Rik Kabel via ntg-context schrieb am 26.09.2021 um 22:13:

Hello list mavens,

What are the circumstances under which style=italicface should be used instead of style=italic. I note a difference when I define highlighting. I expected to see no difference in the line before and line after the hairline the example below, but see that italicface adapts to nesting, while italic does not:

Are there other places where this makes a difference?

\setupbodyfontenvironment
      [default]
        [em=italicface] %same with italic for this example
\definehighlight
        [emIt]
        [style=italic]
\definehighlight
        [emIf]
        [style=italicface]
\definehighlight
        [emEm]
        [style=\em]

\starttext

{\em abc {\em def} ghi}: \type{\em}

\emph{abc {\emph def} ghi}: \type{\emph}

\emEm{abc {\emEm def} ghi}: \type{\emEm \definehighlight[style=\em]}

\emIf{abc {\emIf def} ghi}: \type{\emIf \definehighlight[style=italicface]}

\hairline

\emIt{abc {\emIt def} ghi}: \type{\emIt \definehighlight[style=italic]}

\stoptext

The \em command has two special values which are allowed when you change the style with

\setupbodyfontenvironment[default][em=...]

with the value "slanted" and "italic". When you choose one of them the result depends on the current weight (\tf or \bf) but with every other value you're just using whatever the style command/name provides.

When you pass "italicface" you're using a style which uses either \it or \bi dependant on the current weight. The result from the "italic" value doesn't depend on the behavior or the normal italic style (\it) which is the reason why you get different result when you use \em compared with \it.

Example:

\starttext

\tex{it}: normal {\it italic} {\bf bold {\it italic}}

\tex{italicface}: normal {\italicface italic} {\bf bold {\italicface italic}}

\tex{em}: normal {\em italic} {\bf bold {\em italic}}

\stoptext

Wolfgang