Site Map - skip to main content

Hacker Public Radio

Your ideas, projects, opinions - podcasted.

New episodes Monday through Friday.


hpr2771 :: Embedding hidden text in Djvu files

Part 2 of Klaatu's Djvu mini series

<< First, < Previous, , Latest >>

Hosted by Klaatu on 2019-03-18 is flagged as Clean and is released under a CC-BY-SA license.
pdf, ebook, bloat, djvu.
Listen in ogg, spx, or mp3 format. | Comments (0).

general.

To embed text into a Djvu file, you must create a djvused script detailing the page and bitmap location of one of: character, word, line, paragraph, or region.

For good measure, you should first list the contents of your Djvu bundle:

$ djvused -e 'select; ls' test.djvu
   1 P   177062  p0001.djvu
   2 P   199144  p0002.djvu
   3 P    12323  p0003.djvu
   4 P    57059  p0004.djvu
   5 P    96725  p0005.djvu
   6 P    53868  p0006.djvu

Then define the location of text in a file called, for instance, content.dsed. Assume that my page is 1000 px by 1000 px:

select; remove-ant; remove-txt

select "p0004.djvu" # page 4
set-txt
(page 0 0 1000 1000
 (word 100 600 450 800 "Hello" )
 (word 100 600 450 800 "world" ))

.

select "p0005.djvu"
set-txt
(page 0 0 1000 1000
 (line 100 400 900 600 "Hacker Puppy Radio"))

Apply this script to your Djvu file with dvjused:

djvused -f ./content.dsed -s test.djvu

Converting from PDF to Djvu

You can convert PDF files to Djvu with the djvudigital command. Due to license incompatibility, it does require you to compile a Ghostscript plugin, but it's an easy build. Get the gsdjvu code, and then follow its README instructions.

Once you've built the Ghostscript driver, you can convert PDF to Djvu:

djvudigital --words foo.pdf foo.djvu

Comments

Subscribe to the comments RSS feed.

Leave Comment

Note to Verbose Commenters
If you can't fit everything you want to say in the comment below then you really should record a response show instead.

Note to Spammers
All comments are moderated. All links are checked by humans. We strip out all html. Feel free to record a show about yourself, or your industry, or any other topic we may find interesting. We also check shows for spam :).

Provide feedback
Your Name/Handle:
Title:
Comment:
Anti Spam Question: What does the P in HPR stand for ?