Re: [NTG-context] Colored labels with MetaPost in MkII

28 Oct 2008

      On Mon, 27 Oct 2008, Wolfgang Schuster wrote:
...
On Fri, Oct 24, 2008 at 2:15 PM, Aditya Mahajan  wrote:
...
On Fri, 24 Oct 2008, Wolfgang Schuster wrote:
...
Hi all,
what is the best method to format MetaPost labels in MkII with \doattributes.
\startMPenvironment[global]
...
\setupcolors[state=start]
\def\labelstyle{bold}
\def\labelcolor{red}
\stopMPenvironment
This gives you only bold label.
...
\starttext
\startMPcode
label(textext("\doattributes{label}{style}{color}{Label}"),origin) ;
\stopMPcode
\stoptext
Tex colors do not work inside textext. Try
label(textext("\startcolor[red] red \stopcolor"), origin) ;
One way to get around this is to use \sometxt.
label(\sometxt{\doattributes{label}{style}{color}{Label}},(5cm,0)) ;
But then you have to be careful about the differences between \sometxt in
MKII and MKIV (which I need to  summarize on the wiki).
Here is a new example where I can't even use \sometxt.
Sometxt does not work appear to work with \startMPdrawing (there is 
no output at all). I think that the reason is that MPdrawing simply writes 
stuff to the MPfile without doing the extra work needed for sometxt.

I will call this is a bug, but I do not know if Hans wants to work on 
TeX-MP interaction in MKII now.
...
\setupcolors[state=start]
\def\labelstyle{bold}
\def\labelcolor{red}
\starttext
\resetMPdrawing
\startMPdrawing
label(textext("\doattributes{label}{style}{color}{Label}"),origin) ;
label(\sometxt{\doattributes{label}{style}{color}{Label}},origin) ;
\stopMPdrawing
\MPdrawingdonetrue
\getMPdrawing
\stoptext
It may be possible to write your macros without \start-stop-MPdrawing. 
Everything inside \start-stop MP(code|graphic) is first parsed by TeX, so 
you can do things like

\newif\ifcircle \circletrue

\startMPcode
draw \ifcircle fullcircle \else fullsquare \fi xyscaled (5cm,5cm) ;
\stopMPcode

So, instead of writing stuff to MP using start-stop MPdrawing, you can 
simply set some flags in conditionals and chardefs, and then write one 
MP(graphic|code) to write one MP file. This strategy will not work for all 
cases, but can be useful for some.

Aditya