Re: tweaking underlining

[Hans Hagen <pragma@wxs.nl>]

Stuart Jansen wrote:
> Reading the list archives, it looks like there are certain advantages,
> to performing underlining according to my example below:
> 
> =====
> \setupcolors[state=start]
> \definetextbackground[underline][location=text,alternative=1,background=,frame=off]
> \definestartstop
>   [underline]
>   [before={\starttextbackground[underline]},
>    after=\stoptextbackground]
> \starttext
> \startunderline{}http://gurulabs.com/\stopunderline
> \stoptext
> =====
> 
> I would like to tweak this a little however. Specifically, I'd like to
> change the color of the line and move it down a point or two.
> 
> In one thread, Hans hinted how to do this:
> 
> 
>>you can redefine the metapost graphic, the main thing there is that
>>you draw/fill something related to the multipar paths; it takes a bit
>>of experimenting, but after a while you start seeing possibilities. 
>>See plus-rul.tex for an example of such a graphic.
> 
> 
> I think I've tracked this reference down to the definition of
> mpos:par:columnset, but at this point am lost as to how to proceed.
> Metapost is still beyond me. Any hints would be much appreciated.

ok, a quick hack (no time today):

the one ou need to tweak is:

\startuseMPgraphic{mpos:par:columnset}
   \iftracepositions show_multi_pars \else draw_multi_pars \fi ;
\stopuseMPgraphic

so one option is to provide your own draw macro (the draw macro is in 
mp-core.mp); however, here you can check a bit:

\startuseMPgraphic{mpos:par:columnset}
   \iftracepositions show_multi_pars \else draw_multi_pars \fi ;
   path p ; p := boundingbox currentpicture ;
   currentpicture := currentpicture shifted (0,-3pt) ;
   setbounds currentpicture to p ;
\stopuseMPgraphic

or better:

\startuseMPgraphic{mpos:par:columnset}
   \iftracepositions show_multi_pars \else draw_multi_pars \fi ;
   path p ; p := boundingbox currentpicture ;
   currentpicture := currentpicture shifted (0,-StrutDepth/2) ;
   setbounds currentpicture to p ;
\stopuseMPgraphic

(remind me some time later to add an option to shift the thing down by keyword 
control)

[this is wikiable]

Hans


-----------------------------------------------------------------
                                           Hans Hagen | PRAGMA ADE
               Ridderstraat 27 | 8061 GH Hasselt | The Netherlands
      tel: 038 477 53 69 | fax: 038 477 53 74 | www.pragma-ade.com
                                              | www.pragma-pod.nl
-----------------------------------------------------------------