[magick-users] jpg to eps keeping all pixels

[luis at itaapy.com]

> The problem is that, without any further settings, IM assumes a
> resolution of 72 dpi for EPS files. You have to set the resolution via
> the -density option. Assume the resolution of the JPEG file is 150 dpi
> this would be
> convert tesp.jpg -density 150 test.eps

My input are jpeg files with different sizes::

  $ identify test.jpg
  test.jpg JPEG 809x588 DirectClass 89kb
  $ convert -density 72 test.jpg test.eps ; identify test.eps
  test.eps PS 809x588 809x588+0+0 DirectClass 1.4mb

for other jpg::

  $ identify aa.jpg
  aa.jpg JPEG 800x600 DirectClass 72kb 0.080u 0:02
  $ convert -density 28.34 aa.jpg aa.eps; identify aa.eps
  aa.eps PS 800x600 800x600+0+0 DirectClass 1.4mb

How can I pre-calculate the "-density 72" and "density 28.34"
with the data I get from identify ?

Luis