Re: table and MPpositiongraphic

[Hans Hagen <pragma@wxs.nl>]

Hi Patrick,

>while browsing thru the source and trying some examples, I can't
>sensible output of the following code. (No MP stuff is visible)

right, this is because it's old crappy code; and so you got me in debugging 
mode again

\setupcolors[state=start]

\starttext

\def\cw#1{\color[white]{#1}}

\startMPpositiongraphic{tableshade}
   initialize_area(\MPpos{\MPvar{from}},\MPpos{\MPvar{to}}) ;
   color c ; c := \MPvar{color} ;
   linear_shade(pxy,0,.4c,.9c) ;
   anchor_area(\MPanchor{\MPvar{from}}) ;
\stopMPpositiongraphic

\setMPpositiongraphic{b:x}{tableshade}{from=b:x,to=e:x,color=red}
\setMPpositiongraphic{b:y}{tableshade}{from=b:y,to=e:y,color=green}
\setMPpositiongraphic{b:z}{tableshade}{from=b:z,to=e:z,color=blue}

\starttable[|c|c|c|]
\GFC[b:z] \cw{this is a small}  \NC       \cw{table}            \NC     in 
which we      \NC \FR
\NC       \cw{will demonstrate} \GFC[c:y] \cw{that this}        \GTC[c] 
\cw{positioning} \NC \MR
\GSC[a:x] \cw{mechanism also}   \GTC[b]   \cw{works quite well} \NC     in 
tables        \NC \LR
\stoptable

\stoptext

so, \startMPpositiongraphic is now named and handles vars

btw, i leave it to you to figure out the \XC alternative (which is a nicer 
way of coding)

there are a few more places where this kind of old code shows up (which is 
one reason why it's in the comments and not in manuals); last week i fixed 
something in a presentation style -) This kind of code is now reaching a 
more stable state because it's quite extensively used in some of the 
projects that we're involved in (i can show you some of the coding in 
bremen if you're interested; this kind of things is needed to make dtp 
competing/beating styles and it's a slow process to make the mechanisms 
programmable and the code readable)

btw, the textbackground features work ok in tables as well, so in a way 
this kind of things are no longer needed, unless you want to span cells in 
complicated ways

Hans
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                                   Hans Hagen | PRAGMA ADE | pragma@wxs.nl
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