/**
@page files_root Data source file formats

Depending how @b HippoDraw was configured when built, it supports
creating a data source by reading a file in several formats.  The
file formats supported are

@li @ref file_ascii
@li @ref file_fits (optional)
@li @ref file_root (optional)

The file may be read using either the @ref canvas_menu_file on the
canvas window or by Python using the @ref python_interact.

@section file_ascii ASCII file

The @b HippoDraw application can read and write NTuple data to a plain
text file.  The format is quite simple.  Here is the contents of such
a file.

@verbatim

Mark II Z0 scan
Energy	Sigma	binsize	error
 90.73999786  29  0.25999999  5.9000001 
 91.05999756  30  0.23  3.1500001 
 91.43000031  28.39999962  0.25999999  3 
 91.5  28.79999924  0.28999999  5.80000019 
 92.16000366  21.95000076  0.22  7.9000001 
 92.22000122  22.89999962  0.25  3.0999999 
 92.95999908  13.5  0.20999999  4.5999999 
 89.23999786  4.5  0.28  3.5 
 89.98000336  10.80000019  0.27000001  4.5999999 
 90.34999847  24.20000076  0.25999999  3.5999999 

@endverbatim

The first line is the title.  It can contain any number of spaces and
is terminated by the new line character.  The second line contains the
labels.  You can't see it but they are separated by the tab character
to allow blanks to be in the labels.  The remaining lines are the
data, row by row.  Any white space can separate the data.  The title
line and labels line can be missing. The labels can't be pure numbers,
or it will be read as data.


@section file_fits FITS files

<a href="http://heasarc.gsfc.nasa.gov/docs/heasarc/fits.html">
FITS</a> (Flexible Image Transport System) is the standard
astronomical data format endorsed by both NASA and the IAU. If @b
HippoDraw was configured with CFITSIO, then FITS file containing
images and binary or ASCII tables are supported.  A FITS file can be
read with C++ or Python using the FitsController class.  The example
of @ref examples_fits_file with Python shows how it is done and is
available in the @em examples subdirectory of the installation.


@section file_root ROOT files

Limited support for reading data from a ROOT file is supported if @b
HippoDraw was configured for ROOT support.  The C++ @ref
ntuple_roottuple explains these limitations.  A ROOT file can be read
with C++ or Python using the RootController class.  The example of
@ref examples_root_file with Python shows how it is done and is
available in the @em examples subdirectory of the installation.

*/