Date: prev next · Thread: first prev next last
2014 Archives by date, by thread · List index

A word of warning about text retrieved from PDF documents.

Recovering text blocks from PDFs is inherently risky. PDF is a page definition format, and so it has no notion of the semantics of the text it contains. It places bits of text at certain positions on the page. You can create a whole page of text by taking the individual characters and their attributes and position on the page, shuffling them, and writing them to the file. That will produce a readable file, but try extracting the text from that file. Unless you have a very, very smart text extractor that reverse-engineers the process of creating the page, then calculates the _visual_ order of the text elements, you will end up with gibberish.

_Most_ pdf text, _most_ of the time, is laid on the page in visual order, but in even the best-behaved files, you are likely to be surprised.

If you don't _know_ that your PDF text extractor program is completely visually accurate by design, don't tell your boss that you can easily extract that PDF text, without allowing time for proof-reading every page. You will get burned.

I don't know how LO extracts PDF text; perhaps it is very sophisticated. I have my doubts.

Peter West
"Other seed fell among thorns, and the thorns grew up and choked it..."

To unsubscribe e-mail to:
Posting guidelines + more:
List archive:
All messages sent to this list will be publicly archived and cannot be deleted


Privacy Policy | Impressum (Legal Info) | Copyright information: Unless otherwise specified, all text and images on this website are licensed under the Creative Commons Attribution-Share Alike 3.0 License. This does not include the source code of LibreOffice, which is licensed under the Mozilla Public License (MPLv2). "LibreOffice" and "The Document Foundation" are registered trademarks of their corresponding registered owners or are in actual use as trademarks in one or more countries. Their respective logos and icons are also subject to international copyright laws. Use thereof is explained in our trademark policy.