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Two questions

3 messages · Peter Dunn, Barry Rowlingson, (Ted Harding)

Peter Dunn
# 
Hi all

Two questions:

1. I note that help for the postscript device claims "The 
postscript produced by R is EPS (Encapsulated PostScript)
compatible...".  It does not say it is EPS *compliant*.  
Indeed, the EPS produced by R includes a \showpage command 
which I believe (not that I'm an expert!) non-standard EPS.  
My question:  Is there any reason why it is EPS compatible,
but not compliant?  (I ask because the \showpage caused me
a minor trouble once.)

2.  R and S-Plus restrict the available combinations of
link functions and response distributions when using  glm.
The combinations allowed are certainly sensible, but what is
the logic for disallowing other combinations (eg  identity 
link only is allowed for the  gaussian  family)?  I also
know there are ways around it; I was just wondering about
the reasoning.

Thanks,

P.
Barry Rowlingson
#
Peter Dunn wrote:

            

      
      
      
    

        
Adobe's tech documents are here:

http://partners.adobe.com/asn/developer/technotes/postscript.html

  and says

"The showpage operator is permitted in EPS files because it is present 
in so many PostScript language files. Therefore, it is reasonable for an 
EPS file to use the showpage operator, although it is not necessary if 
the EPS file will only be imported into another document. The 
application importing the EPS file is responsible for redefining showpage."

  So it seems that any problem you had with showpage was possibly the 
importing application's fault.

  I've just realised I've been hacking PS files for 15 years now...

Barry Rowlingson
Maths and Stats
Lancaster University
Lancaster, UK

  
  


  


      

    

    

      
      

        


  

        

      (Ted Harding)
    

    

      
      #
    

  


  

      
... and one answer ...

        
On 02-Apr-03 Peter Dunn wrote:

            

      
      
      
    

        
Nothing whatever wrong with this, and it is perfectly standard
and "compliant" and indeed is covered in the PostScript Language
Reference Manual.

Using 'showpage' allows the file to be displayed directly on
any PS device, while the file can be embedded in another document
PROVIDED the embedding PS code redefines 'showpage' to be null
(i.e. /showpage {} def) for the duration of the wrapper.

Some document-generating software, however, can be sloppy about
this, in which case you will indeed have trouble. But that is
the fault of the software, not of the fact that 'showpage' is
present in the file.

Ted.


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E-Mail: (Ted Harding) <Ted.Harding at nessie.mcc.ac.uk>
Fax-to-email: +44 (0)870 167 1972
Date: 03-Apr-03                                       Time: 14:03:33
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