R devel - Mar 2004 - Changing ComputerModern in postscript(...): A first attempt at contributing....

Hi
First off, thanks to all the various R developers, your package is very
impressive.

I'm not sure what the protocols are for contributing, and I've not done
this
before, so please excuse nay obvious errors or oversights...  Also I'm by no
means an R,TeX/LaTeX, or typesetting expert, I have largely stumbled my way
to this point.

Objective: I'd like to get R postscript(...) to generate output that has the
TeX italic font when I use italic(...) in an R graphic.  

I found out that the R postscript(..font="ComputerModern") outputs
slanted
text when the R function italic(..) is used in a graphic.  I think the text
should use the italic font.
For a quick overview of italic vs. slant vs. oblique see
http://www.eyewire.com/magazine/columns/robin/italic/

A response from Brian Ripley pointed me to the src/main/devPS.c file, and I
traced this behaviour to the use of the slanted/oblique afm font files,
rather than the italic afm font files.  Anyway, I did some homework and
realised that making the change may not be too difficult, except for needing
the Computer Modern afm font files - not included in MikTeX (on my machine
at least).  Fortunately the Latin Modern fonts do include the afm files and
are supposed to be an improvement over Computer Modern, so I thought to make
both changes; update/replace Computer Modern with Latin Modern, and change
the font used when italic text is output.

I read on one OpenSource project that they prefer patches generated from
"diff -u4".  I couldn't see explicit instructions on the R web
site so I've
attached a "diff -u4" file.

Adopting this patch would require adding the following Latin Modern afm font
files to the R afm fonts folder:
lmr10.afm
lmbx10.afm
lmri10.afm
lmbxi10.afm

These fonts are available in the Latin Modern Fonts package.  To find out
about Latin Modern see
http://www.tex.ac.uk/cgi-bin/texfaq2html?label=uselmfonts
Note, I had to leave the CM_symbol_10 file since I'm not sure that there is
a Latin Modern replacement?

Unfortunately I wasn't able to build R using Cygwin (configure works OK but
make fails), so I have not been able to test the changes.  I'll keep looking
into getting R to build, but in the mean time I thought someone may be
interested in the changes?
I think the change I made means that font="ComputerModern" still works
but
outputs Latin Modern fonts and this is misleading, so perhaps drop
"ComputerModern" in favour of "LatinModern" and/or obtain
Computer Modern
italic afm font files and update CM_italic_10.afm and
CM_boldx_italic_10.afm.  I'm not a font pro but it seems that converting
between different font files is not so straight forward, but the Computer
Modern italic afm files may be available to someone?
 
HTH
Mark



Mark Van De Vyver
B.Bus(Hons), PhD(Dist)
Lecturer
Finance Discipline
School of Business
Faculty of Economics and Business
Economics & Business Building H69
The University of Sydney  
Sydney  NSW  2006  Australia
Telephone: +61 2 9351-6452
Fax: +61 2 9351-6461
Mobile: 0428 281407

mailto:mvdv@spamcop.net
http:\\www.econ.usyd.edu.au

We don't in general add things like this, and you can just use the 
family= mechanism to set things up as you like.  We added Computer Modern 
as several people wanted fonts to match the standard TeX fonts.  We don't 
want to change that.  (I believe we did so before we had a general 
mechanism to use a user-specified family.)  

Note that the `italic' font is principally intended to set whole titles in
italic (via font=) and most people prefer oblique for that -- R's standard
graphics font, Helevetica, uses oblique not italic.

To reiterate: all you need to do is prepare suitable .afm fonts and 
specify family= as a five-path character string.

Professor Ripley


On Tue, 16 Mar 2004, Mark Van De Vyver wrote:
> Hi
> First off, thanks to all the various R developers, your package is very
> impressive.
> 
> I'm not sure what the protocols are for contributing, and I've not
done this
> before, so please excuse nay obvious errors or oversights...  Also I'm
by no
> means an R,TeX/LaTeX, or typesetting expert, I have largely stumbled my way
> to this point.
> 
> Objective: I'd like to get R postscript(...) to generate output that
has the
> TeX italic font when I use italic(...) in an R graphic.  
All you need to do is to set the family= argument.
> I found out that the R postscript(..font="ComputerModern")
outputs slanted
> text when the R function italic(..) is used in a graphic.  I think the text
> should use the italic font.
> For a quick overview of italic vs. slant vs. oblique see
> http://www.eyewire.com/magazine/columns/robin/italic/
> 
> A response from Brian Ripley pointed me to the src/main/devPS.c file, and I
> traced this behaviour to the use of the slanted/oblique afm font files,
> rather than the italic afm font files.  
That's what *I* said, so your tracing should have amounted to reading my 
email!  It's not quite correct either: R uses the afm file to know what 
font name to insert in the postscript file.
> Anyway, I did some homework and realised that making the change may not
> be too difficult, except for needing the Computer Modern afm font files
> - not included in MikTeX (on my machine at least).
They are on CTAN.
> Fortunately the Latin Modern fonts do include the afm files and
> are supposed to be an improvement over Computer Modern, so I thought to
make
> both changes; update/replace Computer Modern with Latin Modern, and change
> the font used when italic text is output.
> 
> I read on one OpenSource project that they prefer patches generated from
> "diff -u4".  I couldn't see explicit instructions on the R
web site so I've
> attached a "diff -u4" file.
> 
> Adopting this patch would require adding the following Latin Modern afm
font
> files to the R afm fonts folder:
> lmr10.afm
> lmbx10.afm
> lmri10.afm
> lmbxi10.afm
> 
> These fonts are available in the Latin Modern Fonts package.  To find out
> about Latin Modern see
> http://www.tex.ac.uk/cgi-bin/texfaq2html?label=uselmfonts
> Note, I had to leave the CM_symbol_10 file since I'm not sure that
there is
> a Latin Modern replacement?
It would also require re-encoding them as they are not in a standard 
encoding.  That's why the CM*.afm files there have different names.
(The symbol font is in a completely different encoding.)
> Unfortunately I wasn't able to build R using Cygwin (configure works OK
but
> make fails), 
R cannot be built under Cygwin -- please do RTFM.
> so I have not been able to test the changes.  I'll keep looking
> into getting R to build, but in the mean time I thought someone may be
> interested in the changes?
Which you haven't tested, I gather?
> I think the change I made means that font="ComputerModern" still
works but
> outputs Latin Modern fonts and this is misleading, so perhaps drop
> "ComputerModern" in favour of "LatinModern" and/or
obtain Computer Modern
> italic afm font files and update CM_italic_10.afm and
> CM_boldx_italic_10.afm.  I'm not a font pro but it seems that
converting
> between different font files is not so straight forward, but the Computer
> Modern italic afm files may be available to someone?
They are available to everyone.

-- 
Brian D. Ripley,                  ripley@stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595