PDF, Portable Document Format

Searching

Shawn graham suggests a pdftotext hack. First, install poppler using your choice of package manager. Now,

find /MLR -name '*.pdf' -exec sh \
  -c 'pdftotext "{}" - | grep --with-filename --label="{}" \
  --color "SEARCHTERM"' \;

Reduce bloat

PDFs have a lot of ways of storing data and many of them leave you keeping lots of crap there that you do not need for the current purpose, in the form of, presumably, inefficiently compressed images, excessively high resolution images, or miscellaneous other crap. Slimming them down to the essentials is in general complicated and context-dependent, and I do not know of a general solution. Here are some that work in some contexts.

Classic ghostrscript method:

gs -sDEVICE=pdfwrite -dCompatibilityLevel=1.5 \
  -dPDFSETTINGS=/ebook \
  -dNOPAUSE -dQUIET -dBATCH \
  -sOutputFile=output.pdf input.pdf

Wrapped up into a nice little script, ShrinkPDF: (90 is the dpi here.)

./shrinkpdf.sh in.pdf out.pdf 90

There is also cpdf and the GUI version Densify.

Commercial online PDF tool smallpdf claims to shrink PDFs also. (USD12/month with free trial.)

OCRMyPDF makes a scanned PDF possibly-searchable and also optimizes the size, optionally aggressively. This will not downsample, but it will get better monochrome compression than normal.

A peer recommendation: PDF Resizer

Concatenate/split

This ghostcript command concatenates PDFs:

gs -dBATCH -dNOPAUSE -q -sDEVICE=pdfwrite \
  -dPDFSETTINGS=/prepress -sOutputFile=output.pdf input*.pdf

You can split PDFs also with ghostscript, but usually you want a GUI to see what you are splitting, no?

PDFMix and PDF shuffler have both been recommended to me for this.

Antoine Chambert-Loir points out the underdocumented command texexec has many PDF-editing sub-commands.

The following command extract pages 1 to 5, page 7 and pages 8 to 12 from file.pdf and puts it in outputfile.pdf

texexec --pdfselect --select=1:5,7,8:12 --result=outputfile.pdf file.pdf

There is also PDFtk which has a handy command line. This ahs been ported to linux as pdftk-java and also has a gui called PDF Chain.

EPS to PDF

EPS to PDF conversion:

ps2pdf14 -dEPSCrop Logo.eps

PDF to SVG

pdf2svg generates editable vector diagrams from the PDF.

HTML to PDF

See weasyprint, below.

Diffing PDFs

The use case here is, they say, a (presumably scientific) review. “You reviewed version A of a paper, and receive version B, and wonder what the changes are.” The tool is pdfdiff.

To CMYK

CMYK Color conversion of RGB PDF with GhostScript:

gs -q -dNOPAUSE -dBATCH -sDEVICE=pdfwrite \
  -sColorConversionStrategy=CMYK \
  -sColorConversionStrategyForImages=CMYK \
  -sDEVICE=pdfwrite \
  -dProcessColorModel=/DeviceCMYK \
  -dCompatibilityLevel=1.5 \
  -sOutputFile=result_cmyk.pdf \
  your_document.pdf

See also a PDF to TIFF example.

To Greyscale

gs -q -dNOPAUSE -dBATCH -sDEVICE=pdfwrite \
  -sColorConversionStrategy=Gray \
  -dProcessColorModel=/DeviceGray \
  -dCompatibilityLevel=1.5 \
  -sOutputFile=result_gray.pdf \
  your_document.pdf

Weasyprint

Weasyprint seems the cleanest. It converts HTML+CSS into PDF, and is written in pure python. It can be used from the command line or programatically.

It is based on various libraries but not on a full rendering engine like Blink, Gecko or WebKit. The CSS layout engine is written in Python, designed for pagination, and meant to be easy to hack on.

pip install weasyprint
weasyprint https://weasyprint.org/ weasyprint.pdf

SVGlib

svglib provides a pure python library that can convert SVG to PDF, and a command line utility for same, svg2pdf. Thus one can, e.g. add SVGs to PDFs in reportlab.

Reportlab

Apropos that, reportlab is the famed monstrous classic way of programatically generating PDFs from code. It includes a modicum of typesetting. It doesn’t edit PDFs so much, but it generates them pretty well. Its integration with other things is often weak — if you thought that inserting LaTeX equations would be simple, or HTML snippets etc. On the other hand it has fancy features such as its own chart generation library. On the third hand, there are better, more widely supported charting libraries that it doesn’t use. Litmus test: Use it if the following feels to you like a natural way to print two columns:

from reportlab.platypus import (
  BaseDocTemplate,
  Frame,
  Paragraph,
  PageBreak,
  PageTemplate )
from reportlab.lib.styles import getSampleStyleSheet
import random

words = (
  "lorem ipsum dolor sit amet consetetur "
  "sadipscing elitr sed diam nonumy eirmod "
  "tempor invidunt ut labore et").split()

styles=getSampleStyleSheet()
Elements=[]

doc = BaseDocTemplate(
  'basedoc.pdf',
  showBoundary=1)

#Two Columns

frame1 = Frame(
  doc.leftMargin,
  doc.bottomMargin,
  doc.width/2-6,
  doc.height,
  id='col1')
frame2 = Frame(
  doc.leftMargin+doc.width/2+6,
  doc.bottomMargin,
  doc.width/2-6,
  doc.height,
  id='col2')

Elements.append(
  Paragraph(
    " ".join([random.choice(words) for i in range(1000)]),
    styles['Normal']))
doc.addPageTemplates([
  PageTemplate(id='TwoCol',frames=[frame1,frame2]),
])

#start the construction of the pdf
doc.build(Elements)

pdfrw

pdfrw:

pdfrw is a Python library and utility that reads and writes PDF files:

• Operations include subsetting, merging, rotating, modifying metadata, etc. […]
• Can be used either standalone, or in conjunction with reportlab to reuse existing PDFs in new ones

Here is a gentle HOWTO. You can use it to put matplotlib plots in reportlab PDFs, getting the best of two bad worlds.

Scribus

scribus is a reasonable open-source desktop publishing tool. If your content is not amenable to automatic layout out it is a good choice, for e.g. posters. It includes a Python API, albeit a reputedly quirky one, which is AFAICT Python 2. For all that, it’s a simple and interactive way of generating PDFs programmatically, so might be worth it.