RE: Canonical equivalence in rendering: mandatory or recommended?

From: Peter Constable (
Date: Thu Oct 16 2003 - 17:13:25 CST

> -----Original Message-----
> From: Peter Kirk []

> I wonder if anyone involved in this is speaking from real experience.
> Peter, I don't think your old company actually tried to implement such
> reordering

No, but my new company has.

> I have heard that your new company
> has tried it and has claimed that for Hebrew the performance hit is
> unacceptable. I am still sceptical of this claim.

Well, you're more than welcome to create an implementation that
demonstrates otherwise and share it with us :-).

> Presumably this was
> done by adding a reordering step to an existing rendering engine. But
> was this reordering properly optimised in binary code, or was it just
> bolted on to an unsuitable architecture using a high level language
> designed for the different purpose of glyph level reordering?

I don't know the details; I suspect it was done within a finite-state

> If, as you agree in principle, this is an issue which goes to the core
> of Unicode, should you not be prepared to take some small performance
> hit in order to conform properly to the architecture?

There's more to life in the real world than conformance to a theoretical
principle, and unfortunately most of us live with constraints as a

> If it is unavoidable to call the same routine (for sorting or any
> purpose) multiple times with the same data, the results can be cached
> that they do not have to be recalculated each time.

That's the kind of thing that would be up to a calling application, not
the rendering engine.

Peter Constable
Globalization Infrastructure and Font Technologies
Microsoft Windows Division

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