[R] R versions and PostScript files

[peter dalgaard]

This is due to the introduction of sRGB. Since this actually does something (Google for sRGB and you will be approximately as wise as me...), I don't think it is likely to be taken out. You can, however, always edit .ps.prolog. (I would expect that the line

/setrgb { setrgbcolor } def

instead of what is already there would reinstate the old behavior, but no guarantees.
)


On Jul 21, 2011, at 17:26 , (Ted Harding) wrote:

> On 21-Jul-11 13:24:32, Duncan Murdoch wrote:
>> On 11-07-21 3:23 AM, pilchat wrote:
>>> Dear R users,
>>> 
>>> I have a desktop computer and a laptop, both of them
>>> with Ubuntu Lucid. The former has R2.10 installed from
>>> Ubuntu repositories (this is the most recent version
>>> in the repositories), while the latter has R2.13 from
>>> the CRAN repositories.
>>> 
>>> I noticed that postscript files generated with R2.10
>>> are "better" than files generated with the latest release
>>> of R, in particular for plots with colored areas, such
>>> as the output of image or persp. The thing is that my ps
>>> viewer (e.g. gv or evince) is very slow in opening ps
>>> files from R2.13, while it smoothly displays ps files
>>> from R2.10, regardless of "encapsulation".
>>> 
>>> I think this is related to differences in the way the
>>> ps file is generated by the two versions of R, but I
>>> don't know how to go deeper in the matter.
>> 
>> Postscript files are mostly text, so you can compare the
>> two files and > see what the differences are. The NEWS
>> file shows a number of changes since 2.10.0, but I can't
>> see any that would cause problems for viewers.
>> 
>> Duncan Murdoch
>> 
>>> Is there anyone experiencing the same issue? Is there
>>> any solution?
>>> 
>>> Thank you in advance
>>> 
>>> Cheers
>>> Gaetano
> 
> Gaetano has now sent me two files, generated (as he posted
> just now on R-help) by the same commands:
> 
>  setEPS()
>  postscript (file="volc.eps",width=5,height=4)
>  image(volcano)
>  dev.off()
> 
> on his two machines:
> 
> volc2.10.eps generated using R-2.10 on his desktop
>  (the EPS file with fast rendering)
> 
> volc2.13.eps generated using R-2.13 on his laptop
>  (the EPS file with slow rendering)
> 
> I have viewed both files on the same machine, and the
> result indeed is that while volc2.10.eps renders very
> quickly, volc2.13.eps does render very slowly (painting
> in by vertical strips which move jerkily from left
> to right). I estimate that 'gv volc2.10.eps' does the
> rendering in less than 1 second, while 'gv volc2.13.eps'
> takes about 18 seconds.
> 
> Comparing the two files, I think I have found the reason.
> 
> A 'diff' on the two files shows a basic difference in
> definitions of a function used in the plotting:
> 
> [A] In file volc2.10.eps (the fast one):
> 
>  /rgb { setrgbcolor } def
> 
> [B] In file volc2.13.eps (the slow one):
> 
>  /srgb { [ /CIEBasedABC
>            << /DecodeLMN
>                 [ { dup 0.03928 le
>                          {12.92321 div}
>                          {0.055 add 1.055 div 2.4 exp }
>                       ifelse
>                   } bind dup dup
>                 ]
>               /MatrixLMN [0.412457 0.212673 0.019334
>                           0.357576 0.715152 0.119192
>                           0.180437 0.072175 0.950301]
>               /WhitePoint [0.9505 1.0 1.0890]
>>> 
>           ] setcolorspace } def
>  /setrgb { srgb setcolor } def
> 
> 
> Then [A] volc2.10.eps (the fast one) uses commands like:
> 
>  /bg { 1 0 0 rgb } def
> 
> while [B] volc2.13.eps (the slow one) uses commands like:
> 
>  /bg { 1 0 0 setrgb } def
> 
> in each case for exactly the same purpose. Thus [B] the
> slow one uses repeatedly (1157 times) a function setrgb
> which has much higher overheads (see definition above)
> than the function rgb used (1156 times) by [A] the fast one.
> 
> So the difference in performance is *definitely* down to
> a specific difference in how R-2.13 implements 'postscript()'
> compared with R-2.10.
> 
> Hoping this is useful!
> Ted.
> 
> --------------------------------------------------------------------
> E-Mail: (Ted Harding) <ted.harding at wlandres.net>
> Fax-to-email: +44 (0)870 094 0861
> Date: 21-Jul-11                                       Time: 16:26:33
> ------------------------------ XFMail ------------------------------
> 
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.

-- 
Peter Dalgaard
Center for Statistics, Copenhagen Business School
Solbjerg Plads 3, 2000 Frederiksberg, Denmark
Phone: (+45)38153501
Email: pd.mes at cbs.dk  Priv: PDalgd at gmail.com