Okular does not allow review on PDF

Problem

I sometimes use Okular to annotate a PDF using highlighting, drawing boxes, underlining or writing notes. This feature is called review in Okular. However, I noticed that this review feature is disabled on certain PDF files. I did check the filesystem and the file was not readonly.

Solution

Turns out that when a PDF has DRM options set in it, Okular obeys those limitations by default. Thankfully, this can be turned off easily. Go to Settings → Configure Okular → General and uncheck the Obey DRM limitations option. You will need to restart Okular after you apply this. You will now be able to review the PDF.

Tried with: Okular 0.24.2 and Ubuntu 16.04

Okular

Okular is a fantastic application to use for viewing and annotating documents like PDF and ebooks.

  • Okular is written using the KDE framework, so expect its installation to be heavy:
$ sudo apt install okular
  • It supports viewing a whole bunch of formats for viewing: PDF, DjVu, EPUB, TIFF, CHM and other ebook formats.
  • By default, the backends for the non-PDF formats are not installed. To get them:
$ sudo apt install okular-extra-backends
  • There is full zoom-in, zoom-out, continuous or separated page viewing options.
  • Table of contents are shown for ebooks, PDF and DjVu files that have it.
  • Thumbnails of current and neighboring pages can be viewed.
  • Okular uses a printing backend that is different from the one used by Evince, the default document viewer in Ubuntu. So, if you have printing problems in Evince, try Okular.
  • Annotating documents by adding notes, highlighting and freehand is easy.

Tried with: Okular 0.19.3 and Ubuntu 14.04

How to extract original document from Okular document archive

If you annotate documents using Okular, you might be saving the file as a document archive. This is typically a file with extension .okular.

  • The document archive file is actually a zip file with 3 files inside it. First is your original document (PDF, DjVu or other format) with its original filename. The other two files: content.xml and metadata.xml hold information about your file and its annotations.

  • Okular does not provide any user interface to extract out the original document. But since we know it is a zip file, we can open the .okular file using any unzipping tool and extract out the original document! 🙂

Tried with: Okular 4.13.3 and Ubuntu 14.04

How to annotate documents using Okular

Okular is not only a great viewer for documents, but it can also be used to annotate and take notes on these documents. This is typically used with PDF documents.

  • If you want to work with DjVu and other formats, remember to install those backends:
$ sudo apt install okular-extra-backends
  • To annotate, open the document and choose Tools -> Review. The keyboard shortcut for this is F6.

  • A sidebar appears with buttons to add popup notes, freehand, highlight and other operations.

  • Single-click on any of these buttons, to be able to perform that operation once. To perform it again, you will need to click the button again.

  • Double-click on any of these buttons, to be able to perform that operation multiple times. Press Esc to disable the operation after you are done.

  • To edit the color, thickness or any other property of these annotation tools, right-click anywhere in the sidebar and choose Configure Annotations.

  • To remove any annotation (even from a PDF file), right-click on it and choose Delete.

  • To move annotations such as popup notes, hold Ctrl key while you click and drag them with the mouse.

  • By default, the annotations are saved locally in a hidden file in the home directory.

  • To save the annotations along with the file, save it as a Okular document archive. To do this, choose File -> Export as -> Document Archive. This is typically saved with the file extension .okular.

Reference: Annotations documentation page about Okular

Tried with: Okular 4.13.3 and Ubuntu 14.04

Evince not printing some pages of PDF

Problem

Evince, known as Document Viewer in Ubuntu, is a PDF viewer program. When printing certain PDF files, I notice that Evince does not print some of the pages. For a problematic PDF file, this problem happens with any printer and even with the Print to File option! I am guessing that this problem is the same as the one documented in this bug.

Sometimes, I get this error printed on the last page:

ERROR:
typecheck
OFFENDING COMMAND:
known

Solution

I am guessing that this problem is caused due to a bug in the printing backend, maybe in CUPS. So, I open such PDF file in a PDF viewer with a different backend, like Okular.

Okular can be installed easily:

$ sudo apt install okular

When I print from Okular, the PDF is printed correctly! 🙂

Tried with: Evince 3.4.0, Okular 0.14.3 and Ubuntu 12.04 LTS

Cannot print duplex from Okular

Problem

Okular is a PDF viewer for the KDE platform. When printing a PDF from Okular, duplex printing (printing on both sides of a sheet) can be enabled in the Options section for a chosen printer. For a printer that has duplex support (for example, HP Color LaserJet 4700), Okular shows this duplex printing section as disabled. So, I am not able to print duplex to this printer from Okular. Other duplex printers (for example, HP Color LaserJet Enterprise CP4520) show up with this section enabled in Okular.

Solution

I could not figure out why this problem happens. I am guessing it has something to do with the printer driver and its communication with the printer backend used by Okular.

In any case, I was able to print by opening the PDF using Evince, which is known as Document Viewer in Ubuntu. The print dialog in this had the duplex option for the same printer and I was able to print it.

Tried with: Evince 3.4.0, Okular 0.14.3 and Ubuntu 12.04 LTS