It's not especially rare to have on-the-fly adjustment of
word wrapping in a text editor. For instance, Metapad, a
very likable Notepad replacement, adjusts word wrap as
you resize its window. You become very aware of hard returns
vs. flowed text! (I love its "Commit word wrap"
command, btw.)

Many years ago, Scientific American (probably when Knuth's
Metafont was first announced) printed a quite-remarkable
and fairly-long paragraph in which the type style of each
letter changed progressively from, say, serif, to sans-serif.
The change between, say, consecutive e's was imperceptible,
but you could plainly see the progressive change along
the course of the whole paragraph.

The text was created (very likely) by Metafont, probably
in TeX context (sorry for the pun), by giving each character
(or possibly small blocks) different parameters to define
the character's shape. The difference between consecutive
parameters was quite small.

I'm not sure I understand what Metafont is, btw, but if it
makes sense in this message, that's sufficient, for now.

With modern very-fast CPU chips, it should be quite practical
to set up a group of sliders to permit on-the-fly
redefinition of the Metafont parameters that define the
appearance of the displayed face. This redefinition would
quickly or immediately modify all text displayed on the
screen.

Imagine being able to vary such parameters as x-height (in
proportion to cap. height, or, vary cap height, keeping
x-height fixed). Or, vary stroke weight, from the extremes
being ultralight and extra-bold (unless done with a lot of
sophistication, the result could look pretty bad, as does
"algorithmic italics"!)

Other possibilities would be serif "weight", aspect ratio,
looseness/tightness of inter-letter spacing, perhaps
ratio of stroke thickness for horiz. vs. vertical, with
progressive changes for various angles. (A simple cap O
could start as a simple circle with a constant-width stroke,
but could be thus modified to have its thickest portions
vertical; its outline form would then contain an
ellipse or two.

Some modifications could be restricted to certain details,
such as the size of the loop in a small e (and probably
the loop in the small a, the kind that is shaped like a tiny
small "d" with a left-pointing "flag" at the top).

Ascender and descender length are yet more.

Imagine a novel in which the author trims the typography of
the text to enhance the mood; that could easily be over-done.
Maybe it's just simply a bad idea; a well-designed book
with (as usual) just one carefully-chosen face for body text
is very workable.

This is not the first time I've thought that what current
computer technology permits, has outstripped our imagination
about what we can do with it. Nevertheless, one does need to
realize that just because something can be done doesn't say
it should be done.

Best regards,

--
Nicholas Bodley |@| Waltham, Mass.
Opera browser fan/user