User:Simon/Trim4/PDF imposition

PDF imposition

Premise: I will write my own script(s) to impose pages from a source PDF:

The aim is to write a Python script to automate the process by iterating recursively over pages in a PDF. These will be called in Python as subprocesses using the subprocess module.

PDF imposition from scratch

23.09.19
I'm working out which commands to use from the command line. The process should be as follows:

   #burst the source PDF, keep the name of the source plus page number (-%d)
   $ pdftk source.pdf burst output source-%d.pdf

Results:

To identify the size of a single burst page in pixels, this is the command I used:

   $ identify Carrier_burst-1.pdf 

which returns this information:

   Carrier_burst-1.pdf PDF 398x591 398x591+0+0 16-bit sRGB 19486B 0.000u 0:00.009

26.09.19
Then for the next step, resizing each page to fit 2-up on an A4. It's easy enough to reduce to 50% if the original is A4, but in other formats it's a bit trickier...

   #resize the resulting burst single page PDF (this only does one - needs Python loop to iterate recursively)
   $ magick mogrify -resize 50% new_source.pdf
   #or to resize to specific pixel dimensions such as 256x256
   $ magick mogrify -resize 256x256 new_source.pdf

After resizing to 50%, the identify command returns these values:

    Carrier_burst-1.pdf PDF 199x296 199x296+0+0 16-bit sRGB 51910B 0.000u 0:00.000

27.09.19
The next steps are these:

   #impose 2up on a page using imagemagick montage command
   #assemble imposed PDFs into a single file

Using pdfimpose

pdfimpose is a python library that does imposition. It's quite easy and powerful, though again it is not quite set up for cutting pages. I found some Python code, which creates an imposed PDF in a 2x2 format, with folds to be made first vertically, then horizontally:

   from pdfimpose import impose, VERTICAL, HORIZONTAL
   
   impose(inname=["foo.pdf"],outname="foo-impose.pdf",fold=[VERTICAL, HORIZONTAL],bind="left",last=0,)

The resulting layout for the PDF is like so:

Documentation for pdfimpose can be found here:

https://buildmedia.readthedocs.org/media/pdf/pdfimpose/latest/pdfimpose.pdf