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

DiffPDF is used to compare two PDF files.

By default the comparison is of the words on each pair of pages, but
comparing character by character is also supported (e.g., for
logographic languages). And there's also support for comparing the pages
by appearance (for example, if a diagram is changed or if a paragraph is
reformatted, or a font changed). 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.

(If you want a command line tool for comparing PDFs see
http://www.qtrac.eu/comparepdf.html.)

Home page: http://www.qtrac.eu/diffpdf.html

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

Prerequisites: A C++ compiler, KDE's Extra CMake Modules, the Qt 5 libraries,
and the Poppler libraries. Linux and BSD users should be
able to get everything through their package management system---and
some distros already include diffpdf so you don't even have to build it.
Mac OS X users can get a compiler by installing Xcode; you'll need to
get Qt and Poppler separately.

1. Unpack the archive file, diffpdf-XXX.tar.gz
    $ tar xvfz diffpdf-XXX.tar.gz
2. Change directory to diffpdf-XXX
    $ cd diffpdf-XXX
3. Create a build folder and go there;
    $ mkdir build && cd build
4. Run cmake;
    $ cmake ..
5. Run make
    $ make
6. Optional: install the diffpdf executable;
    $ make install
7. Only the executable is needed (although `make install` will install also other files);
   all the files that were unpacked or generated can be safely deleted.

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 © 2008-13 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.
