TODO

 * A few constants aren't available with older versions of Freetype.  They
   should do something better than simply not exist, probably croaking if
   they are used.

 * Some characters don't have an outline or bitmap, but can be put together
   from other glyphs.  E.g., magick.pl doesn't work with kochi-minco.ttf
   because it doesn't have a glyph for Acircumflex, but fontforge says it
   does provide that character, just that it doesn't have an outline or
   bitmap.  It says it's composed of U+0041 and U+0302.
   The current situation is that bitmap() will return a 0x0 bitmap, which
   breaks bitmap_magick(), and the outline doesn't cause any problems
   apart from not being there.

 * Tests:
    * decomposing outlines.  Also test the postscript() and svg_path() methods.
    * bitmap_magick() -- skip tests if Image::Magick not installed

 * Maybe provide some defaults for $face->set_char_size(), so that you don't
   have to pass in all four values.

 * $face->glyph_from_char() should work with Unicode characters properly.

 * There should be a way of getting glyphs by index.

 * The underline methods ($face->underline_position() and
   $face->underline_thickness()) should scale their values to the same
   scale as the font.

 * Provide an interface for doing transformations.  This also implies
   supporting the 'advance' vector in glyph slots.  It could be accessed
   with an 'advance()' method, returning just the prevalent component in
   scalar context.  Means 'horizontal_advance()' would be rarely needed.

 * Make $face->kerning() accept glyph objects as well as indices,
   and maybe also allow strings.  In the documentation highlight the
   fact that it accepts glyph indices, not Unicode codepoints, and
   explain why.

 * Handle vertical layout, by accepting a flag to $library->face().
   Various places will have to support this:
    * $face->kerning() should return the y kerning when called in scalar
      context and when in vertical layout.
    * Make sure the metrics information returned is sensible.
    * Make it easy somehow to position characters centered around
      the (vertical) baseline.  (FreeType might do this automatically.)

 * What about top-side bearing, does it mean anything in horizontal layout?
   If so, bind it.

 * Perhaps an interface for selecting charmaps.

 * Check that the things passed to $glyph->outline_decompose() are actually
   code refs.

 * Provide a simple way to generate characters in a Type3 font (or whatever)
   to output Postscript less stupidly.

 * Provide convenience method for generating PDF fragments from outline.

 * Binding of FT_HAS_MULTIPLE_MASTERS, if I can work out what it's for.

 * Some support for doing ligatures would be nice.

 * Maybe the library version would be better as a v1.2.3 type value?
   Might make comparison easier.

 * Attaching files: some support in the $face->attach_file() method,
   but it's completely untested.

 * Need to test scalable fonts that also provide bitmaps.  If we're to
   use the bitmaps then $glyph->bitmap() will have to be more clever
   about deciding when to render.  kochi-mincho provides many fixed sizes.

 * Make $glyph->postscript() (and any similar methods I add) work with
   bitmap glyphs, by getting the bitmap and outputting appropriate PS code
   to draw it.

 * If FT_LOAD_NO_SCALE is used, perhaps $glyph->outline_decompose() should
   return integers, rather than trying to treat the values wrongly as 26.6.

 * Provide some way of iterating over glyphs rather than characters.
   For example, listing 'cursor.bdf' finds no characters, because they all
   have "ENCODING -1 0".

 * Provide a README, if I can think of anything useful to put in it.

 * Figure out how to make the outline available even after the bitmap was
   first loaded, without the kludge of always loading the outline (which
   is probably inefficient).  See the comments in qefft2_glyph_bitmap().