Re: how to color italics?

[Hans Hagen <pragma@wxs.nl>]

Taco Hoekwater wrote:
> 
> Aditya Mahajan wrote:
>> Ah, so that is why it is lowlevel. I wonder why the following does not 
>> work.
>>
>> \setupbodyfontenvironment [default]
>>                            [em={\italic\color[red]}]
> 
> The em key is a bit extra extra special: it has to be either
> 'italic' or 'slanted', everything else is ignored. This is because
> of the need to allow bold emphasis. (\bf\em == \bs or \bi).
> 
> I would personally be happier if it would just use whatever was
> in the argument when it is *not* italic or slanted, instead of
> ignoring the argument, but that's how it is.


\def\doemphasistypeface#1#2%
   {\doifelsevalue{\??ft\fontclass\normalizedbodyfontsize\c!em}\v!slanted
      {#1}%
      {\doifelsevalue{\??ft\fontclass\normalizedbodyfontsize\c!em}\v!italic
         {#2}%
         {\doifelsevaluenothing{\??ft\fontclass\normalizedbodyfontsize\c!em}
            {\doifelsevalue{\??ft\normalizedbodyfontsize\c!em}\v!slanted
               {#1}%
               {\doifelsevalue{\??ft\normalizedbodyfontsize\c!em}\v!italic
                  {#2}%
                  {\getvalue{\??ft\normalizedbodyfontsize\c!em}}}}
            {\getvalue{\??ft\fontclass\normalizedbodyfontsize\c!em}}}}}

however, this does not provide italic correction, so better is:

\newtoks\everyemphasized

\unexpanded\def\em
   {\relax
    \ifdim\slantperpoint>\zeropoint
      \settrue\emneeded
    \else
      \setfalse\emneeded
    \fi
    \setemphasisboldface % new
    \ifx\fontalternative\c!it      % \ifnum\fam=\itfam
      \def\emphasistypeface{\it}\tf
    \else\ifx\fontalternative\c!sl % \ifnum\fam=\slfam
      \def\emphasistypeface{\sl}\tf
    \else\ifx\fontalternative\c!bf % \ifnum\fam=\bffam
      \emphasisboldface
    \else\ifx\fontalternative\c!bs % \ifnum\fam=\bsfam
      \def\emphasisboldface{\bs}\bf
    \else\ifx\fontalternative\c!bi % \ifnum\fam=\bifam
      \def\emphasisboldface{\bi}\bf
    \else
      \emphasistypeface
    \fi\fi\fi\fi\fi
    \the\everyemphasized
    \ifconditional\emneeded\relax
    \else
      \expandafter\aftergroup
    \fi
    \emphasiscorrection}

which provides a hook, as in:


\appendtoks
     \red
\to \everyemphasized


both mechanisms will be provided (maybe something emcolor later, when i 
can get myself motivated for such an possibly never documented feature)

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                                           Hans Hagen | PRAGMA ADE
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