HOWTO Convert (and Rotate) Windows PDFs

I often have to swap documents in PDF format, and have lately come across a wierd problem that must be a Mac OS X misinterpretation of either PDF compression or text encoding.

Basically, PDFs generated on Windows machines (most notably those that use [Ghostscript\ variants like PrimoPDF) are unreadable in Mac OS X‘s Preview, displaying garbled text.

I still don’t know exactly why (it also happened with at least one Linux-generated PDF, to my utter bewilderment), but I’ve finally figured out how to view them correctly without installing Adobe’s (extremely) bloated Acrobat Reader on my Macs.

The one solution that worked for me was to use Ghostscript to convert the PDF files back into “raw” PostScript and then double-click on the resulting .ps file to force Preview to re-encode it into PDF format.

To do that, I got Ghostscript from Fink and used the following gs incantation:

$ gs -dNOPAUSE -dBATCH -sDEVICE=pswrite -sOutputFile=out.ps -f in.pdf

This invokes gs to batch render the input file to a PostScript file, which I then double-click to open in Preview.

If (like me) you’d rather read through a single file, here’s a nice way to join PDF files in a single converted output file:

$ gs -dNOPAUSE -dBATCH -sDEVICE=pswrite -sOutputFile=out.ps -c save pop -f \*.pdf

The save pop thing is the key here (remember PostScript is stack-based).

There’s also the option to use the pdfwrite device like so:

$ gs -dNOPAUSE -dBATCH -sDEVICE=pdfwrite -sOutputFile=out.pdf -f \*.pdf

Another useful trick is to simulate a “side by side” layout (using psnup from the psutils package) after you convert the PDFs to PostScript:

$ psnup -2 out.ps two-up.ps

You then simply open the PostScript file in Preview and rotate it – bingo, instant side-by-side layout (great for wide screens).

My favorite, however, is this one:

gs -sDEVICE=pdfwrite -dNOPAUSE -dQUIET -dBATCH -dFirstPage=m
-dLastPage=n -sOutputFile=out.pdf in.pdf

(taken from here)

Update: One of these days I’ll try Easy N-Up, which requires a working TeX install.