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3.3 KiB
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69 lines
3.3 KiB
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.. _faq:
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Frequently asked questions
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**************************
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Why is it called pdfminer.six?
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==============================
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Pdfminer.six is a fork of the `original pdfminer created by Euske
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<https://github.com/euske>`_. Almost all of the code and architecture are in
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-fact created by Euske. But, for a long time, this original pdfminer did not
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support Python 3. Until 2020 the original pdfminer only supported Python 2.
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The original goal of pdfminer.six was to add support for Python 3. This was
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done with the `six` package. The `six` package helps to write code that is
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compatible with both Python 2 and Python 3. Hence, pdfminer.six.
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As of 2020, pdfminer.six dropped the support for Python 2 because it was
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`end-of-life <https://www.python.org/doc/sunset-python-2/>`_. While the .six
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part is no longer applicable, we kept the name to prevent breaking changes for
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existing users.
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The current punchline "We fathom PDF" is a `whimsical reference
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<https://github.com/pdfminer/pdfminer.six/issues/197#issuecomment-655091942>`_
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to the six. Fathom means both deeply understanding something, and a fathom is
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also equal to six feet.
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How does pdfminer.six compare to other forks of pdfminer?
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==========================================================
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Pdfminer.six is now an independent and community-maintained package for
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extracting text from PDFs with Python. We actively fix bugs (also for PDFs
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that don't strictly follow the PDF Reference), add new features and improve
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the usability of pdfminer.six. This community separates pdfminer.six from the
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other forks of the original pdfminer. PDF as a format is very diverse and
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there are countless deviations from the official format. The only way to
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support all the PDFs out there is to have a community that actively uses and
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improves pdfminer.
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Since 2020, the original pdfminer is `dormant
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<https://github.com/euske/pdfminer#pdfminer>`_, and pdfminer.six is the fork
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which Euske recommends if you need an actively maintained version of pdfminer.
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Why are there `(cid:x)` values in the textual output?
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=====================================================
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One of the most common issues with pdfminer.six is that the textual output
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contains raw character id's `(cid:x)`. This is often experienced as confusing
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because the text is shown fine in a PDF viewer and other text from the same
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PDF is extracted properly.
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The underlying problem is that a PDF has two different representations
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of each character. Each character is mapped to a glyph that determines
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how the character is shown in a PDF viewer. And each character is also
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mapped to its unicode value that is used when copy-pasting the character.
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Some PDF's have incomplete unicode mappings and therefore it is impossible
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to convert the character to unicode. In these cases pdfminer.six defaults
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to showing the raw character id `(cid:x)`
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A quick test to see if pdfminer.six should be able to do better is to
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copy-paste the text from a PDF viewer to a text editor. If the result
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is proper text, pdfminer.six should also be able to extract proper text.
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If the result is gibberish, pdfminer.six will also not be able to convert
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the characters to unicode.
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References:
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#. `Chapter 5: Text, PDF Reference 1.7 <https://opensource.adobe.com/dc-acrobat-sdk-docs/pdflsdk/index.html#pdf-reference>`_
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#. `Text: PDF, Wikipedia <https://en.wikipedia.org/wiki/PDF#Text>`_
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