[DVIPDFMx] bug in dvipdfmx wrt diacritics?

[Karl Berry]

Forwarding this mail for you, Matthias, since ChoF has already seen it.
(And hopefully for posterity so the bug doesn't get lost.)
The font involved is Charter.  The thread starts at
http://tug.org/pipermail/tex-live/2011-September/030130.html

Best,
karl


Date: Sat, 10 Sep 2011 10:33:51 +0100
From: Jonathan Kew <jfkthame at googlemail.com>
To: reinhard.kotucha at web.de, Jin-Hwan Cho <chofchof at ktug.or.kr>
Cc: Norbert Preining <preining at logic.at>, TeX Live <tex-live at tug.org>
Subject: Re: [tex-live] bug in dvipdfmx wrt diacritics?

On 10 Sep 2011, at 00:41, Reinhard Kotucha wrote:

> The error message
> 
> ** WARNING ** Obsolete four arguments of "endchar" will be used for
> Type 1 "seac" operator.
> 
> doesn't mention only seac but also endchar.  Since seac doesn't use
> endchar itself, I suppose that dvipdfmx has problems with the glyphs
> supposed to be combined, rather than with the seac routine itself.
> 
> In order to find out what the `four arguments of "endchar"' are, you
> have to stop the program when endchar is called and see what's on the
> stack at this time.

I think this must be referring to the feature described in Appendix C
(Compatibility and Deprecated Operators) of the Type 2 Charstring Format
spec, available from
http://download.microsoft.com/download/8/0/1/801a191c-029d-4af3-9642-555f6fe514ee/type2.pdf,
or no doubt somewhere on Adobe's site.

Interestingly, I don't see any mention of this feature in the Adobe Type
1 Font Format spec at
http://partners.adobe.com/public/developer/en/font/T1_SPEC.PDF, which
seems to imply that it is very much obsolete/deprecated.

It seems that in certain circumstances, when (x)dvipdfmx is converting
glyphs from a Type 1 font to Type 2 charstrings, it tries to use this
obsolete feature, and apparently some PDF readers choke on the result.

I'm not sure why (x)dvipdfmx does this, or how easy it would be to
modify the code to avoid this issue; I haven't ever studied or
understood all this font-handling code in detail. Perhaps ChoF could
offer some advice?

JK