pikepdf Documentation
=====================

.. figure:: /images/pike.jpg
   :align: right
   :alt: A northern pike
   :figwidth: 30%

   A northern pike, or *esox lucius*. [#img1]_

**pikepdf** is a Python library allowing creation, manipulation and repair of
PDFs. It provides a Pythonic wrapper around the C++ PDF content transformation
library, `QPDF <https://github.com/qpdf/qpdf>`_.

Python + QPDF = "py" + "qpdf" = "pyqpdf", which looks like a dyslexia test and
is no fun to type. But say "pyqpdf" out loud, and it sounds like "pikepdf".

At a glance
-----------

pikepdf is a library intended developers who want to create, manipulate, parse,
repair, and abuse the PDF format. It supports reading and write PDFs, including
creating from scratch. Thanks to QPDF, it supports linearizing PDFs and access
to encrypted PDFs.

.. code-block:: python

   # Rotate all pages in a file by 180 degrees
   import pikepdf
   my_pdf = pikepdf.Pdf.open('test.pdf')
   for page in my_pdf.pages:
      page.Rotate = 180
   my_pdf.save('test-rotated.pdf')

It is a low level library that requires knowledge of PDF internals and some
familiarity with the PDF specification [#pdfrm]_. If you just want to generate
content as PDF something like reportlab may be more suitable.

pikepdf would help you build apps that do things like:

.. figure:: /images/pike-cartoon.png
   :align: right
   :alt: A cartoon sketch of a pike
   :figwidth: 30%

   Pike fish are tough, hard-fighting, aggressive predators. [#img3]_

* :ref:`Copy pages <copyother>` from one PDF into another
* :ref:`Split <splitpdf>` and :ref:`merge <mergepdf>` PDFs
* Extract content from a PDF such as text or :ref:`images <extract_image>`
* Replace content, such as :ref:`replacing an image <replace_image>` without
  altering the rest of the file
* Repair, reformat or :meth:`linearize <pikepdf.Pdf.save>` PDFs
* Change the size of pages and reposition content
* Optimize PDFs similar to Acrobat's features by downsampling images,
  deduplicating
* Calculate how much to charge for a scanning project based on the materials
  scanned
* Alter a PDF to meet a target specification such as PDF/A or PDF/X
* Create well-formed but invalid PDFs for testing purposes

What it cannot and never will do:

.. figure:: /images/pikemen.jpg
   :align: right
   :alt: A square of pikemen, carrying pikes
   :figwidth: 30%

   pikepdf will not help you defend yourself against a calvary charge. [#img2]_

* Rasterize PDF pages for display (that is, produce an image that shows what
  a PDF page looks like at a particular resolution/zoom level) – use
  Ghostscript instead
* Convert from PDF to other similar paper capture formats like epub, XPS, DjVu,
  Postscript – use MuPDF or PyMuPDF
* Print to paper

Requirements
~~~~~~~~~~~~

pikepdf currently requires **Python 3.5+**. As this is a new library there are
no plans to support Python 2.7 or older versions in the 3.x family, but pull
requests to backport would be considered.

Similar libraries
~~~~~~~~~~~~~~~~~

Unlike similar Python libraries such as PyPDF2 and pdfrw, pikepdf is not pure
Python. Both were designed prior to Python wheels which has made Python
extension libraries much easier to work with. By leveraging the existing mature
code base of QPDF, despite being new, pikepdf is already more capable than both
in many respects – for example, it can read compress object streams, repair
damaged PDFs in many cases, and linearize PDFs. Unlike those libraries, it's not
pure Python: it is impure and proud of it.

It's almost certainly faster than the pure Python libraries at loading and
saving PDFs.

In use
~~~~~~

pikepdf is used by the same author's `OCRmyPDF
<https://github.com/jbarlow83/OCRmyPDF>`_ to inspect input PDFs, graft the
generated OCR layers on to page content, and output PDFs. Its code contains main
practical examples, particular in ``pdfinfo.py``, ``_weave.py``, and
``optimize.py``. pikepdf is also used in the test suite.


.. toctree::
    :maxdepth: 2
    :caption: Introduction
    :name: intro_toc

    installation
    changelog
    tutorial
    objects

.. toctree::
    :maxdepth: 2
    :caption: Reference
    :name: reference_toc

    pikepdf
    arch
    resources

.. rubric:: References

.. [#img1] `Public domain image <https://en.wikipedia.org/wiki/File:Esox_lucius1.jpg>`_.

.. [#img3] `CC0 iamge <https://pixabay.com/en/pike-fish-predator-shchuchin-2612354/>`_.

.. [#img2] `CC-BY-SA 2.0 image <https://commons.wikimedia.org/wiki/File:Pike_square_img_3653.jpg>`_.

.. [#pdfrm] `PDF 32000-1:2008 <https://www.adobe.com/content/dam/Adobe/en/devnet/pdf/pdfs/PDF32000_2008.pdf>`_.
