PDF without Adobe: 9 Bizarre bug in macOS

If you’ve been looking at my PDF reader app Podofyllin, or the demo reader which I have built on here and provided in source code, you may have noticed their rather strange behaviour. Open two or more PDF documents at once, and try navigating around one of them. As you scroll down and the thumbnail view advances pages, every open PDF document does the same thing. Yes, they scroll in synchrony – different documents in separate windows.

If I had wanted to do that deliberately, it would have been quite a coding challenge. In this case, it’s just a bug, apparently.

What is happening is that, when the PDFThumbnailView signals that it’s going to change pages, every other PDFThumbnailView responds likewise. Normally, that signal would only affect the PDFThumbnailView of the current PDFView, but because of a coding error probably inside the Quartz Framework, all the views respond in unison.

I’m looking at how best to work around this. Other apps now seem to have rolled their own PDFThumbnailViews because of other bugs which have plagued it since macOS Sierra. That may be my best solution too.

For the moment, what I have changed in Podofyllin is to make thumbnail views an option. If you’re only going to have a single PDF document open at a time, and want to see its thumbnails, you can leave the new Show Thumbnails item in its app menu ticked. If you’re going to open two or more documents at the same time and don’t want them to page up and down in synchrony, then untick that menu command, and they’ll open without thumbnail views.

Regardless of that bug, I have now produced another version of Podofyllin for you to use. This includes many of the suggestions that you made for additional features, but doesn’t yet offer searching within the PDF itself. That will come soon, I hope. This version is 1.0b3, as I had the unreleased 1.0b2 notarized ready for release before I implemented the workaround for this bug.

The following are the other major changes:

  • The text view now provides word and character counts at its foot.
  • A new Go menu provides commands, with keystroke shortcuts, to move forward and back one page, and to go to the start or end of the whole document.
  • To remove a conflict with other commands, those to change the font size in the text view are different.
  • The View menu now has three commands to control zooming for the PDF document, which let you zoom in and out, and restore the normal auto sizing behaviour.
  • The Help menu now has my usual link to updates here, and a new PDF Help book, which is also provided separately.
  • The default window sizes have been increased.

Apart from this strange linkage between different document windows – which only becomes manifest when you have two of more windows open – I hope that you find this a great improvememt.

Podofyllin 1.0b3 is available from here: podofyllin10b3
and from Downloads above.

It’s worth trying, even if just to experience this weird synchronised scrolling! If you are using the PDF reader demo app which I posted here and want me to explain how to implement this workaround in that, let me know. It’s not hard, just requires a little ingenuity.