Comment by crazygringo | Hacker News Reader

Comment by crazygringo | Hacker News Reader

I work with a ton of PDF's between my Mac and iPad, and it mostly works but there are still just way too many bugs.

It's a lot of little things, like in Catalina where opening up the sidebar for annotations (comments) seemingly randomized their order. (Big Sur, fortunately, fixed it to be page-order again.)

Or how printing a PDF from a website (in Catalina, also seemingly fixed in Big Sur) would look right on the page... but if you copied and pasted the text from the PDF to somewhere else, something like 10% of the glyphs were scrambled ("lik3 thZs"), like some sort of character table corruption.

Or reading a PDF with Books on my iPad, maybe 10% of the time bookmarking a page... doesn't bookmark it. Or removing a bookmark... doesn't remove it. Or a handful of highlights you just made have inexplicably disappeared the next time you open the file.

Or whenever you open the PDF in Books it remembers which page you were on. Except sometimes it doesn't, so you can't really rely on that for saving your place.

Or in Books, if you select some text to copy but accidentally hit the adjacent "select all" in the pop-up menu, and you're dealing with a 400-page PDF, it just locks up and you have to restart it.

Or in Preview if you want to convert a PDF to black-and-white, there's an option for it but your PDF will balloon in filesize to 10x larger or something.

I mean, I could go on and on. It's weird, because Preview is an incredible app, really. But it really is like they build it and then never bother to test if basic workflows reliably work.

> 10% of the glyphs were scrambled ("lik3 thZs"), like some sort of character table corruption.

As I understand it, that's a form copy protection trying to prevent exactly what you're doing.

While that type of copy-protection does exist in rare instances, in this case it wasn't -- it was with any normal webpage printed to PDF. It was a straight-up bug, I tried to file it with Chromium in fact [1], but it turned out to be a macOS issue that Big Sur fixed.

[1] https://bugs.chromium.org/p/chromium/issues/detail?id=112849...

More likely it’s the effect of font subsetting.

If you want your PDF to render the same everywhere, you have to embed font information (even if that font is something like Arial, which is available almost everywhere, as ‘almost everywhere’ isn’t ‘everywhere’, and because there are zillions of variations on Arial)

You don’t want to embed entire fonts, though, certainly not if a PDF uses only a few characters of a font.

The memory wise cheapest way of embedding a font leaves out the table that maps glyph numbers back to Unicode code points. If you do that, the PDF reader guesses a 1:1 mapping to ascii/Unicode.

Subletting means you can’t extract all glyphs in a font from a single file, but AFAIK, that’s just a side effect.

I guess this bug drops such a table, or messes up that translation table.

Try to screenshot with a movie onscreen.

You get a grey rectangle.

That not remembering the last page you were at in Books drives me crazy.

My iPad would be the perfect device for reading PDF books especially technical and maths text books, if weren't for the Chinese torture of whether it will remember your page the next time you open it or will I have to scroll through until I recall where I left.

I've been a happy GoodReader user for years. Syncs with a variety of sources, remembers where I was, bookmarks work. Annotations work, but I don't use that much beyond being able to say it works.

I like the Apple Books app because

- It syncs across all my devices. No 3rd party storage like Dropbox required. In fact what I don't like is GoodReader asks for too broad an access to Dropbox/OneDrive if you try to set it up.

- Books is first party app so absolutely no tracking whatsoever. GoodReader had Facebook SDK and Google Analytics and was trying to contact a bunch of other trackers the last time I installed it.

Oh man, that was another nightmare with Books. I tried keeping syncing on for a year, but ultimately switched back to a local library.

It worked 99% of the time. But then every few weeks it would overwrite my newer-annotated version of a PDF with an older one, and I'd lose chapters' worth (in one case an entire books' worth) of highlights. It was infuriating.

It had to be some kind of iDrive sync bug. It seems insane that type of stuff passes QA, I can't even imagine.

> I'd lose chapters' worth (in one case an entire books' worth) of highlights. It was infuriating. It had to be some kind of iDrive sync bug.

That hurts, sorry to hear. iCloud drive supports files sync for files 50GB or less in size. Have you experienced sync issues with iCloud drive too? Or with Dropbox?

Nope, no data loss issues with iCloud Drive files directly (or Dropbox).

My hypothesis is that Books does something wonky with metadata for extra sync logic, like it depends on reading the last "last page read" record but then sometimes fails to write that, and then loses the pointer to the new version altogether. I can't be sure, but I can't think of any other explanation.

> GoodReader had Facebook SDK and Google Analytics and was trying to contact a bunch of other trackers the last time I installed it.

Longtime fan of Goodreader here. Sorry to hear that Goodreader is trying to contact trackers. How did you find out? Any suggestions how to prevent Goodreader to contact those trackers, eg pi-hole?

I run pi-hole with recursive dns so I was able to see what domains any app contacts and then I am able to lock it down on my local network no problem.

On my devices (iPhone / iPad) I also use Lockdown app which allows you to blacklist IP addresses and domain so once I can see what an app is up to using pi-hole, I manually add those domains to Lockdown so that even when I am out of the house the trackers are blocked.

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