[Freetype] Legacy software and bitmap-only snfts [was: FreeType bug report]

[Juliusz Chroboczek]

PS> You should also decide on an extenson name other than .ttf, 

I'm thinking of using .otf.  The OpenType spec explicitly allows
bitmap-only OTF fonts.

It should also be legal to generate .ttf fonts, under the condition
that I generate at least one entry in each of hmtx, glyf, and loca
(which I'm doing by default right now).

PS> to avoid that those bitmap only ttf files get confused wwith real
PS> scalable fonts by people out there, otherwise there would be a lot
PS> of bad consequences.

By default, I'm generating fonts which are perfectly valid TTF fonts.
To a non-sbit aware rasteriser, they will appear as fonts with only
one blank scalalble glyph.

The good thing is that no existing software should crash on them.  The
bad thing is that existing software will happily use them, which may
lead to user confusion.

The alternative is to generate no loca or glyf tables at all, and
using the ``OTTO'' signature in the font's header.  Existing software
should refuse to load such fonts, which will minimise user confusion.

I'm waiting for the FreeType crowd to decide whether they wish to
support such fonts.

                                        Juliusz