> Meer, Hans van der <mailto:H.vanderMeer@uva.nl>
> 14. Mai 2016 um 21:13
> I think I did not state the problem clear enough.
> The solution given here supposes that the fontsize is known beforehand.
> However, what I am doing is calculating a font size based on the 
> current one and than switch to that size.
> It is part of a fontsize changing mechanism inside an xmlsetup. In 
> short what I am doing is:
>
> \scratchdimen=\the\dimexpr\bodyfontsize\relax
> \advance\scratchdimen 'somevalue' \relax
> %\definebodyfontenvironment[\the\scratchdimen]
> \begingroup
> % must keep the change local
> \switchtobodyfont[\the\scratchdimen]
> ...
> \endgroup
>
> The commented out \definebodyfontenvironment kills a lot of the font 
> messages but I fear that each the time the same work is done as 
> without it. The only benefit being the suppression of the font 
> messages in the log ;-)
>
> It might be impossible to accomplish this efficiently -- that is 
> execute the font calculations once only for the given size. But at 
> least I would like to give it a try.
>
You can save time with the \definebodyfontenvironment command.

In the following example context has to create a new bodyfont
environment for each iteration (because the values are local
to the group) to calculate the a, b, c etc. sizes which takes time
but in the same loop context only has to load the predefined size.

\starttext

\testfeatureonce{1000}
   {\begingroup
    \switchtobodyfont[18pt]
    \endgroup}

\definebodyfontenvironment[18pt]

\testfeatureonce{1000}
   {\begingroup
    \switchtobodyfont[18pt]
    \endgroup}

\stoptext

Wolfgang