Scott Horne wrote on 1999-07-02 19:19 UTC:
> TeX fonts also encode several sizes of grouping characters (such as
> parentheses), radical signs, and other characters, and components
> from which to construct arbitrarily large ones.
I consider the TeX set of building blocks for variable-size parenthesis
to be a somewhat ugly hack that I would prefer not to see going into
Unicode. The proper solution to handle variable size parenthesis, roots,
etc. is in my opinion to include into the style sheet files (DSSSL or
whatever we will end up using) representations of tiny algorithms that
convert a size requirement into a set of say B-spline strokes that are
then rendered. This leaves you *much* more freedom in getting the
resizeable object rendered with highest quality over a very wide range
of sizes and styles. The TeX community is already well familiar with
such technology, because Metafont represents every Computer Modern glyph
as a small highly parameterizable drawing algorithm and not as a fixed
glyph. Knuth was just restricted by the simple photo typesetters that he
had available when he developed TeX in the late 1970s. These could not
draw arbitrary freeform lines as they became much later available with
PostScript, therefore the TeX DVI format does not support any graphics
primitives except glyph placement and black rectangles, and consequently
scalable mathematical delimiters had to be constructed from building
block glyphs and not from graphics primitives.
Unfortunately, current style-sheet languages such as DSSSL do not yet
contain suitable graphics primitives either. Fixing this would not only
give you highest quality growing math delimiters, but also much more
flexibility in table and diagram formatting. I think graphic primitives
- such as PostScript offers them - are the way to go for markup and
style sheet languages, and not more 1970s block graphics.
Note how difficult it is to replace in TeX the Computer Modern fonts
with anything else, because of the rich and highly specialized
typographic rendering functionality that is associated with it's math
block graphics symbols. If the variable brackets and roots were instead
drawn by font-independent LaTeX macros using graphics primitives, it
would be much easier to use more common off-the-shelf fonts under TeX
without loosing the math capabilities.
Markus
-- Markus G. Kuhn, Computer Laboratory, University of Cambridge, UK Email: mkuhn at acm.org, WWW: <http://www.cl.cam.ac.uk/~mgk25/>
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