[XeTeX] Fwd: Text figures (Old style figure) in XeTeX

Michael B. Trausch mike at trausch.us
Wed Dec 19 21:36:38 CET 2007

On Wed, 2007-12-19 at 19:28 +0000, Jonathan Kew wrote:
> I think this is happening because Adobe encodes these glyphs in the  
> Private Use Area of Unicode, rather than leaving them unencoded and  
> relying solely on OpenType features to access them. Because of this,  
> the ToUnicode mapping that xdvipdfmx embeds in the PDF will map
> these  
> to PUA codepoints (U+F643..F64C, in the case of the OldStyle  
> numerals) rather than the proper digit codepoints.
> IMO, this is a poor design choice by the font developer; they should  
> not be using PUA character codes for things that are not distinct  
> characters but glyph variants of existing standard characters. To  
> some extent, it may be a legacy of the pre-OpenType days when every  
> glyph had to be directly encoded in some way, in order to be  
> accessible (hence "expert sets", etc.). In these days of Unicode and  
> OpenType, this is no longer necessary or appropriate.
> It may be possible to modify xdvipdfmx's algorithms for ToUnicode  
> generation to handle such fonts better; I'll look into it when time  
> permits.

I have (recently; as in yesterday) just noticed this behavior for these
fonts when typeset with small caps, as well; I am using XeTeX from
TeXLive, and viewing the resulting PDF in Evince.

	--- Mike

Michael B. Trausch                                   mike at trausch.us
home: 404-592-5746, 1                                 www.trausch.us
cell: 678-522-7934                       im: mike at trausch.us, jabber
Ubuntu Unofficial Backports Project:    http://backports.trausch.us/
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