239197 - animated gifs on :hover only played once in the page, regression

Status: RESOLVED FIXED

(Core Graveyard :: Image: Painting, defect)

Description

[Pascal Chevrel:pascalc]

Build 2004032208 WinXP

1 put an animated gif on block-level elements which are displayed with :hover
2 mouseover the blocks

expected result : the animation should be displayed every time you hover the block
actual result : the animation is only played the first time you hover the block,
if you repeat the process instead of displaying the animation, the last frame of
the gif is displayed.

This is a regression, it used to work at least until 1.6

Comment 1

[Pascal Chevrel:pascalc]

testcase added : http://pascal.chevrel.free.fr/bugzilla/bug239197/

Comment 2

[Boris Zbarsky [:bzbarsky]]

This is a result of the change in bug 57607.  This is similar to an issue we had
with setting the .src of an <img> node.   People expected that to reset the
animation too.

In this case, however, I believe that this should be wontfixed.  There are no
real backwards compat issues here (unlike .src, which has worked the way it does
for many years), and restarting the animation precisely on :hover seems like a
rather arbitrary thing to do (and in fact didn't even work if the same image was
present anywhere else on the page).

Comment 3

[Boris Zbarsky [:bzbarsky]]

Bug 210001 was the .src issue.

Comment 4

[Pascal Chevrel:pascalc]

This regression is breaking the menu animations on my site if you want a real
life example.

Comment 5

[Boris Zbarsky [:bzbarsky]]

Yes, I realize that. The point is that it's really a fluke that they worked at
all prior to the bug 57607 changes.

Comment 6

[Jamieson Christian]

I don't know if this is the place to mention it, but image animation does not
appear to be reset when switching between pages that reference the same image --
presumably if the image was cached. The image animation picks up where it was in
the last page -- or just shows the last frame in the case of a non-looping
animation that had already completed in the previous page.

Observed with Firefox 0.9. http://imperio.nightstar.ca/forum/ (Observe the
animation at the top-right, which persists on the banner as you go from page to
page. After the initial non-looping animation, it will freeze on the last frame
[totally invisible] until the navigation is interrupted by a page that does NOT
use the image.)

Should this be a separate bug?

Editorial comment: The animation behavior we're currently seeing is undesirable.
Non-looping button animations that trigger onmouseover should indeed reset to
the beginning of the animation each time the onmouseover event occurs. And if
the same image is used from one page to the next, its animation should start
over on the next page.

Comment 7

[Boris Zbarsky [:bzbarsky]]

> Should this be a separate bug?

Yes, and it's already filed.

Comment 8

[Boris Zbarsky [:bzbarsky]]

"Fixed" (as much as it ever was) by patch for bug 252730

Comment 9

[Boris Zbarsky [:bzbarsky]]

*** Bug 257662 has been marked as a duplicate of this bug. ***