Open Bug 934081 Opened 12 years ago Updated 3 years ago

Page background image cut off on long pages (around 7000px?)

Categories

(Core :: Graphics, defect)

Product:
Core
Component:
Graphics
Version:
25 Branch
Platform:
x86
Windows 7
Type:
defect

Tracking

()

People

(Reporter: netrolller.3d, Unassigned)

References

(
URL
)

Details

On publicshaming.tumblr.com (quite long pages), as I scroll down, the background image gets cut off around 2/3rds In Firefox 24, the background turns black from that point on, while in Firefox 25, the fallback background color is drawn (instead of the image). Around glyphs, the real background image "bleeds through", i.e. alpha composition appears to be taking the background image into account even when the bug hits. Steps to reproduce: Open the attached URL, and scroll down to the bottom. Eventually, the background image will go missing. (Note: You may have to try different page numbers instead of 5 in the URL, as more posts come in - not all pages are long enough for the bug to show up.)
Component: Layout: View Rendering → Graphics
I cannot reproduce the issue with any of the links in that bug. Also, the cutoff is not sharp - the background first shows missing bands, then completely disappears as I scroll down. Sometimes, scrolling up and down moves the cutoff slightly on repaint.
Summary: Page background image cut off on long pages (32Kpx?) → Page background image cut off on long pages (around 7000px?)
Cutoff is not at 32Kpx, but around 7000px. Even factoring in the DPI dependence seen in another 32Kpx bug, this is a different issue.
Has it always been that way? Or did it regress at some point?
It appears to goes back to June 2012 or earlier, as it appears to be a duplicate of bug 764857. I forget when I first saw it -- could be three years ago or more now. There aren't many websites with pages large enough to trigger the bug, but here's another one: http://perldoc.perl.org/CGI.html For me (Firefox 25, XP) the background breaks up around 60% in (around "CREATING A GROUP OF RELATED CHECKBOXES") -- this is somewhere around 30,000 pixels (related maybe to 32,767) instead of the 7000 previously suggested. I seem to recall that I've seen this on pages on my own website, which are significantly shorter, so I don't know what the trigger is. Pretty sure I've seen it in Firefox 24 in Windows 8 as well. I'll double-check this tonight from Firefox 25 in Windows 8.
(In reply to Gábor Stefanik from comment #2) > Also, the > cutoff is not sharp - the background first shows missing bands, then > completely disappears as I scroll down. Sometimes, scrolling up and down > moves the cutoff slightly on repaint. Yes this is the sort of thing I see -- for me, the background first disappears sharply at the cut-off point, but scrolling causes bands to draw in or drop out within one page-ful of the cut-off point.
Confirmed on aforementioned page in Firefox 25 under Windows 8.
Severity: normal → S3
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