[OS X TeX] copy and paste

Ross Moore ross.moore at mq.edu.au
Sun Jul 25 17:30:30 EDT 2010

Hi Alan,

On 26/07/2010, at 6:57 AM, Alan T Litchfield wrote:

> I too experience that problem. Mostly if I copy content from Word, but any program that has made use of ligatures. The default encoding  is MacOS Roman.
> Ross the problem isn't in typesetting and losing ligatures,

That is not what my comments address.

> it is when pasting text from other sources that have ligatures and these are lost when the text is pasted into TeXShop. I don't recall this being a problem before. I am using 10.5.8.

It has *always* been a problem, related to:

 a.  which code-points the font uses to put its ligature characters,
     and whether there is an encoding vector that provides the
     standard Adobe name for those glyphs;

 b.  what extra features are included when the font is embedded
     within a PDF; e.g. to make up for any deficiencies in (a).

 c.  whether the Copy/Paste software recognises the features
     provided in (a) and/or (b).
     For example, you may get a different result according to
     whether you are copying from windows of Adobe applications
     or from Apple applications (e.g. Preview). 

So you see that there are quite a few variables that come
into play here.

> The default font is Helvetica 10.

That is yet another variable.

However if the ligature has copied, but is not contained within
the target font, then you would expect to see a "missing character"
glyph displayed.  (touchwood)

The lack of this tends to indicate that the ligature did not copy
at all. The presence of a properly constructed CMAP within the PDF
usually fixes this.  
Note that you want the CMAP to map the ligature 'ff' to 'f'+'f'.

Alternatives are to map to the proper Unicode code-point
  (but this requires the target font to support it)
or to a point in the Private Use area --- where only some
specific fonts support it.

Neither of these is entirely satisfactory, 
yet I've seen examples of both.

> Alan

Hope this helps,


Ross Moore                                       ross.moore at mq.edu.au 
Mathematics Department                           office: E7A-419      
Macquarie University                             tel: +61 (0)2 9850 8955
Sydney, Australia  2109                          fax: +61 (0)2 9850 8114

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