I'm doing some work with OCRing PDFs, and I'm curious if there is a way to check if a PDF has been exported from Word (or Google Docs). I can check if the PDF has been OCR'd with Xpdf's pdffonts. I know Word and Google Docs automatically OCR the exported PDFs, so if I find that the PDF hasn't been OCR'd. I know it hasn't been exported. But if it has been OCR'd, is there any way to check if the PDF was exported from Word/Google Docs VS simply OCRd with a program like Tesseract? Specifically I'm working in JavaScript but any information is useful.
For anyone looking this up, what I am doing now is using pdfinfo (from Xpdf) with the -meta flag to check if the PDF has XMP metadata. PDFs exported from Word and Google Docs do not have this metadata, but other PDFs do.
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I have a PDF file with other PDF files attached to it. Acrobat shows them in "Attachments" tab and allows to open them in turn.
QPDF documentations says something about extracting attachments but I failed to find any particular commands that do that.
Is it possible to extract these attachments and have them stored on the disk as separate PDF files?
UPDATE: Just a notice to explain better what you can see in the UI: "Attachments" tab was present in older versions of Acrobat, as well as a special page of the container document recommending to download newer version of Acrobat (this page seems to be really existing as it is shown in other viewers as well as on preview image). Latest versions of Acrobat (Reader) skip this page and get you to the first attached document, with the list of all attachments shown on the left side of the screen.
I found an old GitHub issue which a little bit clarify the possibilities of attachment extraction.
It is possible to extract attachments from PDF files using the qpdf
library by understanding the PDF file structure and pulling the
attachments out "manually" by knowing which objects to extract. There
is nothing in the public API at the moment nor in the command-line
tool that enables you to work with attachments as a first-class thing,
but there is an item in the TODO list, and there is some private code
used internally to detect cases where attachments are encrypted
differently from the rest of the file. The main reason, aside from
lack of time, that attachments are not more directly supported is
because there have been various ways that they are stored in the file,
and I don't know whether I have examples of all of them. I'm reluctant
to add a feature for attachments that may miss some attachments in
some older PDF files.
https://github.com/qpdf/qpdf/issues/24
So, it seems it is possible but you should examine the details of the pdf file.
Starting with qpdf 10.2, you can work with file attachments in PDF files from the command line. The following options are available:
http://qpdf.sourceforge.net/files/qpdf-manual.html#ref.attachments
I wasn't able to find anything on the internet and I get the feeling that what I want is not such a trivial thing. To make a long story short: I'd like to get my hands on the underlying code that describes the PDF document of a selected area from a .pdf file. I've been looking for libraries or open source readers but couldn't find anything useful yet.
Does there exist something that might be able to accomplish my needs here or anything that might be reused (like an open source reader) to get there a little faster and not having to write everything from scratch?
You can convert a whole PDF document to PostScript using pdftops, one of the utilities from the poppler PDF rendering library.
This utility enables you to convert individual pages, which is at least a start.
If you just want to extract bitmapped images, try pdfimages from the same package. This extraction can also be restricted to individual pages.
The poppler library was originally written for UNIX-like systems, but there are a couple of windows builds available.
The open source tool from iText called iText RUPS does what you want, showing you all the PDF commands for a particular PDF and allow you to visualize the structure and relationships.
http://sourceforge.net/projects/itextrups/
I have been sent versions of "packed PDF" files where the top-level PDF contains child PDFs.
The top-level PDF acts primarily as a container. The packing is not always evident in Adobe reader (e.g. when pdftk is used to pack the link does not show). I can find little by Googling for this term nor in my 2012 book ("Whittington", "PDF Explained", O'Reilly).
Is this a standard part of PDF? If so I'd be grateful for pointers. And can PDFBox analyze it?
Concerning your question whether using PDF as a container file format is a standard part of PDF:
Yes, it is. ISO 32000-1:2008 describes it in section 7.11.4 Embedded file streams.
Most prominent are files associated to some document page, see 12.5.6.15, File Attachment Annotations, and those associated with the document as a whole through the EmbeddedFiles entry (PDF 1.4) in the PDF document’s name dictionary (see 7.7.4, Name Dictionary).
#JesseGood's link to PDF File Specification on the PDFBox site explains how to deal with the latter ones.
I'm not very knowledgeable concerning PDFBox and, therefore, don't know whether it allows easy access to the other kind of attachments, too. If it does not, you will essentially have to iterate the annotations of all pages to find the file attachment annotations and handle the contents according to the PDF specification.
Someone knows how can I create one pdf file from multiple ppt files ?
Whether it to write script or computer program. However if it can be done with some program it will be the best.
I searched the web for something like this but I didn't get any results.
If you want to convert the PPT/PPTX files to PDF and then join those converted PDF files into a single PDF using either .NET or Java, you may try Aspose.Slides and Aspose.Pdf.Kit components.
Aspose.Slides allows you to convert the PPT/PPTX files to PDF and Aspose.Pdf.kit allows you to join the PDF files into a single PDF. Please see if this solution can work for your scenario.
Disclosure: I work as developer evangelist at Aspose.
I was wondering if it is possible to programaticaly create a PDF file with an acceptable quality for the production press, ideally using only open-source libraries.
Right now the process is like this:
-create texts and images
-merge them into a postscript file
-use Acrobat Distiller to convert it to PDF (Acrobat distiller helps you check all the parameters of the PDF)
-send the PDF to the press
What I want is something like:
-take all texts and pictures in this folder
-encode them into the press-ready PDF, something similar to what Distiller produces
-send them to the press
How would you do that?
Many thanks...
Are the Ghostscript's gsdll32.dll and gswin{32,64}.c.exe with their source code and the GPL3 enough (or too much) of Open Source? They ship as part of all recent releases (newest one currently: v8.71).
Ghostscript can create very good quality PDF. See here for the most recent documentation about its PDF/A and PDF/X support.
Note, that this documentation until very recently was a bit misleading: it missed hinting at the requirement to edit+adapt the referred PDFA_def.ps or PDFX_def.ps templates. If you followed the old documentation without editing the templates to specifically point to the ICC color profile you wanted to embed, your output would be valid PDF, but would not pass all checks testing for compliancy with the official PDF/A+PDF/X standards.
You can generate pdfs using f.e. TeXML and XeLaTeX (first one to make scripting easier -- TeX has lots of quirks in syntax).
I also tried OpenJade and its DocBook support, but the quality was lower. TeX seems to do typesetting much better.
Both ways are using standalone programs... which you can use in shell scripts or call using system facilities.
You didn't mention which version of Distiller you're using. Recent versions do have a setting that lets you generate (different verions of) PDF/X. See also the *.joboptions files which ship with Distiller.