Digital zines I: PDF: Difference between revisions

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<pre>mogrify -resize 120x *.JPG</pre>
<pre>mogrify -resize 120x *.JPG</pre>
== Imagemagick can do many things ==
== Thumbnails in a loop ==


See: http://www.imagemagick.org/Usage/
<pre>
mkdir -p icons
for i in *.jpg
do
echo making a thumbnail of $i
convert $i -resize 200x200 icons/$i
done
</pre>


== Make a single PDF of all the images ==
== Make a single PDF of all the images ==

Revision as of 17:17, 8 January 2020

PDF zining

Today: digital zine making with PDF (using the commandline and bash scripting)

A Zine Protocol?

In a recent blog post, titled Non-realtime publishing for censorship resistance, the author, Björn Edström, ironically(?) proposes zines as a novel new technical protocol (or “class of services”) as an alternative for traditional online publishing, which he sees as fragile and too easily censored.

The main idea is that you have one or more owners. Think of an owner as a public/private keypair. The owner manipulate (offline) a collection of files (a “zine”). This collection is encrypted, signed and published periodically. It doesn’t matter where they are published, could be anywhere on the Internet, in an actual magazine, or maybe on a Tor hidden service. It doesn’t matter.

The users can perform actions on the zine by relaying (somehow) requests to the owners. The owners may then chose to apply the action and thus manipulate/update the collection, and then publish a new collection/zine for consumption by the users. In practice they will probably have a little application for manipulating the zine, like a command line tool, text editor, or something, that handles the formatting/marshalling.

Note: Marshalling, a term with a military origin, in a techincal sense is about packaging digital stuff in a way that can be transmitted and shared. source

Post-digital

In the post, Edström is speaking to a technical audience warning of the “centralizing” tendencies and fragility of many technical solutions, despite the fact that online publishing is often portrayed as inherently decentralized. You could see this posting as part of larger contemporary phenonenon of a backlash against many of the promises of the Web and the Internet (what could be called “Web 2.0”), as, in this case, a programmer realizes that despite the conventional wisdom, for instance: the Internet being inherhently de-centralized and thus somehow impervious to censorship, and recalls that earlier technologies/media/publishing practices may in fact already have done a better job. This movement could be termed part of what’s called “post-digital”. In the case of the blog post, what’s not clear in the end however, is whether Edström is interested in the actual history of zine publishing, and whether he thinks there might be specific lessons might be taken from this already established practice.

DIY: The rise of Lo-Fi Culture, Amy Spencer

Amy Spencer’s DIY: The rise of Lo-Fi Culture (pdf) is a telling of the history of zines, which she defines as “non-commercial, small-circulation publications which are producedand distributed by their creators”.

Tom Jennings

Tom Jennings is an interesting figure at an intersection of two histories. First, he is one of the key authors of homocore, a queer zine described by Spencer. Second, Jennings is the author of the fidonet protocol and plays an important role in the history of early bulletin board systems. Jennings is featured in “BBS documentary”, a project of Jason Scott of the project archive team

bbs: baud bbs: sysops bbs: fidonet

Commandline

In addition to a certain DIY aesthetic, doing things on the commandline is quite powerful, because whatever can be accomplished once, no matter how obscure the commands or effort to get a script to work, that script can then become part of a larger program (say in a loop) and form the basis of new novel publishing workflows.

BASH Loops

BASH is the so called "Bourne again" shell -- aka the command line -- and it's a scripting language.

In programming there are only 3 imporant cases: zero, one, and more than one

When you have “more than one” thing – think loop. In BASH there are loops modelled on how they work in C. 

#!/bin/bash
for (( c=1; c<=5; c++ ))
do  
   echo "Welcome $c times"
done

You can also nest loops. It may be useful to think of a clock when nesting loops -- the outer loop is the "slower" of the two (hour hand) compared to the faster inner loop (minute hand). 

for (( h=0; h<=23; h++ ))
do

	for (( m=0; m<=59; m++ ))
	do
	echo "The time is: $h:$m"
	done

done

Concrete example: Downloading an image from online

A usefule commandline tool for downloading things that are online is wget. (See also: curl)

Let’s say we want to download all the images from homocore issue #1. They are (happily, but precariously) still available via links held in the “wayback” machine hosted by archive.org.

Downloading the images:

https://web.archive.org/web/20041020175747/http://www.wps.com/archives/HOMOCORE/1.html

Following the link: 

<https://web.archive.org/web/20041020175747/http://www.wps.com/archives/HOMOCORE/1/1.JPG>

try with wget: 

wget https://web.archive.org/web/20041020175747/http://www.wps.com/archives/HOMOCORE/1/1.JPG

Exercise: Adapt the loop code to call wget multiple times, using the variable in the command to download each page of the PDF.

Zero padding

Zero padding (or adding extra 0's to the start of a numeric filename) is a good practice as it allows numerically named files to be lexically sorted (ie alphabetically) and be in the same order as if they were numerically sorted. In other words, without zero padding, the default ordering of files (alphabetical) places "10.jpg" before "1.jpg", while "01.jpg" and "10.jpg" will sort (alphabetically) as expected. 

   printf %04d 5

outputs 

   0005

Command substitution

There are two forms: 

$(command)

and 

`command`

Source

Zero padding files after the fact

If you are unable to avoid pooly named filenames with the above, then you can fix them with the following command:

This uses the *rename* utility and regular expressions: 

rename 's/\d+/sprintf("%04d",$&)/e' foo*

Source: https://stackoverflow.com/questions/55754/how-to-zero-pad-numbers-in-file-names-in-bash#4561801

stdout/stderr/stdin

Imagemagick!

See: ImageMagick

BASH tests

https://ss64.com/bash/test.html

A looping downloader with zero-padded filenames

#!/bin/bash
for (( i=1; i<=7; i++ ))
do
	echo Starting to download issue $i...
	mkdir -p `printf %02d $i`
	for (( p=1; p<=100; p++ ))
	do  
	   outname=`printf %02d $i`/`printf %02d $i`_`printf %02d $p`.jpg
	   echo "Downloading $outname"
	   wget https://web.archive.org/web/20041020175747/http://www.wps.com/archives/HOMOCORE/$i/$p.JPG -O $outname 2> /dev/null
	   if [ ! -s $outname ]
	   then
	       echo No more pages...
               rm $outname
	       break
	   fi
	done
done

Resize all the images to be smaller

NB: the Mogrify command changes images in place (ie it destroys the originals). Just make a copy of your images first… 

mkdir originals
cp *.JPG originals

then you could: 

mogrify -resize 120x *.JPG

Thumbnails in a loop

mkdir -p icons
for i in *.jpg
do
	echo making a thumbnail of $i
	convert $i -resize 200x200 icons/$i
done

Make a single PDF of all the images

You can “bind” all the images together into a single PDF file with imagemagick: 

convert *.JPG zine.pdf

Exercise:

Create a pdf with 100 numbered pages.

PDF

Running pdfsandwich….

pdfsandwich zine.pdf

Creates zine_ocr.pdf

NB the (sub) commands it uses: 

identify -format "%w\n%h\n"  "/tmp/pdfsandwich_tmp019949/pdfsandwich_inputfilee1562e.pdf[13]"

use verbose, gives much more output!

  • Run on two images….

See pdfsandwich.log

The following is the result of running the command: 

pdfsandwich -verbose test.pdf
pdfsandwich version 0.1.7
Checking for convert:
convert -version
Version: ImageMagick 6.9.10-23 Q16 x86_64 20190101 https://imagemagick.org
Copyright: © 1999-2019 ImageMagick Studio LLC
License: https://imagemagick.org/script/license.php
Features: Cipher DPC Modules OpenMP 
Delegates (built-in): bzlib djvu fftw fontconfig freetype heic jbig jng jp2 jpeg lcms lqr ltdl lzma openexr pangocairo png tiff webp wmf x xml zlib
Checking for unpaper:
unpaper -V
6.1
Checking for tesseract:
tesseract -v
tesseract 4.0.0
 leptonica-1.76.0
  libgif 5.1.4 : libjpeg 6b (libjpeg-turbo 1.5.2) : libpng 1.6.36 : libtiff 4.0.10 : zlib 1.2.11 : libwebp 0.6.1 : libopenjp2 2.3.0
 Found AVX2
 Found AVX
 Found SSE
Checking for gs:
gs -v
GPL Ghostscript 9.27 (2019-04-04)
Copyright (C) 2018 Artifex Software, Inc.  All rights reserved.
Checking for pdfinfo:
pdfinfo -v
Checking for pdfunite:
pdfunite -v
Input file: "zine.pdf"
Output file: "zine_ocr.pdf"
Number of pages in inputfile: 2
More threads than pages. Using 2 threads instead.

Parallel processing with 2 threads started.
Processing page order may differ from original page order.

Processing page 2.
Processing page 1.
identify -format "%w\n%h\n"  "/tmp/pdfsandwich_tmpbd9242/pdfsandwich_inputfile6e1885.pdf[0]" 
identify -format "%w\n%h\n"  "/tmp/pdfsandwich_tmpbd9242/pdfsandwich_inputfile6e1885.pdf[1]" 
convert -units PixelsPerInch  -type Bilevel -density 300x300  "/tmp/pdfsandwich_tmpbd9242/pdfsandwich_inputfile6e1885.pdf[1]" /tmp/pdfsandwich_tmpbd9242/pdfsandwich8228d4.pbm
convert -units PixelsPerInch  -type Bilevel -density 300x300  "/tmp/pdfsandwich_tmpbd9242/pdfsandwich_inputfile6e1885.pdf[0]" /tmp/pdfsandwich_tmpbd9242/pdfsandwich3d8ad8.pbm
unpaper --overwrite  --no-grayfilter --layout none /tmp/pdfsandwich_tmpbd9242/pdfsandwich8228d4.pbm /tmp/pdfsandwich_tmpbd9242/pdfsandwich104659_unpaper.pbm
unpaper --overwrite  --no-grayfilter --layout none /tmp/pdfsandwich_tmpbd9242/pdfsandwich3d8ad8.pbm /tmp/pdfsandwich_tmpbd9242/pdfsandwich7570dd_unpaper.pbm
Processing sheet #1: /tmp/pdfsandwich_tmpbd9242/pdfsandwich8228d4.pbm -> /tmp/pdfsandwich_tmpbd9242/pdfsandwich104659_unpaper.pbm
convert -units PixelsPerInch -density 300x300 /tmp/pdfsandwich_tmpbd9242/pdfsandwich104659_unpaper.pbm /tmp/pdfsandwich_tmpbd9242/pdfsandwiche7f914.tif
OMP_THREAD_LIMIT=1 tesseract /tmp/pdfsandwich_tmpbd9242/pdfsandwiche7f914.tif /tmp/pdfsandwich_tmpbd9242/pdfsandwich8ddf62  -l eng pdf 
Processing sheet #1: /tmp/pdfsandwich_tmpbd9242/pdfsandwich3d8ad8.pbm -> /tmp/pdfsandwich_tmpbd9242/pdfsandwich7570dd_unpaper.pbm
convert -units PixelsPerInch -density 300x300 /tmp/pdfsandwich_tmpbd9242/pdfsandwich7570dd_unpaper.pbm /tmp/pdfsandwich_tmpbd9242/pdfsandwich33bb2b.tif
OMP_THREAD_LIMIT=1 tesseract /tmp/pdfsandwich_tmpbd9242/pdfsandwich33bb2b.tif /tmp/pdfsandwich_tmpbd9242/pdfsandwich70ba74  -l eng pdf 
OCR pdf generated. Renaming output file to /tmp/pdfsandwich_tmpbd9242/pdfsandwichd39e00.pdf

OCR pdf generated. Renaming output file to /tmp/pdfsandwich_tmpbd9242/pdfsandwichbea9bf.pdf

OCR done. Writing "zine_ocr.pdf"
pdfunite /tmp/pdfsandwich_tmpbd9242/pdfsandwichd39e00.pdf /tmp/pdfsandwich_tmpbd9242/pdfsandwichbea9bf.pdf /tmp/pdfsandwich_tmpbd9242/pdfsandwich_outputc93999.pdf

zine_ocr.pdf generated.

Done.

Unpick each command, read the man pages

unpaper --help

man unpaper

Pick apart the commands, can find the tesseract command: 

OMP_THREAD_LIMIT=1 tesseract /tmp/pdfsandwich_tmpbd9242/pdfsandwiche7f914.tif /tmp/pdfsandwich_tmpbd9242/pdfsandwich8ddf62  -l eng pdf

What does this do??

  • 1: Document each step of the process
  • 3: rewrite the process to allow editing of the files before producing the final pdf
  • 2: intervene to treat some pages differently…

evt use a makefile ?? (could be nice)

Tools

Other sources of scanned materials to choose from

Platforms

hocr2pdf

Reminder what standard in is… example pipeline. (TODO… maybe with pdftotext and grep!)

PROTIP: https://github.com/tesseract-ocr/tesseract/wiki/FAQ#how-do-i-integrate-original-image-file-and-detected-text-into-pdf

and what about this one: https://github.com/eloops/hocr2pdf and this one: https://github.com/concordusapps/python-hocr

in a python3 venv * pip install lxml # sudo apt install libxml2-dev libxslt-dev

Try adding other pages .. reordering pages…

(Eventually maybe look into pdftk)

ugh: hocr2pdf seems not to really work consistently

tools for deconstructing / editing pdf ???

todo ?! (instead of hocr) https://www.binpress.com/manipulate-pdf-python/

More bash commands like image magic to create a title page …. use pdftk or pdfunion to combine pages.

Use the scanner as input!!!!

Use scanimage (with brew ?!)

pdf2txt.py -t xml test_ocr.pdf

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