It's primarily for the display. There's a small performance hit for the
surrogate processing that we weren't willing to impose on everyone given
that there were no glyphs yet.
From: Markus Scherer [mailto:email@example.com]
Sent: 12 October, 2000 03"15
To: Unicode List
Subject: Re: lag time in Unicode implementations in OS, etc?
so, what is there to be turned on and off in win2k if surrogate pairs
are already handled as single units?
if fonts just don't contain mappings and glyphs for pairs, then the
layout engine will ignore them anyway until fonts provide that data.
> John McConnell wrote:
> Windows 2000 does support surrogates as defined in Unicode 2.0 e.g. it
recognizes them when
> converting to/from UTF-8 & OpenType recognizes new cmap types for
> The remaining steps e.g. fonts that display Ext B and sorting methods
that integrate surrogate
> pairs in culturally correct ways, depend on the final assignments of
the new ranges. That isn't
> in Unicode 2.0 (or 3.0).
> Chris Pratley wrote on 2000-oct-03:
> > Surrogate support was not turned on by default in Win2000 because
> > Windows team was waiting for the standard to be finalized. It was
> > late, so to reduce the potential impact they had it off - a safe bet
> > the standard was still 1+ years from completion.
> which standard? unicode 2.0 introduced surrogates in 1996. iso 10646-1
got amended with utf-16 in 1996, too.
> there was nothing new in the technical issues of how to deal with
utf-16 since then.
> > Chris
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