1696334 - Printing emails from gmail generates blank pages instead of content

Status: VERIFIED DUPLICATE of bug 1648947

(Core :: Printing: Output, defect, P3)

Description

[Katelyn Gadd (:kael)]

If I use the 'print' option in gmail to print some of my emails, in some cases the firefox print preview shows multiple blank pages. If I print those pages to PDF they're blank in the pdf too. Printing the same email in Edge works. I tested saving the print page as HTML from firefox, and the saved HTML has the same problem. There's nothing particularly complex about this HTML, so I'm not sure what kind of bug could be causing this, but it's very severe - data-loss level, since this makes it impossible to print out stuff or archive it as a PDF/XPS and it looks like it's working at a glance.

I can provide the HTML file but it contains personal information so I'm not attaching it to the bug. I am attaching a screenshot showing a side-by-side where you can see the blank page issue, though.

Comment 1

[Katelyn Gadd (:kael)]

Attachment: image.png

Comment 2

[Emilio Cobos Álvarez [:emilio]]

Is there any chance you could maybe post the saved html with the personal data stripped out? That might simplify figuring this out. Also, is this any better if you change the layout.display-list.improve-fragmentation pref in about:config?

Thanks!

Comment 3

[Katelyn Gadd (:kael)]

Attachment: testcase 1 (from reporter)

Changing that pref had no effect. Here's a modified version of the saved page, the bug still seems to repro for me in print preview, and it looks correct if I open it in Edge.

Note that opening this will launch the print modal, that's just how it is for these gmail pages.

Comment 4

[Emilio Cobos Álvarez [:emilio]]

Great, thanks so much! So I can reproduce the same issue at least all the way back to Firefox 48, so it doesn't seem like a recent regression...

But yeah there's something inside those nested tables which is confusing us quite a lot looks like.

Comment 5

[Daniel Holbert [:dholbert]]

Attachment: testcase 2 (reduced)

Comment 6

[Daniel Holbert [:dholbert]]

Attachment: testcase 3 (further reduced)

For me, in print preview, this testcase renders with 3 pages, as follows:

• nothing on page 1 (aside from the colorful table/cell borders which appear on all pages)
• nearly nothing on page 2, and then list items 47/48/49 at the very bottom
• page 3 is full and looks normal, aside from the fact that its first list item is #95 (so we jumped quite a bit between page 2 and page 3)

Comment 7

[Daniel Holbert [:dholbert]]

Attachment: testcase 4 (with some text added at the start)

If I add some text in a 0-height div at the start of the inner table, then we seem to print page 1 correctly, but page 2 still looks quite broken (it's mostly-empty with 47,48,49 at the bottom, and then page 3 starts with 95).

This is feeling like we're positioning the display items at the wrong offset, or something like that.

Comment 8

[Daniel Holbert [:dholbert]]

Attachment: PDF printout of testcase 3, showing the missing content

Comment 9

[Daniel Holbert [:dholbert]]

Attachment: PDF printout of testcase 2, showing the missing content (on page 2)

Comment 11

[Daniel Holbert [:dholbert]]

I suspect this is the same root issue as bug 1648947; marking as such for now. (Hopefully we can fix that one before too long, and retriage its dupes including this bug to be sure they're fixed after that point, and reopen if needed.)

Comment 12

[Ting-Yu Lin [:TYLin] (PDT, UTC-7)]

The testcase 1-4 look good in print preview after fixing bug 1648947. I verified this on Firefox Nightly 126.0a1 (2024-03-26).