Re: [NTG-context] Scaling down symbols and emojis

19 Jan 2019


      On Fri, Jan 18, 2019 at 4:44 PM User 19087  wrote:
...
There must be some other method (at least via luatex) to
obtain the 'x' and 'xx' sizes as workable dimensions.
I've come up with the following macro and I'd like some feedback. Will
it work consistently? Any suggestions for improvement?


% A '\start...\stopluacode' block inside a macro is just as bad (or worse?) to
% escape as '\ctxlua' code. So create a function here for use elsewhere.
%
% There were multiple font sizes in the "specification" and "parameters"
% tables, hopefully I picked the right one.
%
% It turns out that for ConTeXt there is a difference between the 10pt and
% 10.0pt sizes: the former is predefined in the body font environment that
% ships with ConTeXt while the latter causes ConTeXt to generate a new body
% font environment. Unfortunately '\the' displays values with trailing 0s, and
% so the result must be converted to a string and truncated in lua.
\startluacode
userdata = userdata or {}
userdata.fontsize = function ()
    local fs
    fs = font.getfont(font.current()).specification.size
    fs = tostring(fs/2^16):gsub("%.?0+$","") .. "pt"
    return fs
end
\stopluacode

% In some situations the 'tx' and 'txx' sizes are ignored by ConTeXt. This
% macro determines the font size that would have been used by such a command
% and switches the entire body font to that size for the duration of the second
% argument. The chosen size depends on the 'x' and 'xx' values of the specific
% body font environment nearest in size to the current body font, though the
% font itself (via definebodyfont) may override those values.
\define[2]\tosize{%
    % Use a scratch box to prevent any typesetting. Otherwise changes to the
    % font size would be compounded: 'tfxx' remaining in effect after
    % 'switchtobodyfont'. I've also tried stop...starthiding, but that prevents
    % all processing of contents.
    \setbox\scratchbox\hbox{%
        #1%
        % Use a global lua variable rather than globally setting a scratch
        % register.
        \startluacode
        userdata = userdata or {}
        userdata.lastfontsize = userdata.fontsize()
        \stopluacode%
    }%
    {\switchtobodyfont[\ctxlua{context(userdata.lastfontsize)}]#2}%
}

Test{\tfx Test}
\tosize{\tfx Unwanted}{Test{\tfx Test}}