Thanks so much for your help!!
I'm using the half size and don't have any special settings. The paper size on the original PDF is 21.01 × 29.72 cm. I'm using Safari but have also tried it on Google chrome. Here is a screenshot of the print preview - you can see how every page is extending on the page below.
I think you have found a bug! It looks like the Zine Arranger doesn't work very nicely with A4 paper sizes.
I'm going to try and fix this real quick, and then I'll reply again once I have an updated version for you to try it out on & we can see if that takes care of it.
Thanks for bringing this to my attention!
Okay--I made some adjustments over on the Beta Version that I think are helping, if you'd like to try it out! Here's the link to that version: https://nashhigh.com/code/ZineArranger-1-1-Beta/
I still have some testing to do on the other v1.1 features before I'll be ready to update the itch.io version, so for now it'll probably work better to use the Beta if you're doing paper sizes other than US Letter.
And if you run into any more issues, or if it's still a problem, let me know! This one is at the funky intersection of CSS, JavaScript, and the browser's print function, so I'm not 100% confident the fix I've done so far will do the trick for all situations!
Well, darn! Does it still end up pretty much the same when you use the beta version, or is it changed at all?
I did notice in your screenshot that Safari doesn't seem to have a "Fit to Page" option, which I often have to use to get mine to work. Without Fit To Page, my little test A4 document will work at about 91%-94% Scale, although you already mentioned playing around with the scale & not having any luck with that either, so that may not be too helpful.
I wish I had Safari to test it out in! But I'll keep trying to come up with ways to make things fit better automatically, regardless of the browser--there may be some more tricks I just haven't learned about yet.
