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=back

=head1 DEPENDENCIES

Because output is to I<PostScript> most users will want to convert the output 
to some other graphics format. Built-in methods for converting to C<*.png> are
provided. The method of choice, of course, is I<Ghostscript>.


=head2 Ghostscript

The I<Ghostscript> interpreter for I<PostScript> files is free and available
for all platforms. This is what will make sense of your C<*.eps> files and
convert them for viewing on screen. But since it is command-line only (no GUI)
most folks talk to it only through GUI-enabled viewer programs. This module
avoids all that, just talking to I<Ghostscript> for you. Nevertheless, you may
wish to employ a GUI-enabled viewer.

F<http://www.ghostscript.com/>

=head2 Other PostScript Viewers

These too are free. They generally work by interfacing with I<Ghostscript> on
your behalf, saving you the hassle of having to deal with I<Ghostscript>'s
command-line (non-GUI) interface. These are all much more user-friendly.

=over 4

=item FOR WINDOWS ONLY

The program C<GSView.exe> will display C<*.eps> files and also convert them to
to other formats. Conversion from C<*.eps> to C<*.png> is excellent.

=item FOR UNIX ONLY

The program C<gv> will display C<*.eps> files very well. It will not, however
convert them to any other formats.

=item FOR ALL

The Gnu Image Management Program (aka I<The GIMP>) is a full-bodied graphic
image editor which, among its many other features, can also read in C<*.eps>
files via Ghostscript. And any format it can read it, it can also convert and
write out. I<The GIMP> is, of course, both free and open-source.

F<http://www.gimp.org/>

When you open an C<*.eps> file in I<The GIMP> it will pop up a menu for how you
want the C<*.eps> file to be read in. Select the I<Try Bounding Box> checkbox.
Then note the two I<antialiasing> radio buttons. Select I<weak> for text and
I<strong> for graphics. This will make bring up an image which looks just like
the default both which C<gv> and C<GSView> provide.

=back

=head1 INCOMPATIBILITIES

None known as yet.

=head1 BUGS AND LIMITATIONS

Owing to inbuilt addressing limitations of I<PostScript>, data sets may not
exceed 65,535 data points.

This program, being free software, carries absolutely no warranties or
guarantees of any kind, neither expressed, implied, or even vaguely hinted at.

=head1 SCRIPT HISTORY

The I<PostScript> definitions herein embeded derive from a standalone
I<PostScript> program named C<OmniGraph.ps> which I wrote sometime circa 1992.
This I did in response to frustrations over an upgrade by Measurments Group to
the software in their System 5000 strain gage instrument versus the graphing
feature in their older System 4000.

I'd already gotten kind of handy in I<PostScript> from wrangling with the
I<PostScript> prolog files of I<Amiga 2000> programs like I<Excellence!> and
I<Gold Disk> so as to publish in Esperanto for which I could find no fonts.
But that I was able to deal with on my own in due course, and for several
platforms besides my own beloved I<Amiga>.

As an aside I cannot refrain from relating that this particular frustration
also proved to be the font (pun intended) of my initial anger and dismay at
Microsoft. Since once I had learnt how to solve this problem for both the
I<Amiga> and for the I<Macintosh> I next turned, as a community service, to
do so for I<MS Word> and found it imposible. How so? Entirely because
Mr. Gates had done two things to thwart me: First he'd encrypted MS Word's
I<PostScript> prolog file for no good reason. And second, once I had managed
to decrypt said prolog, I next found the fiend to have therein called the
I<PostScript> 'exitserver' command entirely contrary to warnings forbidding
such in the official I<PostScript> docs. My Microsoft-ish experiences since
have only deepened that sentiment further.

As an aside, you may further wish to know that the reason folks now publish 
telephone numbers as 123.555.1212 versus the more traditional 123-555-1212
may also be blamed on Mr. Gates. MSWord sorely frustrated users for lack of 
a non-breaking hyphen (which Amiga, Apple, NEXT and several others all had). 
So to keep telphone numbers from wrapping on a line, poor sods stuck with 
MSWord started using periods. But I digress...

From there I went kind of wild with I<PostScript>, using it in all manner of
ways for which it was probably not intended. This I could in no wise have done
without the continuing example of Don Lancaster, noted I<PostScript> guru, for
his many excellent articles in I<Publish> magazine and elsewhere.

Ref. F<http://www.tinaja.com>

Most of those ancient efforts have now lain fallow many a year. But once again,
this time in frustration over a (for most folks, trifling) lack in the Perl
module C<GD::Graph::lines>, I have resurrected my old, trusty C<OmniGraph.ps>
and grafted it piecemeal, with some changes, into this new module
C<Chart::EPS_graph.pm> so as to work around that specific issue where
C<GD::Graph::lines> chokes on dual Y axes needing multiple channels.

=head1 AUTHOR

Gan Uesli Starling <F<gan@starling.us>>

=head1 LICENSE AND COPYRIGHT