Preview in macOS Big Sur is destroying PDFs

Post by tonyedgecombe » Wed, Dec 16, 2020, 9:32 PM UTC

zepto wrote: post #56

function_seven wrote: post #31

Earlier quoted context omitted.

> It really isn’t Apple’s fault if someone else is producing bad files that they happened to previously tolerate, especially if that somebody isn’t maintaining their software. I think it is. Preview used to correctly handle the thing, and now it doesn't. Users cannot be expected to inspect the raw PS code of their PDFs to determine standards compliance. What they can do is assume that something that works yesterday,…

Yes, it is in principle possible that Apple was doing something special to support bad PDFs produced by ABBY which they then removed. If this is what happened, I would agree with you. But, there is no evidence yet that they removed anything. It’s quite possible (I’d say likely) that ABBY’s PDFs were corrupt all along. Preview may have tolerated them not because of a special feature which was then removed, but because…

Post by matrixagent » Wed, Dec 16, 2020, 9:33 PM UTC

avalys wrote: post #23

This is a clickbait, sensationalist headline. “Saving a PDF with Preview in Big Sur can corrupt OCR text added by a third-party program” is more accurate.

Post by tonyedgecombe » Wed, Dec 16, 2020, 9:35 PM UTC

duskwuff wrote: post #127

mhh__ wrote: post #11

Preview seems like a good example of something that's worth open sourcing. Not only will people end up doing work for you, you get eyes on the code and more direct issue tracking. Consumers get a product and they still have to go on Mac to use it.

For what it's worth, Preview is a relatively thin shell around Apple's own PDFKit: https://developer.apple.com/documentation/pdfkit Whether that could itself be open-sourced is an interesting question. (My concern would be that parts of it might be covered by Adobe NDAs.)

Post by zepto » Wed, Dec 16, 2020, 9:35 PM UTC

duskwuff wrote: post #119

zepto wrote: post #78

Earlier quoted context omitted.

PDF’s are essentially a stack machine based program. It’s not clear what’s causing the problem, but verifying correctness of programs is not a solved computer science problem.

PDF is not a stack machine. This is a common misconception. PostScript was a stack machine with included operators which implemented a set of vector graphics commands. PDF has a similar rendering pipeline, but it renders a set of primitives described directly in the document -- there is no virtual machine involved.

Post by cjsawyer » Wed, Dec 16, 2020, 9:38 PM UTC

ernst_klim wrote: post #136

systemvoltage wrote: post #36

Earlier quoted context omitted.

PDF is one of the best things IMO - it's like a docker container for documents. The way the original authors intended it to be, including fonts and all the things that go into making a document. For example, I personally like to purchase books that are in PDF format, not epub/mobi. I want to rely on professional typesetting from the publishers, not some front-end engineer's vision of what the ebook should look like a…

> I personally like to purchase books that are in PDF format, not epub/mobi PDF is abysmal for books though. 1) You can't scale fonts to fit various screen sizes. 2) It's waaay more expensive to interpret and render, so it affects battery life.