Setting up a typeface

["Ulrich Dirr" <ud@art-satz.de>]

Hi,

I've now studied the docs for a while and experimenting with a bunch of
settings but I'm still failing setting up typefaces correctly in ConTeXt.
Probably the font mechanism in ConTeXt is much more elaborate than with
LaTeX's NFSS. But I'm too stupid to understand it :-( Could someone please
help me?

My test case -- and it will be the sans serif part of my wish list --
should setup the Linotype HelveticaNeue as body font. The main part is not
very difficult to achieve.

The test file:
-------------------------------------------------------------------------
\setupoutput [pdftex]
\input pdftexconfig
\usetypescriptfile [type-NeueHelvetica]
\usetypescript[HelveticaNeue][ec]
\setupbodyfont[HelveticaNeueLT,ss,10pt]
\starttext
\showbodyfontenvironment[HelveticaNeueLT]
\showbodyfont[HelveticaNeueLT]
\stoptext
-------------------------------------------------------------------------

type-NeueHelvetica.tex:
-------------------------------------------------------------------------
\starttypescript [sans] [HelveticaNeue] [name]
\definefontsynonym [Sans]                 [HelveticaNeueLT-Roman]
\definefontsynonym [SansItalic]           [HelveticaNeueLT-Italic]
\definefontsynonym [SansBold]             [HelveticaNeueLT-Bold]
\definefontsynonym [SansBoldItalic]       [HelveticaNeueLT-BoldItalic]   
[...]
\stoptypescript

\starttypescript [sans] [HelveticaNeue] [ec]
\definefontsynonym [HelveticaNeueLT-Roman]      [lhnr8t]  [encoding=ec]
\definefontsynonym [HelveticaNeueLT-Italic]     [lhnri8t] [encoding=ec]
\definefontsynonym [HelveticaNeueLT-Bold]       [lhnb8t]  [encoding=ec]
\definefontsynonym [HelveticaNeueLT-BoldItalic] [lhnbi8t] [encoding=ec]
[...]
\stoptypescript

\starttypescript [HelveticaNeue][ec]
\usetypescript [sans] [HelveticaNeue] [name]
\usetypescript [sans] [HelveticaNeue] [size]
\stoptypescript

\starttypescript [HelveticaNeue] [ec]
\definetypeface [HelveticaNeueLT] [ss] [sans] [HelveticaNeue] [default]
[encoding=ec]
\stoptypescript
-------------------------------------------------------------------------

The next step should define destinct sizes for use in a project. And here
I'm always failing.

I've tried, e.g.,
\definebodyfontenvironment
  [9bp]
  [       text=9bp,
        script=7bp,
  scriptscript=5bp,
             x=7bp,
            xx=5bp,
           big=11bp,
         small=7bp,
  interlinespace=11bp]
or, e.g.,
\starttypescript [sans] [HelveticaNeue] [size]
\definebodyfont [10bp] [ss]
  [tf=Sans at 10bp,
   bf=SansBold,
   it=SansItalic,
   sl=SansItalic,
   bi=SansBoldItalic,
   bs=SansBoldItalic]
\stoptypescript

in all sizes I want, with and without definitions of \definebodyfont, but
never got what I want. 

How can I setup my typeface (regular, bold, etc.) to use the specific sizes
5,6,7,8,9.5,10,12,14,18,24,28 *bp*??? (And with correct dependencies)

I'm definitely not understanding how the general scheme works. And all
examples I've found always use the standard font sizes and the standard
measurement units.

Please help me!

Best regards,
Ulrich Dirr

P.S. are there predefined shortcuts for heavy, light, etc. variants?