%D \module
%D   [      file=s-pre-09,
%D        version=unknown,
%D          title=\CONTEXT\ Style File,
%D       subtitle=Presentation Environment 9,
%D         author=Hans Hagen,
%D           date=\currentdate,
%D      copyright={PRAGMA / Hans Hagen \& Ton Otten}]
%C
%C This module is part of the \CONTEXT\ macro||package and is
%C therefore copyrighted by \PRAGMA. See mreadme.pdf for
%C details.

%D I made this style when I had to give a presentation on
%D the \MAPS\ bibliography production for several user group
%D meetings. This style is rather tuned for combinations of
%D examples and explanations. The colors match the \MAPS\
%D bibliography colors.

\startmode[asintended] \setupbodyfont[lbr] \stopmode

\setupbodyfont[14.4pt]

%D A couple of years later, in 2001 this style was documented
%D and made public. While documenting, I also changed box
%D building on top of overlays into the now available layer
%D positioning. So, this styles demonstrates quite some
%D tricks.

\setuppapersize
  [S6][S6]

\setuplayout
  [topspace=0cm,
   backspace=0cm,
   header=0pt,
   footer=0pt,
   width=middle,
   height=middle]

%D Local environments can be set by using the setups commands.
%D For downward compatibility, we keep supporting the \type
%D {\...Settings} hooks. Using local environments is seldom
%D needed.

\let\TextSettings  \empty
\let\SampleSettings\empty

\startsetups [text]   \TextSettings   \stopsetups
\startsetups [sample] \SampleSettings \stopsetups

%D The dimensions are kind of fixed.

\def\FrameWidth  {448pt}
\def\FrameHeight {348pt}
\def\FrameOffset {24pt}
\def\FrameSkip   {12pt}

%D But they {\em can} and {\em will} be changed.

\def\FrameWidth  {408pt}
\def\FrameHeight {318pt}

%D The funny values come from the $3:4$ display aspect
%D ratio.

\setupcolors
  [state=start]

\definecolor[PageColor]       [s=.40]
\definecolor[TextColor]       [s=.90]
\definecolor[InteractionColor][r=.40]
\definecolor[LineColor]       [r=.60,g=.60]

%D Of course we go interactive and since we will probably
%D open other documents, we make sure that the viewer opens a
%D new window.

\setupinteraction
  [color=InteractionColor,
   contrastcolor=LineColor,
   display=new,
   state=start]

\setupinteractionscreen
  [option=max]

%D Before we come to the real macros, we do a little bit of
%D tuning.

\setupitemize
  [1][packed]

\setuptyping
  [blank=medium]

%D Apart from the titlepage, the page gets a simple colored
%D background. Later we will activate the background.

\setupbackgrounds
  [page]
  [backgroundcolor=PageColor]

%D Everything gets frames by a nice \METAPOST\ frame.

\defineoverlay [background] [\uniqueMPgraphic{background}]

\startuniqueMPgraphic{background}
  path p ; color c, w, d ;
  c := \MPcolor{PageColor} ;
  w := \MPcolor{TextColor} ;
  d := \MPcolor{LineColor} ;
  p := unitsquare xscaled OverlayWidth yscaled OverlayHeight ;
  pickup pencircle scaled (1.5*\FrameSkip) ;
  draw p withcolor c ;
  pickup pencircle scaled \FrameSkip ;
  fill p withcolor w ;
  draw p withcolor d ;
\stopuniqueMPgraphic

%D We will present samples and explanation pair||wise, so
%D we need a hyperlink that skips a page.

\defineoverlay [nextpage]     [\overlaybutton{nextpage}]
\defineoverlay [previouspage] [\overlaybutton{previouspage}]
\defineoverlay [skippage]     [\overlaybutton{page(+2)}]

%D Layers are normally used to position multiple content on
%D a specific overlay. Here we will use them to position
%D only and since the samples and text will swap place, we
%D will use quite a few layers.

\defineoverlay [text]   [\composedlayer{text}]
\defineoverlay [sample] [\composedlayer{sample}]
\defineoverlay [common] [\composedlayer{common}]

%D There are three positions. When combined, the sample and
%D text windows overlap, otherwise the lone window is
%D centered. We could have used one layer and reversed the
%D order by setting the \type {direction} parameter, but
%D this approach is more readable.

\definelayer
  [text]
  [x=\makeupwidth,y=\makeupheight,location=lt,
   hoffset=-\FrameSkip,voffset=-\FrameSkip]

\definelayer
  [sample]
  [hoffset=\FrameSkip,voffset=\FrameSkip]

\definelayer
  [common]
  [x=.5\makeupwidth,y=.5\makeupheight,location=c]

%D The topic is put in the lower right corner of the text
%D window.

\defineoverlay [topic] [\composedlayer{topic}]

\definelayer
  [topic]
  [x=\FrameWidth,y=\FrameHeight,location=lt,
   hoffset=-\FrameOffset,voffset=-\FrameSkip]

%D The topic is put in a framed box. That way we can make
%D sure that it gets a background, which looks better when
%D it covers something else. Otherwise we could have stuct
%D to:
%D
%D \starttyping
%D \def\Topic#1%
%D   {\setlayer[topic]{\color[PageColor]{\bfb\setstrut#1}}}
%D \stoptyping
%D
%D But, we go for the nice alternative:

\def\Topic#1%
  {\doifsomething{#1}
     {\setlayer [topic]
        {\bfb\setstrut
         \inframed
           [frame=off,foregroundcolor=PageColor,offset=0pt,
            background=color,backgroundcolor=TextColor]
           {#1}}}}

%D The sample as well as the explanation will be collected in
%D a buffer. That way we can reuse the content. We could
%D have used a box instead, but can we be sure that the content
%D is not adapting itself? So, buffers we use.

\resetbuffer[sample]
\resetbuffer[text]

%D Both the sample and explanation are kind of windowed.

\defineframedtext
  [SampleText]
  [width=\FrameWidth,height=\FrameHeight,offset=\FrameOffset,
   frame=off,align=normal,strut=no,before=,after=,
   background={background,nextpage}]

%D We safe some keying in by combining things in one macro.

\def\DoSampleText#1#2#3% kind layer overlays
  {\setupframedtexts[SampleText][background={background,#3}]
   \setlayer[#2]
     {\startSampleText[none]
        \setups[#1]
        \getbuffer[#1]
      \stopSampleText}}

\def\StartSample{\dostartbuffer[sample][StartSample][StopSample]}
\def\StartText  {\dostartbuffer[text]  [StartText]  [StopText]}

%D The following definitions apply at the outer level.

\def\StopSample
  {\startstandardmakeup
     \DoSampleText{sample}{common}{nextpage}
   \stopstandardmakeup
   \resetbuffer[sample]}

\def\StopText
  {\startstandardmakeup
     \DoSampleText{text}{common}{topic,nextpage}
   \stopstandardmakeup
   \resetbuffer[text]}

\setupbackgrounds[page][background={color,nextpage}]
\setupbackgrounds[text][background=common]

%D When we combine sample and text, we get slightly
%D different definitions. As you can see we generate two
%D pages. Watch how we manipulate the order of the
%D overlays and teh nature of the buttons. Here data
%D abstraction really pays off.

\def\StartIdea
  {\bgroup
   \let\StopSample\relax
   \let\StopText  \relax}

\def\StopIdea%
  {\setupbackgrounds[page][background={color,skippage}]
   \setupbackgrounds[text][background={text,sample}]
   \startstandardmakeup
     \DoSampleText{sample}{sample}{previouspage}
     \DoSampleText{text}  {text}  {topic,nextpage}
   \stopstandardmakeup
   \setupbackgrounds[page][background={color,nextpage}]
   \setupbackgrounds[text][background={sample,text}]
   \startstandardmakeup
     \DoSampleText{sample}{sample}{previouspage}
     \DoSampleText{text}  {text}  {topic,nextpage}
   \stopstandardmakeup
   \egroup}

%D The rest of the definitions takes care of the title page.
%D Please don't steal this one for your own documents.

\defineoverlay[joke] [\useMPgraphic{joke}{n=0}] % not to be changed!

\startuseMPgraphic{joke}{n}
  StartPage ;
  path p, q ; numeric w ; pair xy ;
  set_grid(OverlayWidth,OverlayHeight,OverlayWidth/8,OverlayHeight/8) ;
  if \MPvar{n}=1 :
    p := fulldiamond ; fill Page withcolor \MPcolor{TextColor} ;
  else :
    p := fullsquare  ; fill Page withcolor \MPcolor{PageColor} ;
  fi ;
  forever :
    xy := center Page randomized (OverlayWidth,OverlayHeight) ;
    if new_on_grid(xpart xy, ypart xy) :
      q := (p xyscaled (OverlayWidth/5,OverlayHeight/5))
           randomized (\FrameSkip,\FrameSkip)
           shifted xy ;
      w := (\FrameSkip) randomized (\FrameSkip/2) ;
      draw q withcolor \MPcolor{PageColor} withpen pencircle scaled (1.5w) ;
      fill q withcolor \MPcolor{TextColor} ;
      draw q withcolor \MPcolor{LineColor} withpen pencircle scaled (   w) ;
    fi ;
    exitif grid_full ;
  endfor ;
  StopPage ;
\stopuseMPgraphic

\defineoverlay[fuzzy][\useMPgraphic{fuzzy}]

\startuseMPgraphic{fuzzy}
  path p ; numeric w ;
  p := (fullsquare xyscaled (OverlayWidth,OverlayHeight))
       randomized (\FrameSkip,\FrameSkip) ;
  w := (\FrameSkip) randomized (\FrameSkip/2) ;
  draw p withcolor \MPcolor{PageColor} withpen pencircle scaled (1.5w) ;
  fill p withcolor \MPcolor{TextColor} ;
  draw p withcolor \MPcolor{LineColor} withpen pencircle scaled (   w) ;
\stopuseMPgraphic

%D This time we use a fit window, but with a slightly randomized
%D frame, our trademark so to say.

\def\StartTitlePage
  {\bgroup
   \setupbackgrounds[page][background={joke,nextpage}]
   \startstandardmakeup
   \switchtobodyfont[big]
   \setupframedtexts
     [SampleText]
     [background=fuzzy,
      foregroundcolor=PageColor,
      width=fit,
      height=fit,
      align=middle]
   \startSampleText[middle]
   \bfd\setupinterlinespace
   \def\\{\bfb\setupinterlinespace\vfil\def\\{\vfil}}}

\def\StopTitlePage
  {\stopSampleText
   \stopstandardmakeup
   \egroup}

\def\TitlePage#1%
  {\StartTitlePage#1\StopTitlePage}

%D Let's nill some error prone presentation macros.

\let\Subject  \Topic
\let\Topics   \gobbleoneargument
\let\Subjects \relax

%D We will avoid \quote {overfull} messages.

\dontcomplain

\doifnotmode{demo}{\endinput}

%D The (rather silly) demo section.

\starttext

\setupbodyfont[12pt]

\TitlePage{Quotes, Quotes\\and more quotes}

\StartIdea
  \StartSample
    \input knuth \par
  \StopSample
  \StartText
    \Topic{Tufte}
    \input tufte \par
  \StopText
 \StopIdea

\StartIdea
  \StartSample
    \input materie \par
  \StopSample
  \StartText
    \input reich   \par
  \StopText
\StopIdea

\StartText
  \input tufte \par
\StopText

\StartIdea
  \StartSample
    \input knuth \par
  \StopSample
  \StartText
    \input tufte \par
  \StopText
\StopIdea

\stoptext