[XeTeX] Font corruption (?) problem

[Ross Moore]

Hi Karljurgen,

On 09/11/2010, at 7:29 AM, Karljurgen Feuerherm wrote:

> Hi again,
> 
> With respect to the problem you mentioned to me... I was speaking with the colleague who put me on to Linux Libertine in the first place; he thinks it may have to do with the fact that the ligatures are stored in the PUA, and that consequently if another font is applied one might get the characters reinterpreted with whatever other glyphs are in there.

No; that is a possible problem with using the .oft font.
It is not the same kind of problem that is encountered using the  libertine.sty 
package. This breaks up the font into Type1 chunks, having at most 256 characters.
These are all down in the range 0--255, as that is all that Type1 supports.
The reason for doing this is that TeX traditionally (before XeTeX and LuaTeX) 
can only support characters up to 255 in .dvi output.

Mapping such a low-range character back to its Unicode point is then done 
via either the CMAP mechanism (which requires a translation table to be supplied 
--- but libertine.sty does not supply this) or by the naming of the glyphs and 
the use of font-encoding vectors.

The problem is manifest when doing a Copy/Paste (and maybe also if searching).
It is dependent upon which PDF browser is used.
For example, copy/paste from Apple's Preview works fine, but it doesn't
work with Adobe Reader or Acrobat Pro. 


> I don't know whether that is likely to be the case or not, but it's a thought for you to pursue if you wish.

Thanks for the thought, but it is not the reason for the specific
issue that is happening here.

> 
> best
> 
> K


All the best,

	Ross

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Ross Moore                                       ross.moore at mq.edu.au 
Mathematics Department                           office: E7A-419      
Macquarie University                             tel: +61 (0)2 9850 8955
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