[openglean-devel]Font support.

[Richard R. <sf...@ol...>]

I've been fiddling a bit with the gleanfonts genfonts program and
compile.sh which runs genfonts.

One thing that I've more or less decided, for the near term, is
to try to fill out a a fairly useful set of basic fonts at various
uniform sizes, with bold, italic, and bold-italic versions at
each resolution.

There are a few things on my mind:

 * Eventually, I want to redo the font API to work in model
   space for all fonts.  (Bitmapped fonts will then become
   textures.)  At that point, only a few actual font sizes
   would be built into the library (probably about 3 sizes),
   with mipmapping.  Since the bitmapped fonts are presently
   blitted into the graphics area, however, I think that
   a large set of sizes is presently called for.

   This is just a heads-up both about the addition of new
   sizes coming soon and that those sizes will likely
   be replaced by textures.

 * It turns out that using the genfonts program, some
   fonts (e.g., TimesRoman) are available in "italic" form but not
   "oblique", while others (Helvetica) are in an "oblique" form
   but have no italicized version.  The difference between italics
   and obliques is that obliques are just slanted, while italics
   tend to be a little curly.

   I am undecided if I should try to retain the two different
   modes.  Opinions?  I'm inclined, for simplicity's sake,
   to use italicized typefaces where I can, and where no italics
   exist, use obliqued typefaces and just call them "italics".

 * Italics and obliques, by virtue of slanting, bring a new
   aspect into issue.  In most fonts, you have an origin
   of the letter and a distance to advance the origin (cursor)
   after rendering---but the character is permitted to use some
   space to the left of the letter.  Basically, italics and slanting
   can mess up horizontal spacing.


The upshot is that adding new fonts to the library should be
difficult, but making a good API for using the fonts properly
will bring some new issues.

For today, I am content to expand the font set, and I already
planned to overhaul the API anyway.  But I thought that I'd
toss this out for anyone to discuss.

-- 
  "I probably don't know what I'm talking about."  http://www.olib.org/~rkr/