Re: Intraword spacing proof of concept

[Hans Hagen <pragma@wxs.nl>]

Charles P. Schaum wrote:
> Hi all,
> 
> Quite a while ago I mentioned letter spacing, or the normal absence
> thereof, in TeX and friends. True, you could skin this cat by
> mathematically scaling the text (font size) by steps to fit the box ---
> the code is out there. But that was not the only way, thought I. Some
> programs also call this general idea tracking, that is, inserting
> positive or negative kerns independent of the \spacingfactor.
> 
> Just for grins I nabbed two snippets from, respectively, manmac.tex and
> texbook.tex. I then added a bit of my own hackery that was inspired by
> DEK's length macro. I realized that a non-counting version of the length
> macro was a memory-friendly way to insert a symbol between any two
> others in a given sequence. What I wanted to insert was a negative kern.
> 
> The negative kern must be small, less than \negthinspace, or else you
> start getting weird effects like a practically chiastic ordering of
> letters, and certainly a chaotic one. The smallest that one dare go
> seems to be -.066667em, the point where the serifs can start running
> together. Using -.033333em really does not show any letters running
> together, yet it still saves space. I got those figures as suggested by
> Knuth's own selections for tightness in the interword spacing.
> 
> And yes, you could theoretically space out the letters, like the soul
> package that does proper Sperrdruck. One major drawback with my kludge
> is the need to use control spaces, else all spaces evaporate. If soul
> were ported to ConTeXt, and it seems like the code might allow that,
> then a version that "spaces in" and "spaces out" could well be possible.

in my opinion letterspacing only makes sense in titles, not in the main 
body of text (i consider kerning to be part of the font design)

anyhow, since we have to letterspace titles and such, there is provision 
for it in the core (non advertised low level stuff)

\stretched {The badness of this line is very bad.}

\hbox spread 2cm{\stretched {The badness of this line is very bad.}}

\def\stretchedspaceamount{.25em}
\stretchednormalcase {The badness of this line is very bad.}

\def\stretchedspaceamount{.5em}
\stretchednormalcase {The badness of this line is very bad.}


\def\stretchedspaceamount{-.125em}
\def\stretchedspacefactor{-4}
\stretchednormalcase {The badness of this line is very bad.}

\hbox{The badness of this line is very bad.}

ps. the negative kerning was not supported, but i enabled it in the beta

ps. in mkiv there is another model, one that permits kerning of 
arbitrary text

Hans

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                                           Hans Hagen | PRAGMA ADE
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