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

[Hans Hagen]

On 12/31/2021 3:13 AM, kauśika via ntg-context wrote:
> 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}

low level pdf magic ... so not done in mp

> [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}

tex magic so done in tex

> 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.
\starteffect is kind of old (comes from mkii), but you could use the 
pseudo font feature effect in mkiv / lmtx which then makes a real font 
instance instead of mixing in some pdf magic

Hans


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