Wikipedia:Reference desk/Archives/Computing/2023 April 23

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April 23

Undo 2-up PDF

I have a PDF document that has been converted to a "2-up" format, i.e. each page of the PDF represents 2 pages of an original document, side by side. Working from the Linux command line, is there an easy way to undo that conversion and recreate the original document? --174.89.12.187 (talk) 09:25, 23 April 2023 (UTC)

The best I can think of is:

1. pop the pdf into individual one-page pdf files with PDFtk (pdftk in.pdf burst)
2. use pdfcrop to extract the left (and again the right) sub pages - see https://askubuntu.com/questions/124692/command-line-tool-to-crop-pdf-files
3. merge the resulting pages back into one, again with PDFtk (with pdftk cat)
4. you may want to rotate the pages 90 degrees (pdftk rotate

-- Finlay McWalter··–·Talk 10:46, 23 April 2023 (UTC)

A similar method to that suggested by Finlay McWalter is to use pdfseparate(1) and pdfunite(1) depending upon what your distro provides. Martin of Sheffield (talk) 11:36, 23 April 2023 (UTC)

Depending upon what is in the PDF, you might want to consider pdftext(1). There's also pdftohtml(1) and pdftops(1) which might possibly help. It's also worth having a look at the formatting of the double pages, try file page-1.pdf or similar and see if there is an easy way to split them. Martin of Sheffield (talk) 13:54, 23 April 2023 (UTC)

Thanks, folks. I should be fine from there. --174.89.12.187 (talk) 18:19, 23 April 2023 (UTC)

The tricky part was figuring out how to use pdfcrop, and I may as well write it up here in case it helps someone else. I finally learned that I had to use the option -clip as well as -bbox, and specify the bounding box as a string of four space-separated numbers in units of points measured from the left and bottom. The original pages were A5 size, which is 419.53 × 595.28 points, so I ended up using:

             pdfcrop -clip -bbox '0 0 419.53 595.28' infile.pdf leftpage.pdf
             pdfcrop -clip -bbox '419.53 0 839.06 595.28' infile.pdf rightpage.pdf

--174.89.12.187 (talk) 16:35, 28 April 2023 (UTC)

Resolved