I've been having the same issue (exporting to HTML and PDF, and need all my
graphics filenames to adjust automatically).

I mostly don't use #+CALL though; I just have src blocks.

#+BEGIN_SRC python :session UDpython :exports results :results file
  do_hbar('/tmp/machines-by-os.pdf', (8,1.5), data)
#+END_SRC

Is there any way of interpolating the elisp value into the middle of a src
block?  I guess I can add another #+HEADER line:

#+HEADER: :var filename=(ext "/tmp/machines-by-os")
#+BEGIN_SRC python :session UDpython :exports results :results file
  do_hbar(filename, (8,1.5), data)
#+END_SRC

Is that the recommended method?

Org-mode macros that got expanded in the middle of babel source block text
would be cool. Just saying.



On Tue, Apr 30, 2013 at 10:40 AM, Greg Minshall <minshall@umich.edu> wrote:

> Eric,
>
> just for completeness, and in case this may be of use to other people,
> below is the result of my question + your suggestions.  the following
> illustrates org-mode plus asymptote producing a .svg file during html
> export, and a pdf file during any other (presumably, latex) export.
>
> thanks again, Greg
> ----
> # trying to get graphics that works for both latex/beamer and for html
>
> # here's a suggestion from Eric Schulte
> # http://article.gmane.org/gmane.emacs.orgmode/71301
> # with this clarification
> # http://article.gmane.org/gmane.emacs.orgmode/71393
> # which produced the following
>
> # we define an emacs lisp macro ext that produces a file extension
> # of "svg" or "pdf" depending on whether we are exporting to html or
> # to some other source.  this macro is called when computing the
> # output file name argument in a call to an asymptote routine as in:
> #
> # #+call: rectangle[:file (ext twod-1)](TSIZE=1.0) :results file
> #
> # which calls an asymptote routine (defined in our file) called
> # rectangle to produce a file called twod-1.svg or twod-1.pdf.
>
> # define the ext emacs lisp macro (i think in the following you *need*
> # ":exports results" -- instead of ":exports none" -- to make sure the
> # code is executed during export; the ":results silent" keeps any
> # output -- or nil -- from showing up in the output file.)
>
> #+begin_src emacs-lisp :exports results :results silent
>     (defmacro ext (base)
>       (format "%s.%s" base
>               (if (and (boundp 'backend) (equal backend 'html)) "svg"
> "pdf")))
> #+end_src
>
>
> # follows an example use of the above macro
>
> # first, define a asymptote function (org-named "rectangle") that
> # draws a rectangle
> #+name: rectangle
> #+begin_src asymptote :var TSIZE=1.0 :exports none
>   import trembling;
>   size(100);
>   int off = 2, width = 100, height = 30;
>   string tsize = format("%g", TSIZE);
>   tremble tr0=tremble(angle=0);   // no trembling
>   tremble tr10=tremble(angle=10,frequency=0.1,random=50,fuzz=1);
>
>   picture rectangle(pair sw, pair ne, int offset, string text, tremble tr)
> {
>     picture pic;
>     path g =
>
> (sw.x+offset,sw.y+offset)--(ne.x-offset,sw.y+offset)--(ne.x-offset,ne.y-offset)--(sw.x+offset,ne.y-offset)--cycle;
>     label(pic, text, ((sw.x+ne.x)/2, (sw.y+ne.y)/2));
>     draw(pic, tr.deform(g));
>     return pic;
>   }
>
>   add(rectangle((0,0),(width,height),0, "", tr0));
>   add(rectangle((0,0),(width,height),off, tsize, tr10));
> #+end_src
>
> # now, invoke the above asymptote function, producing a file called
> # either twod-1.svg or twod-1.pdf:
>
> #+call: rectangle[:file (ext twod-1)](TSIZE=1.0) :results file
>
> # now, you can C-c C-e l o or C-c C-e h o and see the image in the
> # two formats
>
> # $Id: parameterizing.org,v 1.2 2013/04/30 14:37:29 minshall Exp $
>
>


-- 
Gary