0. Usage
============

diff-pdf is a tool for visually comparing two PDFs.

It takes two PDF files as arguments. By default, its only output is its return
code, which is 0 if there are no differences and 1 if the two PDFs differ. If
given the --pdf option, it produces a PDF file with visually highlighted
differences:

   $ diff-pdf --pdf=diff.pdf a.pdf b.pdf

Another option is to compare the two files visually in a simple GUI, using
the --view argument:

   $ diff-pdf --view a.pdf b.pdf

This opens a window that lets you view the files' pages and zoom in on details.
It is also possible to shift the two pages relatively to each other using
Ctrl-arrows. This is useful for identifying translation-only differences.

See the output of `diff-pdf --help` for complete list of options.



  1. Compiling from sources
=============================

The build system uses Automake and so a Unix or Unix-like environment (Cygwin
or MSYS) is required. Compilation is done in the usual way:

   $ ./configure
   $ make
   $ make install

As for dependencies, diff-pdf requires the following libraries:

 * wxWidgets >= 2.8
 * Cairo >= 1.4
 * Poppler >= 0.10

Note that many more libraries are required on Windows, where none of the
libraries Cairo and Poppler use are normally available. At the time of writing,
transitive cover of the above dependencies included fontconfig, freetype, glib,
libpng, pixman, gettext, libiconv, libjpeg and zlib.