[tex-live] pdfTeX and ToUnicode CMaps

[Heiko Oberdiek]

Hello,

I think a better place for this issue is the (ntg-)pdftex mailing list,
therefore I have CCed the ntg-pdftex mailing list.

On Wed, Oct 24, 2007 at 09:25:19AM +0200, Werner LEMBERG wrote:

> > > What exactly is the status of automatic ToUnicode CMap generation
> > > within pdfTeX?  There is a very nebulous entry in the NEWS file
> > > (BTW, the versions in TeXLive's Build and Master tree differ), but
> > > the manual is completely silent about it...
> > 
> > Thanh knows all about it. :-)
> > Did you read patch 580 (http://preview.tinyurl.com/38fjr9)?
> 
> I now did.  Thanks to the pointer.  How comes that this feature is
> neither mentioned in the NEWS file nor in the documentation?  

It was presented by Han at EuroBachoTeX 2007:
  `Font-specific issues in pdfTeX'
(I don't know whether slides exist on-line, via google I only
found a non-existing pdf file, but at least google's html view
was available.)

Section "5. Support for ToUnicode map".

> I consider this as *very bad*.  Lack of documentation is inexcusable.

I think there are unsolved issues. Now there are two methods
for adding CMaps:
(a) \pdffontattr, package cmap
(b) \pdfgentounicode, glyphtounicode.tex

Both methods have its limitations, e.g. (b) only works for Type 1 fonts.
Thus you could need both methods to cover all fonts, but the methods
doesn't know each other, thus fonts can end up with two CMap tables.

Yours sincerely
  Heiko <oberdiek at uni-freiburg.de>