Created attachment 322587 [details]
actual print preview
# Steps to Reproduce
1. Go to https://dahjelle.github.io/pdf-test/
2. Look at the print preview dialog.
# Expected Behavior
The bottom line of the PDF should not be cropped off. (See attached expected.png, taken from opening the PDF in its own tab instead of an iframe.)
# Actual Behavior
The bottom line of the PDF is cropped off.
This does not happen if you open the PDF at https://dahjelle.github.io/pdf-test/sample.pdf directly and print from there.
Created attachment 322588 [details]
expected print preview
This sounds similar to https://bugs.webkit.org/show_bug.cgi?id=57747, but I'm not sure it is related.
In Safari 10.1.2 on macOS 10.12.6, the print preview I get is just all black.
To be more clear than the drop-down menus let me be, I can reproduce this in:
Safari Version 11.0 (12604.1.38.1.7) on macOS 10.12.6
Safari Technology Preview Release 40 (Safari 11.1, WebKit 12605.1.6.0.1) on macOS 10.12.6
We originally ran across this on Safari 10, if I recall, but I don't have a copy of that handy to test.
I get a similar-but-different issue on iOS. (iOS 11 on an iPhone X simulator) Then, the output is not cropped, but instead it is shrunk and a footer placed on the bottom of the page. There, too, printing the PDF from a tab of it's own works as I'd expect.
(Please let me know if I should open a separate issue for that.)
The black preview happens when I open the link in a background tab by Cmd-clicking it, so it's a separate unrelated issue. I can reproduce the behavior that you describe, testing Safari 11 on High Sierra.