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New Ghostscript PDF interpreter

ghostscript.com

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Re: New Ghostscript PDF interpreter

#91

Post by noir_lord »

hnick wrote: post #75

Because Acrobat will open these files, there is considerable pressure for Ghostscript to do so as well, though we do try to at least flag warnings to the user when something is found to be incorrect, giving the user a chance to intervene. Anyone who has done PDF composition for a "print ready" job (what a lie) from a client has run into this so many times. All we have to do is rearrange the pages in the right sorted…

Many years ago I worked in print (mostly RGB to CMYK stuff, small run) and the very expensive RIP software chocked on what seemed like every PDF a customer supplied.

I ended up with a fairly large set of shell scripts over Ghostscript to convert them into high DPI tif's to be able to reliably print them, it worked remarkably well considering that one was open source and free and the other was 1000's per license.

Re: New Ghostscript PDF interpreter

#92

Post by sebras »

kisamoto wrote: post #45

Not sure why this is being posted now as this is from March... But anyway - I understand why they have changed their interpreter however the lack of major version bump threw me off. I use ps2pdf to optimize pdfs (long story short - makes their size smaller) and was alarmed when my pdfs suddenly ended up without the jpeg backgrounds. Instead, purely black (although this did result in a very small file size so who know…

Do you mind reporting this over at https://bugs.ghostscript.com/ ? I work on MuPDF myself, but I'm sure my colleagues working on Ghostscript would want to have any differences fixed. Thank you! :)

You can also reach us developers over at our ghostscript Discord channel https://discord.gg/H9GXKwyPvY (https://discord.gg/SnXWzqzjKs for mupdf).

Re: New Ghostscript PDF interpreter

#93

Post by airbreather »

neilv wrote: post #34

Years back, I raised how evolved Ghostscript had been over a very long time, together with the huge complexity of the PDF specs, as a potential source of vulnerabilities. (But maybe wasn't as much on people's radars, with all lower-hanging fruit of other technology choices and practices going on, outside of PDF.) New code for a large spec is also interesting for potential vulns, but maybe easier to get confidence abo…

More trustworthy thank Adobe...

Not hard

Re: New Ghostscript PDF interpreter

#94

Post by hnick »

noir_lord wrote: post #91
hnick wrote: post #75

Because Acrobat will open these files, there is considerable pressure for Ghostscript to do so as well, though we do try to at least flag warnings to the user when something is found to be incorrect, giving the user a chance to intervene. Anyone who has done PDF composition for a "print ready" job (what a lie) from a client has run into this so many times. All we have to do is rearrange the pages in the right sorted…

Many years ago I worked in print (mostly RGB to CMYK stuff, small run) and the very expensive RIP software chocked on what seemed like every PDF a customer supplied. I ended up with a fairly large set of shell scripts over Ghostscript to convert them into high DPI tif's to be able to reliably print them, it worked remarkably well considering that one was open source and free and the other was 1000's per license.

Yeah you just moved the RIP upstream, rasterize before the rasterizer :) We did that for a few jobs that caused trouble.

I haven't worked on the innards of those machines but my suspicion is that it's a combination of 1) Not much RAM, to keep costs down, 2) An inability to handle a large number of resources i.e. no swapping out to slow storage on a least-recently-used principle or similar, and 3) extremely strict conformance to avoid surprises in output.

Re: New Ghostscript PDF interpreter

#95

Post by PoignardAzur »

aidos wrote: post #6

Does anyone know much about the Artifex team? How big it is etc? They seem to be the kings of working with PDFs. I’ve not really looked at the Ghostscript code (and I’m surprised to hear their interpreter was still in postscript), but I’ve looked through the mupdf code and what I saw was really nice. In any case, I appreciate the work they’ve done in providing fantastic tools to the world for decades now.

Currently working at Artifex.

AFAICT, it's roughly 30 people, mostly seniors.

> but I’ve looked through the mupdf code and what I saw was really nice.

It is! Best onboarding experience I've ever had.

Re: New Ghostscript PDF interpreter

#96

Post by sandstrom »

sebras wrote: post #92
kisamoto wrote: post #45

Not sure why this is being posted now as this is from March... But anyway - I understand why they have changed their interpreter however the lack of major version bump threw me off. I use ps2pdf to optimize pdfs (long story short - makes their size smaller) and was alarmed when my pdfs suddenly ended up without the jpeg backgrounds. Instead, purely black (although this did result in a very small file size so who know…

Do you mind reporting this over at https://bugs.ghostscript.com/ ? I work on MuPDF myself, but I'm sure my colleagues working on Ghostscript would want to have any differences fixed. Thank you! :) You can also reach us developers over at our ghostscript Discord channel https://discord.gg/H9GXKwyPvY ( https://discord.gg/SnXWzqzjKs for mupdf).

Will this new PDF interpreter also go into MuPDF? For use in e.g. `mutool draw`

Re: New Ghostscript PDF interpreter

#97

Post by PoignardAzur »

mkl wrote: post #50

> As time has gone on, and we have encountered more and more PDF files with ever more unexpected deviations from the specification Does anyone know of a collection of malformed PDF files? It would be useful for testing PDF processing programs.

Artifex has a public suite of PDF files here:

http://git.ghostscript.com/?p=tests.git;a=tree;f=pdf;h=2ce4f...

They're not all malformed, and they're mostly used for snapshot testing, but they cover a wide range of corner cases.

Re: New Ghostscript PDF interpreter

#98

Post by lvh »

POPOSYS wrote: post #79
lvh wrote: post #17

Earlier quoted context omitted.

We (Latacora) previously advised clients to encapsulate GhostScript processing in something with a hard security boundary (like a Lambda) and I am not expecting the new implementation to change that.

Is this AWS Lambda or what kind of "Lambda" is this about?

Yep, AWS Lambda.
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