.. _install_deps:

Installation of dependencies
============================

The dependencies `Tkinter`_ and `ghostscript`_ can be installed using your system's package manager. You can run one of the following, based on your OS.

.. _Tkinter: https://wiki.python.org/moin/TkInter
.. _ghostscript: https://www.ghostscript.com

OS-specific instructions
------------------------

For Ubuntu
^^^^^^^^^^
::

    $ apt install python-tk ghostscript

Or for Python 3::

    $ apt install python3-tk ghostscript

For macOS
^^^^^^^^^
::

    $ brew install tcl-tk ghostscript

For Windows
^^^^^^^^^^^

For Tkinter, you can download the `ActiveTcl Community Edition`_ from ActiveState. For ghostscript, you can get the installer at the `ghostscript downloads page`_.

.. _ActiveTcl Community Edition: https://www.activestate.com/activetcl/downloads
.. _ghostscript downloads page: https://www.ghostscript.com/download/gsdnld.html
.. _as shown here: https://java.com/en/download/help/path.xml

Checks to see if dependencies were installed correctly
------------------------------------------------------

You can do the following checks to see if the dependencies were installed correctly.

For Tkinter
^^^^^^^^^^^

Launch Python, and then at the prompt, type::

    >>> import Tkinter

Or in Python 3::

    >>> import tkinter

If you have Tkinter, Python will not print an error message, and if not, you will see an ``ImportError``.

For ghostscript
^^^^^^^^^^^^^^^

Run the following to check the ghostscript version.

For Ubuntu/macOS::

    $ gs -version

For Windows::

    C:\> gswin64c.exe -version

Or for Windows 32-bit::

    C:\> gswin32c.exe -version

If you have ghostscript, you should see the ghostscript version and copyright information.

If you choose not to install ghostscript using the Camelot `OS-specific
instructions`_, there is risk of an incomplete installation (for example,
the choosen distribution only installs the ghostscript ``gs`` binary and not
the libraries).

.. _OS-specific instructions: #os-specific-instructions

If the ghostscript application libraries are not installed correctly, the
attempt to use ``read_pdf`` (using the example on the Camelot home page) will
fail as follows (Traceback truncated - full example stack trace available
`here`_)::

    >>> import camelot
    >>> tables = camelot.read_pdf('foo.pdf')
    OSError: dlopen(libgs.so, 6): image not found

.. _here: https://github.com/camelot-dev/camelot/issues/193

A correct installation of ghostscript will result in the example returning a
TableList object::

    >>> import camelot
    >>> tables = camelot.read_pdf('foo.pdf')
    >>> tables
    <TableList n=1>