D. Starner wrote:
It's a simple combining character. Even if you can't do arbitrary circlesThis sounds nice, but in practice, things are a bit more complicated. Systems are not enough.
around characters, you can take one character sequence and map it to the
glyph in a font. Systems that can't do even that need to be fixed.
The Unicode architecture is such that combinations are indeed generative, in the sense that simply adding a character "ENCLOSING <your favorite shape>" instantly allows the representation of signs which are made of a suitable base enclosed by the shape in question.
Fonts on the other hand are much less generative. Firstly, it is sometimes appropriate to have multiple graphics for such a character, e.g. of different sizes. Secondly, regardless of the choice between positioning of two glyphs or the creation of a single glyph, there is typically some work to be done that depends either on the number of bases (e.g. identify on attachment point for each base), or even worse, the number of combinations.
But the real obstacle for a generative approach is QA: if as a font vendor you want to ensure some level of quality, then it is hard to avoid human work essentially proportional to the number of base+mark *combinations* you claim to support. If you don't *look* at a combination, at a number of sizes (to take into account rasterizing and hinting effects), in different contexts, then there is a chance that it does not happen as expected.
I have no problem with people taking those chances or deciding their fonts are ok, or whatever. But I have a real problem if somebody else claims that *I* must take those chances, or that *I* must do an amount of work that is not justified by my commercial goals, or that *my* fonts are broken if I decided to not support some combination, or that *my* fonts are ok even if the result is below my standards.
Eric.

