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Due to pdf popularity there is a lot of demand for pdf processing tools. And the format is so complex that there are many nontrivial and creative ways to do pdf

by sieste 9mo ago

Due to pdf popularity there is a lot of demand for pdf processing tools. And the format is so complex that there are many nontrivial and creative ways to do pdf processing. That's why these "Hello World" projects usually make Top 5 on HN, and one of the upvotes is usually from me.

forgotpwd16 9mo ago
>many nontrivial and creative ways to do pdf processing They're all wrapping PDFlib and provide the same functionality.
- sam_lowry_ 9mo ago
  I am already well served by ghostscript, GIMP, Imagemagick, etc: Optimize PDF: #!/bin/bash INPUT="$1" OUTPUT="$(mktemp --suffix=.pdf)" gs -sDEVICE=pdfwrite -dCompatibilityLevel=1.4 -dPDFSETTINGS=/ebook \ -dNOPAUSE -dQUIET -dBATCH -sOutputFile="$OUTPUT" "$INPUT" mv "$OUTPUT" "$INPUT" Merge PDF: #!/bin/sh gs -q -dNOPAUSE -dBATCH -sDEVICE=pdfwrite \ -dCompatibilityLevel=1.3 -dPDFSETTINGS=/ebook \ -sOutputFile=merged.pdf "$@" And so on and so forth. Moreover, I see a webapp and I immediately assume everything I do in this app is exfiltrated and abused. I can check that the webapp advertised above is indeed local-first, but I can't be 100% sure they don't steal my data in a way I did not foresee, e.g. via websockets or cookies. Because I learnt this the hard way by being on Instagram and Gmail.
  - ptspts 9mo ago
    Your commands to process PDF with Ghostscript are lossy (they lose lots of metadata and in minor ways they also change how the PDF renders), and they produce very large PDF files.
    - x3ro 9mo ago
      Can you expand on why the produced PDF files are supposed to be larger than the originals? I've not observed that yet.
  - tedk-42 9mo ago
    You're being downvoted because not everyone has CLI access to a server and the required ghostscript binaries etc. Realistically, most 'normal users' have PDF needs like these links and we as tech people can safely give these sites to non-technical people and have confidence their data isn't being stolen on remote dodgy servers (think gas / electricity bills, invoices, bank statements etc which is a PII gold pot).
    - sam_lowry_ 9mo ago
      Server? what server? Ghostscript is available in virtually any Linux distro, on Mac with and without brew and even on Windows. I have no confidence in any website, especially the one that claims to be local-only but can technically change on a whim of the developer once it starts getting enough traffic from users. OTOH, I trust 30+ years old software sitting on on my hard drive not to phone home on every keystroke.
  - kkfx 9mo ago
    To better compress my personal preference is pdftops -paper A4 -expand -level3 file.pdf # I'm from EU, so A4 is my common paper format ps2pdf14 -dEmbedAllFonts=true \ -dUseFlateCompression=true \ -dOptimize=true \ -dProcessColorModel=/DeviceRGB \ -r72 \ -dDownsampleGrayImages=true \ -dGrayImageResolution=150 \ -dAutoFilterGrayImages=false \ -dGrayImageDownsampleType=/Bicubic \ -dDownsampleMonoImages=true \ -dMonoImageResolution=150 \ -dMonoImageDownsampleType=/Subsample \ -dDownsampleColorImages=true \ -dColorImageResolution=150 \ -dAutoFilterColorImages=false \ -dColorImageDownsampleType=/Bicubic \ -dPDFSETTINGS=/ebook \ -dNOSAFER \ -dALLOWPSTRANSPARENCY \ -dShowAnnots=false \ file.ps compressed.pdf
    - sam_lowry_ 9mo ago
      If you do `-dEmbedAllFonts=true` then probably `-dSubsetFonts=true` would also be useful. And for the rest, `-dPDFSETTINGS=/ebook` should already have most of the values that you set explicitely.

by sieste 9mo ago

forgotpwd16 9mo ago

>many nontrivial and creative ways to do pdf processing They're all wrapping PDFlib and provide the same functionality.

sam_lowry_ 9mo ago
I am already well served by ghostscript, GIMP, Imagemagick, etc: Optimize PDF: #!/bin/bash INPUT="$1" OUTPUT="$(mktemp --suffix=.pdf)" gs -sDEVICE=pdfwrite -dCompatibilityLevel=1.4 -dPDFSETTINGS=/ebook \ -dNOPAUSE -dQUIET -dBATCH -sOutputFile="$OUTPUT" "$INPUT" mv "$OUTPUT" "$INPUT" Merge PDF: #!/bin/sh gs -q -dNOPAUSE -dBATCH -sDEVICE=pdfwrite \ -dCompatibilityLevel=1.3 -dPDFSETTINGS=/ebook \ -sOutputFile=merged.pdf "$@" And so on and so forth. Moreover, I see a webapp and I immediately assume everything I do in this app is exfiltrated and abused. I can check that the webapp advertised above is indeed local-first, but I can't be 100% sure they don't steal my data in a way I did not foresee, e.g. via websockets or cookies. Because I learnt this the hard way by being on Instagram and Gmail.
- ptspts 9mo ago
  Your commands to process PDF with Ghostscript are lossy (they lose lots of metadata and in minor ways they also change how the PDF renders), and they produce very large PDF files.
  - x3ro 9mo ago
    Can you expand on why the produced PDF files are supposed to be larger than the originals? I've not observed that yet.
- tedk-42 9mo ago
  You're being downvoted because not everyone has CLI access to a server and the required ghostscript binaries etc. Realistically, most 'normal users' have PDF needs like these links and we as tech people can safely give these sites to non-technical people and have confidence their data isn't being stolen on remote dodgy servers (think gas / electricity bills, invoices, bank statements etc which is a PII gold pot).
  - sam_lowry_ 9mo ago
    Server? what server? Ghostscript is available in virtually any Linux distro, on Mac with and without brew and even on Windows. I have no confidence in any website, especially the one that claims to be local-only but can technically change on a whim of the developer once it starts getting enough traffic from users. OTOH, I trust 30+ years old software sitting on on my hard drive not to phone home on every keystroke.
- kkfx 9mo ago
  To better compress my personal preference is pdftops -paper A4 -expand -level3 file.pdf # I'm from EU, so A4 is my common paper format ps2pdf14 -dEmbedAllFonts=true \ -dUseFlateCompression=true \ -dOptimize=true \ -dProcessColorModel=/DeviceRGB \ -r72 \ -dDownsampleGrayImages=true \ -dGrayImageResolution=150 \ -dAutoFilterGrayImages=false \ -dGrayImageDownsampleType=/Bicubic \ -dDownsampleMonoImages=true \ -dMonoImageResolution=150 \ -dMonoImageDownsampleType=/Subsample \ -dDownsampleColorImages=true \ -dColorImageResolution=150 \ -dAutoFilterColorImages=false \ -dColorImageDownsampleType=/Bicubic \ -dPDFSETTINGS=/ebook \ -dNOSAFER \ -dALLOWPSTRANSPARENCY \ -dShowAnnots=false \ file.ps compressed.pdf
  - sam_lowry_ 9mo ago
    If you do `-dEmbedAllFonts=true` then probably `-dSubsetFonts=true` would also be useful. And for the rest, `-dPDFSETTINGS=/ebook` should already have most of the values that you set explicitely.