Unicode of Death 2.0

[Richard Wordingham via Unicode]

On Sun, 18 Feb 2018 14:13:22 +0100
Philippe Verdy via Unicode <unicode at unicode.org> wrote:

> But any operation in OpenType that requires reordering requires a
> glyphs buffer. This could even apply to Latin if Microsoft really
> intends to support normalization (i.e. canonical equivalences) in its
> own USE engine (for now it does not) because it would also require a
> glyphs buffer to allow correct reordering of glyphs (according to
> their properties, notably for "beforebase", or for special placement
> of some diacritics such as the cedilla that moves from "belowbase" to
> "abovebase" when the base is the letter "g").

The examples accompanying the OpenType specification assume a font may
insert spacing glyphs for punctuation in French, so there's no need to
consider anything complicated.

Microsoft renderers aren't immune to problems.  I've had whole lines
vanish because of undocumented shortcomings in the
implementation of multiple ligations in a contextual substitution.  (I
presume the vanishing was to save me from something worse, such as
memory corruption.)  I couldn't see anything wrong with the maxp
parameters.  OpenType semantics have not been thoroughly reverse
engineered.

Richard.