[NTG-context] [MetaFun] Trying to understand outlinetext, 'stretch' effect and \kerncharacters

31 Dec 2021

      Dear list,

I have the following graphic

\startuseMPgraphic{TitleGraphic}
draw outlinetext.b (\MPstring{TitleText})
    (withcolor "titlefg")
    (withcolor "titleoutline");
\stopuseMPgraphic

which I tried to use as follows to produce a stylized 'title' head:

\setupMPtext{TitleText}{%
\starteffect[stretch]\bfc\namedstructurevariable{title}{title}\stopeffect}
\useMPgraphic{TitleGraphic}

[colors "titlefg" and "titleoutline" are set using \definecolor]

But, the 'stretch' effect caused by \starteffect[stretch]…\stopeffect does not 
work with 'outlinetext' method in the MPgraphic. I have verified that the 
desired effect is produced using 'textext' method instead. But in that case I 
have to cheat (i.e draw twice; once with blownup) to get the text outline.

Now, if I write instead 

\setupMPtext{TitleText}{%
\kerncharacters[0.15]\bfc\namedstructurevariable{title}{title}}
\useMPgraphic{TitleGraphic}

then the desired effect is produced. As such, my purpose is served well by 
using \kerncharacters.

Nonetheless, I request your kind help in understanding why this is happening 
and/or if I am doing something wrong.

Thanks,
kauśika