> BTW, the AI we added did not use neural nets or deep learning.

So proper old-school AI then? Perl and regexes?

We took a rule-based approach, coupled with some heavy-duty statistics.

That’s “AI” alright.

I didn’t mean any disrespect. My comment was meant to be humorous.

As was mine.

(Have you _seen_ the internals of Perl's regex code? I swear it has more inexplicable random interconnectedness than most neural nets...)

That must be an amazing feeling! Is this a feature that's still in macOS today? Can I see it in action?

The feature is there. I assume our code is still used, but it may have been rewritten since I retired. You can use this as an example if you like: https://www.extension.purdue.edu/extmedia/FNR/FNR-269-W.pdf

(which is random, but you need two columns in the PDF). Try select from column 1 near the bottom, across to column 2.

PDFs are very diverse. Our algorithm does not always work, alas, but it is significantly better than what existed before.

In fact, for some reason, it works well for this document on page 1 and 3 but not so well on page 2! But I no longer have access to the low level tools I used to use to figure out what went wrong.

This is so neat. Like someone else mentioned already, this feature has been very useful for me countless times. In fact, when it doesn't work, I tend to blame the PDF itself :). Thanks a ton!

Yup, just open Preview for an image (possibly other documents as well e.g., PDF), go into “markup” mode, and begin to draw with the pen or pencil. Preview will try to “perfect” your drawn check mark, X, straight line, curved line, etc.

That's a nice feature! But it was added after we left Apple. I cannot claim any credit for it.

That's a different "smart" feature -- the one mentioned has to do with guessing where the selected text continues (when it goes on to a different column, text box, etc).

PDFs are more "baked" layouts rather than high level semantic markup, so it's not easy to automatically determine this. The AI is probably a set of heuristics.

I remember this being introduced, and thought ‘that’s cool’. I use that function in Preview most days so - thank you.

And then Apple went and borked Preview by rewriting it post-Mavericks. Used to keep a VM just for it. Not sure why they decided to "fix" something that wasn't broken but to this day Preview lacks a lot of functionality it once had.

Just a bit of an aside. I'm still somewhat bitter about it :-p

This might explain a bug that's been bugging me for years: text selection in preview tends to fail when working with PDFs printed from Firefox (and others). The selection jumps from the cursor and includes too much text from below. If I select from below it jumps and selects from above. Not just words, but sometimes entire extra sentences or paragraphs.

This is quite similar to iOS text selection in practice: mostly works, but when it doesn't you're screwed.

Very interesting! Also a great reminder that AI is just a program that solves a problem in a certain way that may not need the most talked-about techniques, like deep learning.

Just to confirm, are you the person the changed the Preview PDF text selection in newer macOS versions? o_0

We created a low-level framework that was used by PDFKit (and hence by Preview) to change the way selection of text in PDF documents is done. We never worked on Preview itself. Since the feature is part of PDFKit, it is also available to third-party apps that use PDFKit.

I remember that! It's such a great feature!

Unfortunately it doesn't work correctly for the PDFs I get from my accountant.

It's one of those features that are really obvious, but probably surprisingly hard to implement.

I know you.

haha, I think I know who you are (though I don't _know you_) .. developer of Glider and Pararena, among others? :) If so, thank you for making such fun and memorable games!

You are correct.