[NTG-context] Vertical alignment of marginal material

23 Feb 2004

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Message: 12
Date: Mon, 23 Feb 2004 10:14:38 +0100
To: ntg-context@ntg.nl
From: Hans Hagen 
Subject: Re: [NTG-context] alignment of marginal material
Reply-To: ntg-context@ntg.nl
At 21:40 22/02/2004, Jonathan Nicholl wrote:
...
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I am trying to write a macro which places a picture in the margin. I  
would
like the centre of the picture to be aligned vertically with the  
centre of
the paragraph in which I call the macro. The following works in  
simple cases:
\def\hazard#1{%
        \setbox0=\vbox{#1}%
        \inleft [low] {%
                \framed%
                        [height=\ht0,%
                        top=\vss,%
                        bottom=\vss,%
                        frame=off]%
                        {\externalfigure [sharp turn sign]}%
                }%
        #1}%
If I type something like
\hazard{…paragraph text…}
this produces what I want. But it breaks down with mathematics.
\hazard{%
        \startformula
                …mathematics…
        \stopformula
}
produces the picture aligned with the bottom of the mathematics.
A solution to this problem escapes me. Can anyone suggest an improved  
macro?
Here is my 10 minute solution ... if i'm in the mood i can make an  
option of it
Maybe other people would like some support for this kind of thing.  
Certainly I would find it useful if, when I wrote `\inmargin…'  
somewhere inside a paragraph, I could specify an option to determine  
the vertical alignment of the marginal material. Suppose `top' aligned  
the top of the marginal material with the top of the paragraph, `mid'  
the middle of the marginal material with the midpoint of the paragraph,  
and `bot'  the bottom of the marginal material with the bottom of the  
paragraph. That would be good.
...
\newcounter\CurrentFigPar
\def\StartFigPar#1%
   {\doglobal\increment\CurrentFigPar
    \placefigure
      [leftmargin,line,none]{}
      {\setbox\scratchbox\hbox{#1}%
\ifnum\MPp{figpar:b:\CurrentFigPar}=\MPp{figpar:e: 
\CurrentFigPar}\relax
         \scratchdimen\MPy{figpar:b:\CurrentFigPar}%
         \advance\scratchdimen-\MPy{figpar:e:\CurrentFigPar}%
         \advance\scratchdimen-\ht\scratchbox
         \advance\scratchdimen\lineheight
       \else
         \scratchdimen\zeropoint
       \fi
       \vbox{\vskip.5\scratchdimen\box\scratchbox}}%
    \indent\hpos{figpar:b:\CurrentFigPar}{\strut}\ignorespaces}
\def\StopFigPar
{\removeunwantedspaces\hpos{figpar:e:\CurrentFigPar}{\strut}\endgraf}
\starttext
\input tufte
\StartFigPar{\externalfigure[cow.pdf][width=1cm]} \input tufte  
\StopFigPar
\input tufte
\stoptext=20
Thank you very much indeed, Hans. This puts cow.pdf in the right place  
in the margin. One problem remains. Surrounding a paragraph by  
\StartFigPar…\StopFigPar often messes up the inter-paragraph vertical  
spacing. In particular, surrounding \startformula…\stopformula by  
\StartFigPar…\StopFigPar introduces big spaces above and below the  
mathematics.

Is there a simple way to stop this? It would be good if introducing a  
few \StartFigPar…\StopFigPar pairs to a document had no effect at all  
on the main body of the document, and just put figures in the margin.

-----------------------

Jonathan Nicholl
Department of Philosophy
King's College London