This is the README file for the nxyplot package.  nxyplot is a plotting
program for NeXT machines running operating system 2.0 (or higher).

Version 1.5 of nxyplot.
Quick summary of enhancements:
1. More robust handling of input files; they can now have limited text
comments and arbitrary non-ASCII characters.
2. Capability to read and write "format" files.  A format file
contains information about the min/max, line types, etc., and can be
used as a template to allow easily regenerating plots where many
non-default options have been selected.
3. Capability to write an Encapsulated PostScript file describing the
plot.  This file can be included in other applications.
4. Service providing.  Under NeXT system 2.0 and higher, applications
can register as service providers.  This program offers a plotting
service to any application which can put appropriate data on an ASCII
pasteboard.  See the help file (under "Preferences") for more
information.
5. Capability to read compressed files.  This is to help conserve disk
space.

Version 1.0 of nxyplot.
Quick summary of enhancements: can now plot data from multiple files;
can select different fonts for the various labels; better labeling
along the axes.

Summary:
nxyplot is a program for plotting two-dimensional curves, with data
coming from one or more files.  Each file can contain multiple
y-values for each x value.  Each data file should be an ASCII or
compressed file, with each line containing the x-value followed by the
y-values for each curve.  Thus, each data file should look like
x1 y1 ... yn
x2 y2 ... yn
etc., where there are n curves to be plotted.  A sample file
(test2.xyp) is provided to illustrate this format and to use for
testing the program.  The input file can contain text comments provided
that the text contains no periods or numerals, and provided that no
text appears on the first line of the file.

We have tried to comply with the standard NeXT user interface.  The
various panels (controls, lines, symbols, legends) have some
information displayed on them.  They allow manipulation of the line
style, symbol type, legend, minimum and maximum value along each axis,
and titles.  Also provided is the ability to move the legend and to
"zoom" in on a section of the plot.  Printing capability is provided
by standard NeXT system methods; the plot will be automatically scaled
to an 8.5 in. x 11 in. page in either landscape or portrait mode
(depending on whether the screen plot is landscape or portrait).

Writing this program served as our introduction to programming using
the Interface Builder and Objective-C.  We wanted to emulate the
functionality of a program called "xyplot", written by Marshal Merriam
of NASA/Ames Research Center and T. Krysten Nguyen.  The plotting
program "QuickPlot" of Fred Richards (University of Illinois) was very
helpful in showing how to get started with the Interface Builder.

We use this program ourselves and intend to support it (in our spare
time).  Constructive criticism and suggestions for improvement are
welcome; send e-mail to jesperse@rft28.nas.nasa.gov or
pulliam@rft29.nas.nasa.gov.  We always have a wish list.

This code is provided as-is, and no warranty express or implied is
made.  It is definitely not a product of the U.S. Government.  The
source code is not to be used in any commercial for-profit endeavor.

Dennis Jespersen                  Tom Pulliam
jesperse@rft28.nas.nasa.gov       pulliam@rft29.nas.nasa.gov
