor [my-yellow-100] [my-yellow] [p=1]
+\definespotcolor [my-blue-50]    [my-blue]   [p=.5]
+\definespotcolor [my-yellow-50]  [my-yellow] [p=.5]
+
+\definemultitonecolor [my-mix] [my-blue=.12,my-yellow=.28] [c=.1,m=.1,y=.3,k=.1]
+\stopbuffer
+
+\typebuffer \getbuffer
+
+These colors show up as:
+
+\starttabulate[|T||]
+\NC my-blue       \NC \blackrule[color=my-blue,      width=.6\textwidth,height=5mm] \NC \NR
+\NC my-blue-50    \NC \blackrule[color=my-blue-50,   width=.6\textwidth,height=5mm] \NC \NR
+\NC my-blue-100   \NC \blackrule[color=my-blue-100,  width=.6\textwidth,height=5mm] \NC \NR
+\NC my-yellow     \NC \blackrule[color=my-yellow,    width=.6\textwidth,height=5mm] \NC \NR
+\NC my-yellow-50  \NC \blackrule[color=my-yellow-50, width=.6\textwidth,height=5mm] \NC \NR
+\NC my-yellow-100 \NC \blackrule[color=my-yellow-100,width=.6\textwidth,height=5mm] \NC \NR
+\NC my-mix        \NC \blackrule[color=my-mix,       width=.6\textwidth,height=5mm] \NC \NR
+\stoptabulate
+
+\useexternalfigure[demofig][mill.png][object=no,width=.2\textwidth]
+
+\startbuffer
+\startcombination[4*1]
+  {\externalfigure[demofig]}                      {no color}
+  {\externalfigure[demofig][color=my-mix]}        {indexed duotone}
+  {\externalfigure[demofig][color=my-blue-100]}   {spot color}
+  {\externalfigure[demofig][color=my-yellow-100]} {spot color}
+\stopcombination
+\stopbuffer
+
+\typebuffer
+
+This time we don't call an external program but we add an indexed color map to the
+image. The result can be seen in \in {figure} [fig:reindexing].
+
+\startplacefigure[reference=fig:reindexing,title={Reindexing bitmap images.}]
+    \getbuffer
+\stopplacefigure
+
+\stopsection
+
+\startsection[title=Profiles]
+
+Color profiles are used to control the printing process. There is some (limited)
+support for that built in. An example of a setup that we use in a project is the
+following:
+
+\starttyping
+\setupexternalfigures
+  [order={pdf,eps,png,jpg},
+   conversion=cmyk.pdf,
+   method=auto]
+\stoptyping
+
+So, we prefer \PDF\ vector images, if needed converted from \EPS. When there is
+no vector image we check for a \PNG\ and as last resort for a \JPG. The
+\type{method} is set to \type {auto} which means that we check if the image file
+indeed is reflected in the suffix. This is needed because in a workflow with tens
+of thousands of images there can be bad ones.
+
+The \type {conversion} parameter will make \CONTEXT\ check if there is a \type
+{cmyk.pdf} converter defined and when that is the case, it's applied. That
+specific converter will add a color profile to the image. You can set the
+profiles with:
+
+\starttyping
+\enabledirectives[graphics.conversion.rgbprofile=srgb.icc]
+\enabledirectives[graphics.conversion.cmykprofile=isocoated_v2_eci.icc]
+\stoptyping
+
+and these happens to be the defaults. You have to make sure that the files are
+present, preferable in \type{t:/texmf/colors/icc/context}. If you add profiles
+you need to make sure that \type {colorprofiles.lua} is updated accordingly.
+
+Just for completeness, in our situation, we also have set:
+
+\starttyping
+\enabledirectives[graphics.conversion.eps.cleanup.ai]
+\enabledirectives[graphics.extracheck]
+\stoptyping
+
+The first directive will make sure that confusing sections (for instance meant to
+the drawing program) are stripped from an \EPS\ file, and the second one forces
+some extra checking on the image (just to make sure that the engine doesn't exit
+on bad images).
+
+\stopsection
+
+\stopchapter
+
+\stopcomponent
diff --git a/doc/context/sources/general/manuals/colors/colors-introduction.tex b/doc/context/sources/general/manuals/colors/colors-introduction.tex
new file mode 100644
index 000000000..ba1db9915
--- /dev/null
+++ b/doc/context/sources/general/manuals/colors/colors-introduction.tex
@@ -0,0 +1,49 @@
+% language=uk
+
+\startcomponent colors-introduction
+
+\environment colors-environment
+
+\startchapter[title=Introduction][color=darkgray]
+
+This manual fits in the series where we discus fundamental subsystems like fonts
+and languages. Here we will collect the more technical backgrounds. This document
+is not meant as a manual for users who start with \CONTEXT, for that we have
+other manuals.
+
+Color has a rather long history in \CONTEXT\ because we supported it right from
+the start. In the times that \DVI\ backend drivers were used, specials were the
+way to force color in the result. However, each driver had different demands:
+some expected specific color directives, others a sequence of for instance
+\POSTSCRIPT\ commands. When \PDF\ showed up, resource management entered the
+game. Because ot always used a backend driver model in \CONTEXT, it could easily
+be adapted. All management, for instance of nested colors, was done in \TEX\
+code. If advanced color support hadn't been available right from the start, we'd
+probably not be using \TEX\ now.
+
+In \MKIV\ color support was implemented from scratch but in a for the user
+downward compatible way. In that respect this manual is not going to reveal
+anything revolutionary. Much of the work is now delegated to \LUA\ and because of
+that directives are no longer part of the (expanded) input stream. As a result
+color is now more robust and less intrusive.
+
+Because \METAPOST\ support is well integrated, we also communicate colors to
+\METAPOST. In \MKIV\ the communication between the two engines was upgraded and
+hopefully evolved into an (even) more convenient interface.
+
+External graphics are in fact islands in the document flow: they manage their
+resources like colors themselves. However, there are some ways to deal with the
+demands of publishers and printers with respect to colors. These will be
+discussed too.
+
+\getbuffer[underconstruction]
+
+\startlines
+Hans Hagen
+PRAGMA ADE, Hasselt NL
+2016
+\stoplines
+
+\stopchapter
+
+\stopcomponent
diff --git a/doc/context/sources/general/manuals/colors/colors-metafun.tex b/doc/context/sources/general/manuals/colors/colors-metafun.tex
new file mode 100644
index 000000000..82514659b
--- /dev/null
+++ b/doc/context/sources/general/manuals/colors/colors-metafun.tex
@@ -0,0 +1,695 @@
+% language=uk
+
+\startcomponent colors-basics
+
+\environment colors-environment
+
+\startchapter[title=Metafun][color=darkyellow]
+
+\startsection[title=Defining and using]
+
+In \METAPOST\ itself colors are defined as numbers or sets:
+
+\starttyping
+color     red  ; red  := (1,0,0) ;
+cmykcolor cyan ; cyan := (1,0,0,0) ;
+numeric   gray ; gray := 0.5 ;
+\stoptyping
+
+You don't need much fantasy to see that this fits well in the data model of
+\METAPOST. In fact, transparency could be represented as a \type {pair}. The
+disadvantage of having no generic color type is that you cannot mix them. In case
+you need to manipulate them, you can check the type:
+
+\starttyping
+if cmykcolor cyan : ... fi ;
+\stoptyping
+
+because \METAFUN\ is tightly integrated in \CONTEXT\ you can refer to colors
+known at the \TEX\ end by string. So,
+
+\starttyping
+string mycolor ; mycolor := "red" ;
+\stoptyping
+
+and then:
+
+\starttyping
+fill fullcircle scaled 4cm withcolor mycolor ;
+\stoptyping
+
+is quite okay. For completeness we also have \type {namedcolor} but it's not
+really needed:
+
+\starttyping
+fill fullcircle scaled 4cm withcolor namedcolor("red");
+\stoptyping
+
+You can define spot colors too but normally you will refer to colors
+defined at the \TEX\ end.
+
+\startbuffer[spot]
+\startMPcode
+    fill fullcircle scaled 3cm withcolor
+        .5 * spotcolor("whatever",(.3,.4,.5)) ;
+    fill fullcircle scaled 2cm withcolor
+             spotcolor("whatever",(.3,.4,.5)) ;
+    fill fullcircle scaled 1cm withcolor
+             spotcolor("whatever",(.3,.4,.5)/2) ;
+\stopMPcode
+\stopbuffer
+
+\startbuffer[multi]
+\startMPcode
+    fill fullcircle scaled 3cm withcolor
+        .5 * multitonecolor("whatever",(.3,.4,.5),(.5,.3,.4)) ;
+    fill fullcircle scaled 2cm withcolor
+             multitonecolor("whatever",(.3,.4,.5),(.5,.3,.4)) ;
+    fill fullcircle scaled 1cm withcolor
+             multitonecolor("whatever",(.3,.4,.5)/2,(.5,.3,.4)/2) ;
+\stopMPcode
+\stopbuffer
+
+\typebuffer[spot]
+
+Multitones are defined as:
+
+\typebuffer[multi]
+
+Some \PDF\ renderers have problems with fractions of such colors and even display
+the wrong colors. So, in these examples the third alternative in the sets of
+three might be more robust than the first. The result is shown in \in {figure}
+[fig:mpspot].
+
+\startplacefigure[reference=fig:mpspot,title={Spot and multitones directly defined in \METAFUN.}]
+    \startcombination[2*1]
+        {\getbuffer[spot]}  {}
+        {\getbuffer[multi]} {}
+    \stopcombination
+\stopplacefigure
+
+\stopsection
+
+\startsection[title=Passing colors]
+
+Originally \TEX\ and \METAPOST\ were separated processes and even in \LUATEX\
+they still are. There can be many independent \METAPOST\ instances present, but
+always there is \LUA\ as glue between them. In the early days of \LUATEX\ this
+was a one way channel: the \METAPOST\ output is available at the \TEX\ end in
+\LUA\ as a table and properties are used to communicate extensions. In today's
+\LUATEX\ the \METAPOST\ library has access to \LUA\ itself so that gives us a
+channel to \TEX, although with some limitations.
+
+Say that we have a color defined as follows:
+
+\startbuffer
+\definecolor[MyColor][r=.25,g=.50,b=.75]
+\stopbuffer
+
+\typebuffer \getbuffer
+
+We can apply this to a rule:
+
+\startbuffer
+\blackrule[color=MyColor,width=3cm,height=1cm,depth=0cm]
+\stopbuffer
+
+\typebuffer
+
+From this we get:
+
+\startlinecorrection
+\getbuffer
+\stoplinecorrection
+
+In \TEX\ (code) we can do this:
+
+\startbuffer
+\startMPcode
+    fill unitsquare xyscaled (3cm,1cm) withcolor \MPcolor {MyColor} ;
+\stopMPcode
+\stopbuffer
+
+\typebuffer
+
+When the code is pushed to \METAPOST\ the color gets expanded, in this case to
+\typ {(0.25, 0.50, 0.75)} because we specified an \RGB\ color but the other
+colorspaces are supported too.
+
+\startlinecorrection
+\getbuffer
+\stoplinecorrection
+
+Equally valid code is:
+
+\starttyping
+\startMPcode
+    fill unitsquare xyscaled (3cm,1cm) withcolor "MyColor" ;
+\stopMPcode
+\stoptyping
+
+This is very un-\METAPOST\ as naturally it can only deal with numerics for gray
+scales, triplets for \RGB\ colors, and quadruplets for \CMYK\ colors. In
+\METAFUN\ (as present in \CONTEXT\ MKIV) the \type {withcolor} operator also
+accepts a string, which is resolved to a color specification.
+
+For the record we note that when you use transparent colors, a more complex
+specification gets passed with \type {\MPcolor} or resolved (via the string). The
+same is true for spot and multitone colors. It will be clear that when you want
+to assign a color to a variable you have to make sure the type matches. A rather
+safe way to define colors is:
+
+\starttyping
+def MyColor =
+    \MPcolor{MyColor}
+enddef ;
+\stoptyping
+
+and because we can use strings, string variables are also an option.
+
+\stopsection
+
+\startsection[title=Grouping]
+
+The reason for discussing these details is that there is a rather fundamental
+concept of grouping in \TEX\ which can lead to unexpected side effects. The
+reason is that there is no grouping at the \LUA\ end, unless one uses a kind of
+stack, and that in \METAPOST\ grouping is an explicit feature.
+
+\starttyping
+\scratchcounter=123
+\bgroup
+    \scratchcounter=456
+\egroup
+\stoptyping
+
+After this \TEX\ code is expanded the counter has value 123. In \METAPOST\ you
+can do the following:
+
+\starttyping
+scratchcounter := 123 ;
+\begingroup
+    scratchcounter := 456 ;
+\endgroup
+\stoptyping
+
+but here the counter is 456 afterwards! You explicitly need to save a value:
+
+\starttyping
+scratchcounter := 123 ;
+\begingroup
+    save scratchcounter ;
+    numeric scratchcounter ; % variables are numeric by default anyway
+    scratchcounter := 456 ;
+\endgroup
+\stoptyping
+
+The difference perfectly makes sense if you think about the kind of applications
+\TEX\ and \METAPOST\ are used for. In \LUA\ you can do this:
+
+
+\starttyping
+scratchcounter = 123
+do
+    local scratchcounter = 456
+end
+\stoptyping
+
+and in fact, a \type {then}, \type {else}, \type {while}, \type {repeat}, \type
+{do} and function body also behave this way.
+
+So, what is the impact on colors? Imagine that you do this:
+
+\startbuffer
+\bgroup
+    \definecolor[MyColor][s=.5]
+    \startMPcode
+        pickup pencircle scaled 4mm ;
+        draw fullcircle scaled 30mm withcolor \MPcolor{MyColor} ;
+        draw fullcircle scaled 15mm withcolor "MyColor" ;
+    \stopMPcode
+\egroup
+\quad
+\startMPcode
+    pickup pencircle scaled 4mm ;
+    draw fullcircle scaled 30mm withcolor \MPcolor{MyColor} ;
+    draw fullcircle scaled 15mm withcolor "MyColor" ;
+\stopMPcode
+\stopbuffer
+
+\typebuffer
+
+We get the following colors:
+
+\startlinecorrection
+\hbox{\getbuffer}
+\stoplinecorrection
+
+Because \type {\MPcolor} is a \TEX\ macro, its value gets expanded when the
+graphic is calculated. After the group (first graphic) the color is restored.
+But, in order to access the colors defined at the \TEX\ end in \METAPOST\ by name
+(using \LUA) we need to make sure that a defined color is registered at that end.
+Before we could use the string accessor in \METAPOST\ colors, this was never a
+real issue. We kept the values in a (global) \LUA\ table which was good enough
+for the cases where we wanted to access color specifications, for instance for
+tracing. Such colors never changed in a document. But with the more dynamic
+\METAPOST\ graphics we cannot do that: there is no way that \METAPOST\ (or \LUA)
+later on can know that the color was defined inside a group as clone. For daily
+usage it's enough to know that we have found a way around it in \CONTEXT\ at
+neglectable overhead. In the rare case this mechanism fails, you can always
+revert to the \type {\MPcolor} method.
+
+\startbuffer
+\definecolor[DemoOne][red]
+\definecolor[DemoTwo][s=.8,t=0.5,a=1]
+
+%definepalet[DemoPalet][NumberColor={g=1}]
+\definepalet[DemoPalet][NumberColor=red,red=cyan]
+\definepalet[DemoPalet][NumberColor=red]
+
+\setuppalet[DemoPalet]
+
+\bgroup
+    \definecolor[red]    [b=.8]
+    \definecolor[DemoOne][yellow]
+    \startMPcode
+        fill fullcircle scaled 10 withcolor "NumberColor" ;
+        fill fullcircle scaled  7 withcolor "red" ;
+        fill fullcircle scaled  6 withcolor .5\MPcolor{red} ;
+        fill fullcircle scaled  4 shifted (-4,0) withcolor \MPcolor{DemoTwo} ;
+        fill fullcircle scaled  4 shifted ( 4,0) withcolor "DemoTwo" ;
+        fill fullcircle scaled  2 withcolor "DemoOne" ;
+        fill fullcircle scaled  1 withcolor \MPcolor{NumberColor} ;
+        currentpicture := currentpicture xysized(5cm,3cm) ;
+    \stopMPcode
+\egroup
+\hskip1cm
+\startMPcode
+    fill fullcircle scaled 10 withcolor "NumberColor" ;
+    fill fullcircle scaled  7 withcolor "red" ;
+    fill fullcircle scaled  6 withcolor .5\MPcolor{red} ;
+    fill fullcircle scaled  4 shifted (-4,0) withcolor \MPcolor{DemoTwo} ;
+    fill fullcircle scaled  4 shifted ( 4,0) withcolor "DemoTwo" ;
+    fill fullcircle scaled  2 withcolor "DemoOne" ;
+    fill fullcircle scaled  1 withcolor \MPcolor{NumberColor} ;
+        currentpicture := currentpicture xysized(5cm,3cm) ;
+\stopMPcode
+\stopbuffer
+
+The following example was used when developing the string based color resolver.
+The complication was in getting the color palets resolved right without too much
+overhead. Again we demonstrate this because border cases might occur that are not
+catched (yet).
+
+\startlinecorrection
+    \hbox {\getbuffer}
+\stoplinecorrection
+
+\stopsection
+
+\startsection[title=Transparency]
+
+Transparency is supported at the \TEX\ end: either or not bound to colors. We
+already saw how to use colors, here's how to apply transparency:
+
+\startbuffer
+\startMPcode
+    fill fullsquare xyscaled (4cm,2cm) randomized 5mm
+        withcolor "darkred" ;
+    fill fullsquare xyscaled (2cm,4cm) randomized 5mm
+        withcolor "darkblue" withtransparency ("normal",0.5) ;
+
+    fill fullsquare xyscaled (4cm,2cm) randomized 5mm shifted (45mm,0)
+        withcolor "darkred"  withtransparency ("normal",0.5) ;
+    fill fullsquare xyscaled (2cm,4cm) randomized 5mm shifted (45mm,0)
+        withcolor "darkblue" withtransparency ("normal",0.5) ;
+
+    fill fullsquare xyscaled (4cm,2cm) randomized 5mm shifted (90mm,0)
+        withcolor "darkred"  withtransparency ("normal",0.5) ;
+    fill fullsquare xyscaled (2cm,4cm) randomized 5mm shifted (90mm,0)
+        withcolor "darkblue" ;
+\stopMPcode
+\stopbuffer
+
+\typebuffer
+
+We get a mixture of normal and transparent colors. Instead of \type {normal}
+you can also pass a number (with \type {1} being \type {normal}).
+
+\startlinecorrection
+    \getbuffer
+\stoplinecorrection
+
+\stopsection
+
+\startsection[title=Shading]
+
+Shading is available too. This mechanism is a bit more complex deep down because
+it needs resources as well as shading vectors that adapt themselves to the current
+scale. We will not go into detail about the shading properties here.
+
+\startbuffer
+\startMPcode
+    comment("two shades with mp colors");
+    fill fullcircle scaled 5cm
+        withshademethod "circular"
+        withshadevector (2cm,1cm)
+        withshadecenter (.1,.5)
+        withshadedomain (.2,.6)
+        withshadefactor 1.2
+        withshadecolors (red,white)
+        ;
+    fill fullcircle scaled 5cm shifted (6cm,0)
+        withshademethod "circular"
+        withcolor "red" shadedinto "blue"
+    ;
+\stopMPcode
+\stopbuffer
+
+\typebuffer
+
+You can use normal \METAPOST\ colors as well as named colors.
+
+\startlinecorrection
+    \getbuffer
+\stoplinecorrection
+
+\startbuffer
+\startMPcode
+    comment("two shades with named colors");
+    fill fullcircle scaled 5cm
+        withshademethod "circular"
+        withshadecolors ((1,0,0),(0,0,1,0))
+    ;
+    fill fullcircle scaled 5cm shifted (6cm,0)
+        withshademethod "circular"
+        withcolor (1,0,0,0) shadedinto "blue"
+    ;
+\stopMPcode
+\stopbuffer
+
+The color space of the first color determines if the second one needs
+to be converted, so this is valid:
+
+\typebuffer
+
+The first circle is in \RGB\ colors and the second in \CMYK.
+
+\startlinecorrection
+    \getbuffer
+\stoplinecorrection
+
+You cannot use spot colors but you can use transparency, so with:
+
+\startbuffer
+\startMPcode
+    comment("three transparent shades");
+    fill fullcircle scaled 5cm
+        withshademethod "circular"
+        withshadecolors ("red","green")
+        withtransparency ("normal",0.5)
+    ;
+    fill fullcircle scaled 5cm shifted (30mm,0)
+        withshademethod "circular"
+        withshadecolors ("green","blue")
+        withtransparency ("normal",0.5)
+    ;
+    fill fullcircle scaled 5cm shifted (60mm,0)
+        withshademethod "circular"
+        withshadecolors ("blue","yellow")
+        withtransparency ("normal",0.5)
+    ;
+\stopMPcode
+\stopbuffer
+
+\typebuffer
+
+we get:
+
+\startlinecorrection
+    \getbuffer
+\stoplinecorrection
+
+You can define a shade and use it later on, for example:
+
+\startbuffer
+\startMPcode
+    defineshade myshade
+        withshademethod "circular"
+        withshadefactor 1
+        withshadedomain (0,1)
+        withshadecolors (black,white)
+        withtransparency (1,.5)
+    ;
+
+    fill fullcircle xyscaled(.75TextWidth,4cm)
+        shaded myshade ;
+    fill fullcircle xyscaled(.75TextWidth,4cm) shifted (.125TextWidth,0)
+        shaded myshade ;
+    fill fullcircle xyscaled(.75TextWidth,4cm) shifted (.25TextWidth,0)
+        shaded myshade ;
+\stopMPcode
+\stopbuffer
+
+\typebuffer
+
+This gives three transparent shaded shapes:
+
+\startlinecorrection
+    \getbuffer
+\stoplinecorrection
+
+A very special shade is the following:
+
+\startbuffer
+\startMPcode
+    fill fullsquare yscaled 5ExHeight xscaled TextWidth
+        withshademethod "linear"
+        withshadevector (0,1)
+        withshadestep (
+            withshadefraction .3
+            withshadecolors (red,green)
+        )
+        withshadestep (
+            withshadefraction .5
+            withshadecolors (green,blue)
+        )
+        withshadestep (
+            withshadefraction .7
+            withshadecolors (blue,red)
+        )
+        withshadestep (
+            withshadefraction 1
+            withshadecolors (red,yellow)
+        )
+    ;
+\stopMPcode
+\stopbuffer
+
+\typebuffer
+
+The result is a colorful band:
+
+\startlinecorrection
+    \getbuffer
+\stoplinecorrection
+
+\stopsection
+
+\startsection[title=Text]
+
+The text typeset with \type {textext} is processed in \TEX\ using the
+current settings. A text can of course have color directives embedded.
+
+\startbuffer
+\startMPcode
+numeric u ; u := 8mm ;
+draw thetextext("RED",                     (0,0u)) withcolor darkred ;
+draw thetextext("\darkgreen GREEN",        (0,1u)) ;
+draw thetextext("\darkblue   BLUE",        (0,2u)) withcolor darkred ;
+draw thetextext("BLACK {\darkgreen GREEN}",(0,3u)) ;
+draw thetextext("RED   {\darkblue   BLUE}",(0,4u)) withcolor darkred ;
+\stopMPcode
+\stopbuffer
+
+\typebuffer
+
+In this example we demonstrate that you can also apply a color to the
+resulting picture.
+
+\startlinecorrection
+\tttfd \getbuffer
+\stoplinecorrection
+
+\stopsection
+
+\startsection[title=Helpers]
+
+\stopsection
+
+There are several color related macros in \METAFUN\ and these are discussed
+in the \METAFUN\ manual, so we only mention a few here.
+
+\startbuffer
+\startMPcode
+    fill fullsquare xyscaled(TextWidth,4cm)
+        withcolor darkred ;
+    fill fullsquare xyscaled(TextWidth,3cm)
+        withcolor complementary darkred ;
+    fill fullsquare xyscaled(TextWidth,2cm)
+        withcolor complemented darkred ;
+    fill fullsquare xyscaled(TextWidth,1cm)
+        withcolor grayed darkred ;
+\stopMPcode
+\stopbuffer
+
+\typebuffer
+
+This example code is shown in \in {figure} [fig:complemen-1]. The \type
+{complementary} operator subtracts the given color from white, the \type
+{complemented} operator calculates its values from opposites (so a zero becomes a
+one). In \in {figure} [fig:complemen-2] a more extensive example is shown.
+
+\startplacefigure
+    [reference=fig:complemen-1,
+     title={The \type {complementary}, \type {complemented} and \type
+     {grayed} methodscompared.}]
+    \getbuffer
+\stopplacefigure
+
+\startMPdefinitions
+    % This is an old example I had laying around since 2005. The original was just
+    % a framed text with the graphic as background but here I use textext instead.
+    def MyCompare (text method) =
+
+        picture p ; p := textext("\quad \bf
+            I don't understand about complementary colors\quad
+            And what they say\quad
+            Side by side they both get bright\quad
+            Together they both get gray\quad"
+        ) ;
+
+        numeric w ; w := bbwidth  p ;
+        numeric h ; h := bbheight p ;
+
+        for i = 1 upto 10 :
+            fill fullsquare
+                xscaled (w/10)
+                yscaled 5h
+                shifted (-w/2-w/20+i*w/10,-3h/2)
+                withcolor (i*red/10)
+                withtransparency(1,.5) ;
+            fill fullsquare
+                xscaled (w/10)
+                yscaled 5h
+                shifted (-w/2-w/20+i*w/10,3h/2)
+                withcolor method (i*red/10)
+                withtransparency(1,.5) ;
+        endfor ;
+        addbackground withcolor .75white ;
+
+        draw p withcolor white ;
+
+        currentpicture := currentpicture xsized TextWidth ;
+    enddef ;
+\stopMPdefinitions
+
+\startplacefigure[reference=fig:complemen-2,title={Two methods to complement colors compared (text: Fiona Apple).}]
+    \startcombination[1*2]
+        {\startMPcode MyCompare(complemented)  ; \stopMPcode} {complemented}
+        {\startMPcode MyCompare(complementary) ; \stopMPcode} {complementary}
+    \stopcombination
+\stopplacefigure
+
+As we discussed before, the different color models in \METAPOST\ cannot be mixed
+in expressions. We therefore have two macros that expand into white or black
+in the right colorspace.
+
+\typebuffer
+
+\startbuffer
+\startMPcode
+    fill fullsquare xyscaled(TextWidth,4cm)
+        withcolor .5[(.5,0,0),   whitecolor (.5,0,0)] ;
+    fill fullsquare xyscaled(TextWidth,3cm)
+        withcolor .5[(.5,0,0),   blackcolor (.5,0,0)] ;
+    fill fullsquare xyscaled(TextWidth,2cm)
+        withcolor .5[(.5,0,0,0), whitecolor (.5,0,0,0)] ;
+    fill fullsquare xyscaled(TextWidth,1cm)
+        withcolor .5[(.5,0,0,0), blackcolor (.5,0,0,0)] ;
+\stopMPcode
+\stopbuffer
+
+\typebuffer
+
+\startlinecorrection
+\getbuffer
+\stoplinecorrection
+
+There are two macros that can be used to resolve string to colors: \type
+{resolvedcolor} and \type {namedcolor}. A resolved color is expanded via \LUA\
+while a named color is handled in the backend, when the result is converted to
+\PDF. The resolved approach is more recent and is the same as a string color
+specification.
+
+\startbuffer
+\startMPcode
+    fill fullcircle scaled 4cm withcolor .5 resolvedcolor "darkred" ;
+    fill fullcircle scaled 3cm withcolor .5 resolvedcolor "gray" ;
+    fill fullcircle scaled 2cm withcolor .5 namedcolor    "darkblue" ;
+    fill fullcircle scaled 1cm withcolor .5 namedcolor    "gray" ;
+\stopMPcode
+\stopbuffer
+
+\typebuffer
+
+\startlinecorrection
+\getbuffer
+\stoplinecorrection
+
+There is a \type {drawoptions} macro that can be used to define properties in one go.
+
+\startbuffer
+\startMPcode
+    drawoptions(withcolor "darkgreen");
+    fill fullcircle scaled 4cm  ;
+    fill fullcircle scaled 3cm withcolor white ;
+    fill fullcircle scaled 2cm ;
+\stopMPcode
+\stopbuffer
+
+\typebuffer
+
+We get:
+
+\startlinecorrection
+\getbuffer
+\stoplinecorrection
+
+The drawback of this approach is that, because we use so called pre- and
+postscripts for achieving special effects (like spotcolors and shading)
+successive \type {withcolor} calls can interfere in a way that unexpected results
+turn up. A way out is to use properties:
+
+\startbuffer
+\startMPcode
+    property p[] ;
+    p1 = properties(withcolor "darkred") ;
+    p2 = properties(withcolor "white") ;
+    fill fullcircle scaled 4cm withproperties p1 ;
+    fill fullcircle scaled 3cm withproperties p2 ;
+    fill fullcircle scaled 2cm withproperties p1 ;
+\stopMPcode
+\stopbuffer
+
+\typebuffer
+
+This results in:
+
+\startlinecorrection
+\getbuffer
+\stoplinecorrection
+
+\stopchapter
+
+\stopcomponent
diff --git a/doc/context/sources/general/manuals/colors/colors-mkiv.tex b/doc/context/sources/general/manuals/colors/colors-mkiv.tex
new file mode 100644
index 000000000..064758ba3
--- /dev/null
+++ b/doc/context/sources/general/manuals/colors/colors-mkiv.tex
@@ -0,0 +1,54 @@
+% language=uk
+
+% author    : Hans Hagen
+% copyright : PRAGMA ADE & ConTeXt Development Team
+% license   : Creative Commons Attribution ShareAlike 4.0 International
+% reference : pragma-ade.nl | contextgarden.net | texlive (related) distributions
+% origin    : the ConTeXt distribution
+%
+% comment   : Because this manual is distributed with TeX distributions it comes with a rather
+%             liberal license. We try to adapt these documents to upgrades in the (sub)systems
+%             that they describe. Using parts of the content otherwise can therefore conflict
+%             with existing functionality and we cannot be held responsible for that. Many of
+%             the manuals contain characteristic graphics and personal notes or examples that
+%             make no sense when used out-of-context.
+
+%             \nopdfcompression
+
+\enablemode[simple] % ,oversized
+
+\startbuffer[abstract]
+
+    This book is about colors and how to use them in \CONTEXT\ \MKIV, including
+    \METAFUN. Although the basics are not that complex, a bit of insight in how
+    they are implemented and what can be done might help in creating more
+    interesting looking documents.
+
+\stopbuffer
+
+\environment colors-environment
+
+\startdocument
+  [author=Hans Hagen,
+   title=Coloring \ConTeXt,
+   subtitle=explaining luatex and mkiv,
+   affiliation=PRAGMA ADE,
+   comment=work in progress,
+   cover:color:1=darkgreen,
+   cover:color:2=darkyellow,
+   cover:color:3=darkblue,
+   cover:color:4=darkmagenta,
+   cover:color:5=darkgray]
+
+    \startfrontmatter
+        \component manuals-explaining-contents
+        \component colors-introduction
+    \stopfrontmatter
+
+    \startbodymatter
+        \component colors-basics
+        \component colors-metafun
+        \component colors-graphics
+    \stopbodymatter
+
+\stopdocument
diff --git a/doc/context/sources/general/manuals/luatex/luatex.tex b/doc/context/sources/general/manuals/luatex/luatex.tex
index f571515ae..90484aa7e 100644
--- a/doc/context/sources/general/manuals/luatex/luatex.tex
+++ b/doc/context/sources/general/manuals/luatex/luatex.tex
@@ -13,7 +13,7 @@
 
 \startdocument
   [%status=release,
-   version=1.0.0]
+   version=1.0.1]
 
 \component luatex-titlepage
 
diff --git a/doc/context/sources/general/manuals/math/math-mkiv.tex b/doc/context/sources/general/manuals/math/math-mkiv.tex
index d9785c8a8..291a99c9e 100644
--- a/doc/context/sources/general/manuals/math/math-mkiv.tex
+++ b/doc/context/sources/general/manuals/math/math-mkiv.tex
@@ -32,6 +32,7 @@
     \component math-numbering
     \component math-combining
     \component math-features
+    \component math-tricks
 \stopbodymatter
 
 \stopdocument
diff --git a/doc/context/sources/general/manuals/spreadsheets/spreadsheets-mkiv.tex b/doc/context/sources/general/manuals/spreadsheets/spreadsheets-mkiv.tex
new file mode 100644
index 000000000..4dfd133ad
--- /dev/null
+++ b/doc/context/sources/general/manuals/spreadsheets/spreadsheets-mkiv.tex
@@ -0,0 +1,756 @@
+% language=uk
+
+% author    : Hans Hagen
+% copyright : PRAGMA ADE & ConTeXt Development Team
+% license   : Creative Commons Attribution ShareAlike 4.0 International
+% reference : pragma-ade.nl | contextgarden.net | texlive (related) distributions
+% origin    : the ConTeXt distribution
+%
+% comment   : Because this manual is distributed with TeX distributions it comes with a rather
+%             liberal license. We try to adapt these documents to upgrades in the (sub)systems
+%             that they describe. Using parts of the content otherwise can therefore conflict
+%             with existing functionality and we cannot be held responsible for that. Many of
+%             the manuals contain characteristic graphics and personal notes or examples that
+%             make no sense when used out-of-context.
+
+\usemodule[spreadsheet]
+\usemodule[art-01,abr-02]
+
+\definecolor[darkred]  [r=.4]
+\definecolor[darkgreen][g=.4]
+\definecolor[darkblue] [b=.4]
+
+\definecolor[maincolor] [darkred]
+\definecolor[extracolor][darkblue]
+
+\setuptyping
+  [color=extracolor]
+
+\setuptype
+  [color=extracolor]
+
+\setuphead
+  [section]
+  [color=maincolor]
+
+\setupbodyfont
+  [10pt]
+
+\setupinteraction
+  [hidden]
+
+% \setupnumbering
+%   [alternative=doublesided]
+
+\startdocument
+  [metadata:author=Hans Hagen,
+   metadata:title=Simple Spreadsheets,
+   author=Hans Hagen,
+   affiliation=PRAGMA ADE,
+   location=Hasselt NL,
+   title=Simple Spreadsheets,
+   extra=ConTeXt MkIV,
+   support=www.contextgarden.net,
+   website=www.pragma-ade.nl]
+
+\startMPpage
+
+    StartPage;
+
+    numeric n, m ; n := 3 * 4 ; m := 4 * 4 ;
+    numeric w, h ; w := PaperWidth/n ; h := PaperHeight/m ;
+
+    for i=1 upto n :
+        for j=1 upto m :
+            fill
+                unitsquare
+                xysized (w,h)
+                shifted ((i-1)*w,(j-1)*h)
+                withcolor .5[i*red/n,j*blue/m]
+            ;
+        endfor ;
+    endfor ;
+
+    for i=1 upto n :
+        for j=1 upto m :
+            draw
+                textext("\tt" & char(64+i) & if j < 10 : "0" else : "" fi & decimal j)
+                xysized (.7*w,.7*h)
+                shifted (i*w-.5w,(m+1-j)*h-.5h)
+                withcolor .5[(n+1-i)*green/n,(m+1-j)*yellow/m]
+            ;
+        endfor ;
+    endfor ;
+
+    draw
+        textext.llft("\ssbf{\documentvariable{title}}")
+        xsized (PaperHeight-h)
+        rotated 90
+        shifted (PaperWidth-1.75w,PaperHeight-h/2)
+        withcolor white
+    ;
+
+    draw
+        textext.llft("\ssbf{\documentvariable{extra}}")
+        ysized (h/2)
+        shifted (PaperWidth-2.5w,3.75h)
+        withcolor white
+    ;
+
+
+    draw
+        textext.llft("\ssbf{\documentvariable{author}}")
+        ysized (h/2)
+        shifted (PaperWidth-2.5w,2.75h)
+        withcolor white
+    ;
+
+    draw
+        textext.llft("\ssbf \currentdate")
+        ysized (h/2)
+        shifted (PaperWidth-2.5w,1.75h)
+        withcolor white
+    ;
+
+    StopPage;
+
+\stopMPpage
+
+% \page[empty] \setuppagenumber[start=1]
+
+\startsubject[title={Contents}]
+
+\placelist[section][criterium=all,interaction=all]
+
+\stopsubject
+
+\startsection [title={Introduction}]
+
+Occasionally a question pops up on the \CONTEXT\ mailing list and answering it
+becomes a nice distraction from a boring task at hand. The spreadsheet module is
+the result of such a diversion. As with more support code in \CONTEXT, this is
+not a replacement for \quote {the real thing} but just a nice feature for simple
+cases. The module is loaded with
+
+\starttyping
+\usemodule[spreadsheet]
+\stoptyping
+
+So this is (at least currently) not one of the core functionalities but an
+add||on. Of course some useful extensions might appear in the future.
+
+\stopsection
+
+\startsection [title={Spreadsheet tables}]
+
+We can use \LUA\ in each cell, because under the hood it is all \LUA. There is
+some basic parsing applied so that we can use the usual \type {A..Z} variables to
+access cells.
+
+\startbuffer[demo]
+\startspreadsheettable[test]
+  \startrow
+    \startcell 1.1         \stopcell
+    \startcell 2.1         \stopcell
+    \startcell A[1] + B[1] \stopcell
+  \stoprow
+  \startrow
+    \startcell 2.1         \stopcell
+    \startcell 2.2         \stopcell
+    \startcell A[2] + B[2] \stopcell
+  \stoprow
+  \startrow
+    \startcell A[1] + B[1] \stopcell
+    \startcell A[2] + B[2] \stopcell
+    \startcell A[3] + B[3] \stopcell
+  \stoprow
+\stopspreadsheettable
+\stopbuffer
+
+\typebuffer[demo]
+
+The rendering is shown in \in {figure} [spreadsheet:1]. Keep in mind that in
+\LUA\ all calculations are done using floats, at least in \LUA\ versions with
+version numbers preceding 5.3.
+
+\placefigure
+  [here]
+  [spreadsheet:1]
+  {A simple spreadsheet.}
+  {\getbuffer[demo]}
+
+The last cell can also look like this:
+
+\starttyping
+\startcell
+function()
+  local s = 0
+  for i=1,2 do
+    for j=1,2 do
+      s = s + dat[i][j]
+    end
+  end
+  return s
+end
+\stopcell
+\stoptyping
+
+The content of a cell is either a number or a function. In this example
+we just loop over the (already set) cells and calculate their sum. The
+\type {dat} variable accesses the grid of cells.
+
+\starttyping
+\startcell
+function()
+  local s = 0
+  for i=1,2 do
+    for j=1,2 do
+      s = s + dat[i][j]
+    end
+  end
+  tmp.total = s
+end
+\stopcell
+\stoptyping
+
+In this variant we store the sum in the table \type {tmp} which is local to the
+current sheet. Another table is \type {fnc} where we can store functions. This
+table is shared between all sheets. There are two predefined functions:
+
+\starttyping
+sum(columnname,firstrow,lastrow)
+fmt(specification,n)
+\stoptyping
+
+The \type {sum} function works top||down in columns, and roughly looks like
+this:
+
+\starttyping
+function sum(currentcolumn,firstrow,lastrow)
+  local r = 0
+  for i = firstrow, lastrow do
+    r = r + cells[currentcolumn][i]
+  end
+  return r
+end
+\stoptyping
+
+The last two arguments are optional:
+
+\starttyping
+sum(columnname,lastrow)
+\stoptyping
+
+This is equivalent to:
+
+\starttyping
+function sum(currentcolumn,lastrow)
+  local r = 0
+  for i = 1, lastrow do
+    r = r + cells[currentcolumn][i]
+  end
+  return r
+end
+\stoptyping
+
+While:
+
+\starttyping
+sum(columnname)
+\stoptyping
+
+boils down to:
+
+\starttyping
+function sum(currentcolumn)
+  local r = 0
+  for i = 1, currentrow do
+    r = r + cells[currentcolumn][i]
+  end
+  return r
+end
+\stoptyping
+
+Empty cells or cells that have no numbers are skipped. Let's now see these
+functions in action:
+
+\startbuffer[demo]
+\startspreadsheettable[test]
+  \startrow
+    \startcell 1.1 \stopcell \startcell 2.1 \stopcell
+  \stoprow
+  \startrow
+    \startcell 2.1 \stopcell \startcell 2.2 \stopcell
+  \stoprow
+  \startrow
+    \startcell
+      function()
+        local s = 0
+        for i=1,2 do
+          for j=1,2 do
+            s = s + dat[i][j]
+          end
+        end
+        context.bold(s)
+      end
+    \stopcell
+    \startcell
+      function()
+        local s = 1
+        for i=1,2 do
+          for j=1,2 do
+            s = s * dat[i][j]
+          end
+        end
+        context.bold(fmt("@.1f",s))
+      end
+    \stopcell
+  \stoprow
+\stopspreadsheettable
+\stopbuffer
+
+\typebuffer[demo]
+
+The result is shown in \in {figure} [spreadsheet:2]. Watch the \type {fmt} call:
+we use an at sign instead of a percent to please \TEX.
+
+\placefigure
+  [here]
+  [spreadsheet:2]
+  {Cells can be (complex) functions.}
+  {\getbuffer[demo]}
+
+Keep in mind that we're typesetting and that doing complex calculations is not
+our main objective. A typical application of this module is in making bills, for
+which you can combine it with the correspondence modules. We leave that as an
+exercise for the reader and stick to a simple example.
+
+\startbuffer[demo]
+\startspreadsheettable[test]
+  \startrow
+    \startcell[align=flushleft,width=8cm] "item one" \stopcell
+    \startcell[align=flushright,width=3cm] @ "0.2f EUR" 3.50 \stopcell
+  \stoprow
+  \startrow
+    \startcell[align=flushleft] "item two" \stopcell
+    \startcell[align=flushright] @ "0.2f EUR" 8.45 \stopcell
+  \stoprow
+  \startrow
+    \startcell[align=flushleft] "tax 19\percent" \stopcell
+    \startcell[align=flushright] @ "0.2f EUR" 0.19 * (B[1]+B[2]) \stopcell
+  \stoprow
+  \startrow
+    \startcell[align=flushleft] "total 1" \stopcell
+    \startcell[align=flushright] @ "0.2f EUR" sum(B,1,3) \stopcell
+  \stoprow
+  \startrow
+    \startcell[align=flushleft] "total 2" \stopcell
+    \startcell[align=flushright] @ "0.2f EUR" B[1] + B[2] + B[3] \stopcell
+  \stoprow
+  \startrow
+    \startcell[align=flushleft] "total 3" \stopcell
+    \startcell[align=flushright] @ "0.2f EUR" sum(B) \stopcell
+  \stoprow
+\stopspreadsheettable
+\stopbuffer
+
+\typebuffer[demo]
+
+Here (and in \in {figure} [spreadsheet:8]) you see a quick and more
+readable way to format cell content. The \type {@} in the template is
+optional, but needed in cases like this:
+
+\starttyping
+@ "(@0.2f) EUR" 8.45
+\stoptyping
+
+A \type {@} is only prepended when no \type {@} is given in the template.
+
+\placefigure
+  [here]
+  [spreadsheet:8]
+  {Cells can be formatted by using \type {@} directives.}
+  {\getbuffer[demo]}
+
+In practice this table we can be less specific and let \type {\sum} behave more
+automatical. That way the coding can be simplified (see \in {figure}
+[spreadsheet:7]) and also look nicer.
+
+\startbuffer[demo]
+\startspreadsheettable[test][frame=off]
+  \startrow
+    \startcell[align=flushleft,width=8cm] "The first item" \stopcell
+    \startcell[align=flushright,width=3cm] @ "0.2f EUR" 3.50 \stopcell
+  \stoprow
+  \startrow
+    \startcell[align=flushleft] "The second item" \stopcell
+    \startcell[align=flushright] @ "0.2f EUR" 8.45 \stopcell
+  \stoprow
+  \startrow
+    \startcell[align=flushleft] "The third item" \stopcell
+    \startcell[align=flushright] @ "0.2f EUR" 5.90 \stopcell
+  \stoprow
+  \startrow[topframe=on]
+    \startcell[align=flushleft] "VAT 19\percent" \stopcell
+    \startcell[align=flushright] @ "0.2f EUR" 0.19 * sum(B) \stopcell
+  \stoprow
+  \startrow[topframe=on]
+    \startcell[align=flushleft] "\bf Grand total" \stopcell
+    \startcell[align=flushright] @ "0.2f EUR" sum(B) \stopcell
+  \stoprow
+\stopspreadsheettable
+\stopbuffer
+
+\typebuffer[demo]
+
+\placefigure
+  [here]
+  [spreadsheet:7]
+  {The \type {sum} function accumulates stepwise.}
+  {\getbuffer[demo]}
+
+There are a few more special start characters. This is demonstrated in \in
+{figure} [spreadsheet:9]. An \type {=} character is ignored. \footnote {Taco
+suggested to support this because some spreadsheet programs use that character to
+flush a value.} When we start with an \type {!}, the content is not typeset.
+Strings can be surrounded by single or double quotes and are not really
+processed.
+
+\startbuffer[demo]
+\startspreadsheettable[test][offset=1ex]
+  \startrow
+    \startcell[align=flushleft] "first" \stopcell
+    \startcell[align=flushleft] '\type{@ "[@i]" 1}' \stopcell
+    \startcell[align=flushright,width=3cm] @ "[@i]" 1 \stopcell
+  \stoprow
+  \startrow
+    \startcell[align=flushleft] "second" \stopcell
+    \startcell[align=flushleft] '\type{= 2}' \stopcell
+    \startcell[align=flushright] = 2 \stopcell
+  \stoprow
+  \startrow
+    \startcell[align=flushleft] "third" \stopcell
+    \startcell[align=flushleft] '\type{! 3}' \stopcell
+    \startcell[align=flushright] ! 3 \stopcell
+  \stoprow
+  \startrow
+    \startcell[align=flushleft] "fourth" \stopcell
+    \startcell[align=flushleft] '\type{4}' \stopcell
+    \startcell[align=flushright] 4 \stopcell
+  \stoprow
+  \startrow
+    \startcell[align=flushleft] "\bf total one" \stopcell
+    \startcell[align=flushleft] '\type{sum(C)}' \stopcell
+    \startcell[align=flushright] sum(C) \stopcell
+  \stoprow
+  \startrow
+    \startcell[align=flushleft] "\bf total two" \stopcell
+    \startcell[align=flushleft] '\type{= sum(C)}' \stopcell
+    \startcell[align=flushright] = sum(C) \stopcell
+  \stoprow
+\stopspreadsheettable
+\stopbuffer
+
+\typebuffer[demo]
+
+The \type {sum} function is clever enough not to include itself in the
+summation. Only preceding cells are taken into account, given that they
+represent a number.
+
+\placefigure
+  [here]
+  [spreadsheet:9]
+  {Cells can be hidden by \type {!} and can contain strings only.}
+  {\getbuffer[demo]}
+
+\stopsection
+
+\startsection [title={Normal tables}]
+
+In the previous examples we used \TEX\ commands for structuring the sheet but
+the content of cells is \LUA\ code. It is also possible to stick to a regular
+table and use specific commands to set and get cell data.
+
+\startbuffer[demo]
+\bTABLE[align=middle]
+  \bTR
+    \bTD \getspr{100} \eTD \bTD test \setspr{30} \eTD
+  \eTR
+  \bTR
+    \bTD \getspr{20} \eTD \bTD \getspr{4+3} \eTD
+  \eTR
+  \bTR
+    \bTD \getspr{A[1] + A[2]} \eTD
+    \bTD \getspr{B1 + B2} \eTD
+  \eTR
+  \bTR
+    \bTD[nx=2] \bf \getspr{(A[3] + B[3]) /100} \eTD
+  \eTR
+  \bTR
+    \bTD[nx=2] \bf \getspr{fmt("@0.3f",(A[3] + B[3]) /100)} \eTD
+  \eTR
+  \bTR
+    \bTD[nx=2] \bf \getspr{fmt("@0.3f",(sum(A,1,2)) / 10)} \eTD
+  \eTR
+\eTABLE
+\stopbuffer
+
+\typebuffer[demo]
+
+The method to use depends on the complexity of the table. If there is
+more text than data then this method is probably more comfortable.
+
+\placefigure
+  [here]
+  [spreadsheet:3]
+  {A sheet can be filled and accessed from regular tables.}
+  {\getbuffer[demo]}
+
+% \setupspreadsheet[mysheet]
+%
+% \startspreadsheet[mysheet]
+%
+% \bTABLE[align=middle]
+%   \bTR
+%     \bTD \getspr{100} \eTD \bTD test \setspr{30} \eTD
+%   \eTR
+%   \bTR
+%     \bTD \getspr{20} \eTD \bTD \getspr{4+3.5} \eTD
+%   \eTR
+%   \bTR
+%     \bTD \getspr{A[1] + A[2]} \eTD
+%     \bTD \getspr{B[1] + B[2]} \eTD
+%   \eTR
+%   \bTR
+%     \bTD[nx=2] \bf \getspr{A[3] + B[3]} \eTD
+%   \eTR
+% \eTABLE
+%
+% \stopspreadsheet
+
+\stopsection
+
+\startsection[title={A few settings}]
+
+It's possible to influence the rendering. The following example demonstrates
+this. We don't use any formatting directives.
+
+\startbuffer[demo]
+\startspreadsheettable[test]
+  \startrow
+    \startcell   123456.78 \stopcell
+  \stoprow
+  \startrow
+    \startcell  1234567.89 \stopcell
+  \stoprow
+  \startrow
+    \startcell A[1] + A[2] \stopcell
+  \stoprow
+\stopspreadsheettable
+\stopbuffer
+
+\typebuffer[demo]
+
+\placefigure
+  [here]
+  [spreadsheet:4]
+  {Formatting (large) numbers.}
+  {\getbuffer[demo]}
+
+\in {Figure} [spreadsheet:4] demonstrates how this gets rendered by
+default. However, often you want numbers to be split in parts separated by
+periods and commas. This can be done as follows:
+
+\startbuffer[setup]
+\definehighlight[BoldAndRed]  [style=bold,color=darkred]
+\definehighlight[BoldAndGreen][style=bold,color=darkgreen]
+
+\setupspreadsheet
+  [test]
+  [period={\BoldAndRed{.}},
+   comma={\BoldAndGreen{,}},
+   split=yes]
+\stopbuffer
+
+\typebuffer[setup] \getbuffer[setup]
+
+\placefigure
+  [here]
+  [spreadsheet:5]
+  {Formatting (large) numbers with style and color.}
+  {\getbuffer[setup,demo]}
+
+\stopsection
+
+\startsection[title={The \LUA\ end}]
+
+You can also use spreadsheets from within \LUA. The following example is
+rather straightforward:
+
+\startbuffer[demo-a]
+\startluacode
+context.startspreadsheettable { "test" }
+  context.startrow()
+    context.startcell() context("123456.78")   context.stopcell()
+  context.stoprow()
+  context.startrow()
+    context.startcell() context("1234567.89")  context.stopcell()
+  context.stoprow()
+  context.startrow()
+    context.startcell() context("A[1] + A[2]") context.stopcell()
+  context.stoprow()
+context.stopspreadsheettable()
+\stopluacode
+\stopbuffer
+
+\typebuffer[demo-a]
+
+However, even more \LUA|-|ish is the next variant:
+
+\startbuffer[demo-b]
+\startluacode
+  local set = moduledata.spreadsheets.set
+  local get = moduledata.spreadsheets.get
+
+  moduledata.spreadsheets.start("test")
+    set("test",1,1,"123456.78")
+    set("test",2,1,"1234567.89")
+    set("test",3,1,"A[1] + A[2]")
+  moduledata.spreadsheets.stop()
+
+  context.bTABLE()
+    context.bTR()
+      context.bTD() context(get("test",1,1)) context.eTD()
+    context.eTR()
+    context.bTR()
+      context.bTD() context(get("test",2,1)) context.eTD()
+    context.eTR()
+    context.bTR()
+      context.bTD() context(get("test",3,1)) context.eTD()
+    context.eTR()
+  context.eTABLE()
+\stopluacode
+\stopbuffer
+
+\typebuffer[demo-b]
+
+Of course the second variant does not make much sense as we can do this way
+more efficient by not using a spreadsheet at all:
+
+\startbuffer[demo-c]
+\startluacode
+  local A1, A2 = 123456.78, 1234567.89
+  context.bTABLE()
+    context.bTR()
+      context.bTD() context(A1)    context.eTD()
+    context.eTR()
+    context.bTR()
+      context.bTD() context(A2)    context.eTD()
+    context.eTR()
+    context.bTR()
+      context.bTD() context(A1+A2) context.eTD()
+    context.eTR()
+  context.eTABLE()
+\stopluacode
+\stopbuffer
+
+\typebuffer[demo-c]
+
+You can of course use format explicitly. Here we use the normal percent
+directives because we're in \LUA, and not in \TEX, where percentage
+signs are a bit of an issue.
+
+\startbuffer[demo-d]
+\startluacode
+  local A1, A2 = 123456.78, 1234567.89
+  local options = { align = "flushright" }
+  context.bTABLE()
+    context.bTR()
+      context.bTD(options)
+        context("%0.2f",A1)
+      context.eTD()
+    context.eTR()
+    context.bTR()
+      context.bTD(options)
+        context("%0.2f",A2)
+      context.eTD()
+    context.eTR()
+    context.bTR()
+      context.bTD(options)
+        context("%0.2f",A1+A2)
+      context.eTD()
+    context.eTR()
+  context.eTABLE()
+\stopluacode
+\stopbuffer
+
+\typebuffer[demo-d]
+
+As expected and shown in \in {figure} [spreadsheet:6], only the first and last
+variant gets the numbers typeset nicely.
+
+\placefigure
+  [here]
+  [spreadsheet:6]
+  {Spreadsheets purely done as \CONTEXT\ \LUA\ Document.}
+  {\startcombination[4*1]
+     {\getbuffer[demo-a]} {}
+     {\getbuffer[demo-b]} {}
+     {\getbuffer[demo-c]} {}
+     {\getbuffer[demo-d]} {}
+   \stopcombination}
+
+\stopsection
+
+\startsection[title={Helper macros}]
+
+There are two helper macros that you can use to see what is stored in a
+spreadsheet:
+
+\starttyping
+\inspectspreadsheet[test]
+\showspreadsheet   [test]
+\stoptyping
+
+The first command reports the content of \type {test} to the console, and
+the second one typesets it in the running text:
+
+\blank
+\showspreadsheet[test]
+\blank
+
+Another helper function is \type {\doifelsespreadsheetcell}, You can use this
+one to check if a cell is set.
+
+\startbuffer[demo]
+(1,1): \doifelsespreadsheetcell[test]{1}{1}{set}{unset}
+(2,2): \doifelsespreadsheetcell[test]{2}{2}{set}{unset}
+(9,9): \doifelsespreadsheetcell[test]{9}{9}{set}{unset}
+\stopbuffer
+
+\typebuffer[demo]
+
+This gives:
+
+\startlines
+\getbuffer[demo]
+\stoplines
+
+There is not much more to say about this module, apart from that it is a
+nice example of a \TEX\ and \LUA\ mix. Maybe some more (basic) functionality
+will be added in the future but it all depends on usage.
+
+\stopsection
+
+\startsubject[title={Colofon}]
+
+\starttabulate[|B|p|]
+\NC author    \NC \getvariable{document}{author}, \getvariable{document}{affiliation}, \getvariable{document}{location} \NC \NR
+\NC version   \NC \currentdate \NC \NR
+\NC website   \NC \getvariable{document}{website} \endash\ \getvariable{document}{support} \NC \NR
+\NC copyright \NC \symbol[cc][cc-by-sa-nc] \NC \NR
+\stoptabulate
+
+\stopsubject
+
+\stopdocument