DiffPDF
===========

DiffPDF is used to compare two PDF files.

By default the comparison is of the text on each pair of pages, but
comparing the appearance of pages is also supported (for example, if a
diagram is changed or a paragraph reformatted). It is also possible to
compare particular pages or page ranges. For example, if there are two
versions of a PDF file, one with pages 1-12 and the other with pages
1-13 because of an extra page having been added as page 4, they can be
compared by specifying two page ranges, 1-12 for the first and 1-3, 5-13
for the second. This will make DiffPDF compare pages in the pairs (1,
1), (2, 2), (3, 3), (4, 5), (5, 6), and so on, to (12, 13).

A couple of example PDF files are provided online so that you can try it
out. PDF files can be loaded from the GUI (by pressing the File #1 and
File #2 buttons), or by specifying them on the command line. More
information is available in the program's tooltips and About box.


Compiling and Installing DiffPDF
================================

Prerequisites: A C++ compiler, the Qt 4 libraries (I test with Qt 4.6;
Qt 4.4 and 4.5 also work, but need a compiler with tr1 support), and the
Poppler libraries (including Poppler's Qt 4 headers).

1. Unpack the archive file, diffpdf-XXX.tar.gz
2. Change directory to diffpdf-XXX
3. Run qmake # On some systems, e.g., Fedora or Ubuntu, run qmake-qt4
4. Run make
5. Copy or soft-link the diffpdf executable to somewhere on your PATH

That's it!


Running DiffPDF
===============

A pair of tiny example files are available:
http://www.qtrac.eu/boson1.pdf and http://www.qtrac.eu/boson2.pdf. You
can use these to see the difference between text and appearance
comparisons and to get a feel for how DiffPDF works.

If you hit a bug, please report it to mark@qtrac.eu. Be sure to include
"DiffPDF" in the subject line and specify the version you are using
and details of your system, e.g., operating system name and version,
compiler name and version, Qt library version, Poppler library version.


License
=======

This program was written by Mark Summerfield.
Copyright (c) 2008-10 Qtrac Ltd. All rights reserved.

This program is free software: you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by the
Free Software Foundation, either version 2 of the License, or (at your
option), any later version. This program is distributed in the hope that
it will be useful, but WITHOUT ANY WARRANTY; without even the implied
warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License (in file gpl-2.0.txt) for more details.
