From: Richard Cook (rscook@socrates.berkeley.edu)
Date: Thu Oct 14 2004 - 15:36:39 CST
On Oct 13, 2004, at 1:42 PM, Eric Muller wrote:
> Going back to the original scenario, to make my point clearer:
>
> System A, a subset of FileMaker, has {U+0065, U+0303, U+1EBD} as its
> repertoire. When presented with the input <U+0065, U+0303>, it
> produces the output <U+1EBD>.
>
> System B, my rendering system, has {U+0065, U+0303} as its repertoire.
> When presented with the input <U+0065, U+0303>, it produces a correct
> rendering. When presented with the input <U+1EBD> it outputs a smiley.
>
> Both systems are conformant (I would hope), yet putting them together
> does not mean that the result is automatically conformant, even on the
> intersection of their repertoire. Hence, one cannot attribute the
> problem that Richard is seeing to either system. The problem belongs
> to Richard, when he did put the two systems together.
Well, if it belongs to me, I'll happily give it away for free to anyone
willing to take it off my hands.
> If we want some automatic guarantee of conformance for combinations of
> conformant systems, then we need at least to impose that the
> repertoire supported by conformant implementations be closed under
> canonical equivalence. Such a condition is not there today. It has
> interesting consequences: e.g. U+2FA1C is canonically equivalent to
> U+9F3B, so the BMP is not closed under canonical equivalence, so no
> conformant system could make its repertoire exactly the BMP.
If someone wants to normalize my text into precomposed things, that's
all well and good, so long as there's a fallback mechanism for
rendering via a font which may have only the decomposed parts.
I don't know if this is the same as saying that "we need at least to
impose that the repertoire supported by conformant implementations be
closed under canonical equivalence".
But, I say this after spending *way* too much time yesterday adding
precomposed things to my font. You might think that I can rationalize
it, thinking that now the diacritic placement will be somewhat better
than it was before. But I thought the diacritic placement was adequate
to begin with. And I can't predict what new precomposed things I might
need to support in the future.
-Richard
This archive was generated by hypermail 2.1.5 : Thu Oct 14 2004 - 15:38:16 CST