61198 - fixed backgrounds don't scroll well [BG]

Status: VERIFIED INVALID

(Core :: Layout, defect, P3)

Description

[Hixie (not reading bugmail)]

STEPS TO REPRODUCE
   1. background-attachment: fixed;
      background-color: transparent;
      background-image: url(...);
   2. scroll the document

ACTUAL RESULTS
   Smudging -- we bitblt the old background before drawing the new one, and
   since the background is transparent that means we draw the new background
   atop the old one.

EXPECTED RESULTS
   Same as when you resize the window.

I shall provide a testcase in due course.

Comment 1

[David Baron :dbaron: (⌚️UTC-4, no longer working on Mozilla)]

How does this work with the new nsViewManager, which can be enabled by setting
the pref nglayout.debug.enable_scary_view_manager to true (or 1, or whatever we
use for boolean prefs)?

Comment 2

[Hixie (not reading bugmail)]

The new nsViewManager does not affect any of the fixed background scrolling bugs
that I have seen, unfortunately.

Comment 3

[Robert O'Callahan (:roc) (email my personal email if necessary)]

If you're trying to create a document that is truly transparent, then you're 
guaranteed to lose because we don't support that (yet).

I'd like to see a testcase and an explanation of what you think should happen.

Comment 4

[dcone (gone)]

I need a test case or an exact problem in order to look at and fix.  I marked as 
invald so it does not just sit in my que until a test case is made.  I am trying 
to light a fire under the the reporter so I can disposition or fix this..

Comment 5

[Robert O'Callahan (:roc) (email my personal email if necessary)]

I concur. I'm sure Ian will get back to us eventually though.

Comment 6

[Hixie (not reading bugmail)]

http://hixie.ch/tests/adhoc/css/background/bgafixed.html

VERIFIED WORKSFORME. It works now.