187608 - Using -moz-opacity and hover with images causes images to flicker on hover

Status: RESOLVED FIXED

(Core :: CSS Parsing and Computation, defect)

Description

[jd142]

User-Agent:       Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.2.1) Gecko/20021130
Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.2.1) Gecko/20021130

In the page at http://www.dracovolans.com/moztest.html I have images that are
anchors with an initial -moz-opacity of .5.  As the mouse moves over them they
should change to a -moz-opacity of 1 using the a:hover pseudo-element.  The
problem is that the pictures flicker and resize down to the small "missing
image" size icon as the mouse hovers over them.  Sometimes you see the "missing
image" icon, sometimes you see the image itself resized down.  If you do not
initially experience the problem close Mozilla then reopen it and click on Edit
| Preferences to bring up the Preferences window.  Click on Advanced | Cache and
clear your cache.  Click ok and then go to
http://www.dracovolans.com/moztest.html and let your mouse hover over the image.
 This has been reproduced on Windows XP and Linux, using Mozilla 1.1 and 1.2.1

Reproducible: Always

Steps to Reproduce:
1.  Open Mozilla
2.  Click Edit | Preferences
3.  Click Advanced | Cache
4.  Clear all both caches.
5.  Close and reopen Mozilla
6.  Open http://www.dracovolans.com/moztest.html
7.  Move your mouse over the images

NOTE:  Steps 1-5 not necessary on all computers.  

Actual Results:  
Images flicker, resize, disappear

Expected Results:  
Mozilla should have changed the opacity of the images without attempting to
resize them in any way.

As I stated in other places, some people saw the problem immediately, some
didn't see it.  All those who initially didn't see the flickering experienced
the problem after clearing their cache and reloading.

Comment 1

[Boris Zbarsky [:bzbarsky]]

This is caused by the reframe when opacity changes to 1.0... using 0.99 instead
should help in the short run.

In the long run, do we want to just not reframe if something with opacity !=1
changes to be fully opaque?  Why not let it keep its view?

Comment 2

[Christian :Biesinger (don't email me, ping me on IRC)]

I believe this is a duplicate of bug 187247...

Comment 3

[Boris Zbarsky [:bzbarsky]]

It's not.

Comment 4

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

Here's what I'm going to do:
-- let it keep its view
-- make view creation not require a reframe (just reparent some views in the
view tree instead)
-- create a view when we get a SyncFrameView hint for a frame without a view
that needs one
-- then style changes that may need views created won't need to ever ask for a
reframe, so all that crappy logic can be deleted

Comment 5

[Dave Fennell]

I just tried this with Mozilla 1.3b Mozilla/5.0 (Windows; U; Windows NT 5.0;
en-US; rv:1.3b) Gecko/20030119

And it worked beautifully...really nice effect.

My setup is W2K, DirectX9, NVidia TNT2

Comment 6

[Boris Zbarsky [:bzbarsky]]

To roc per comment 4.

Comment 7

[Pascal Chevrel:pascalc]

Can't reproduce it with build 2003051204 WinXP

Comment 8

[José Jeria]

WFM Gecko/20030821, Windows XP

Comment 9

[jd142]

Even though I initially submitted this, I don't think I can close it.  But I
don't know enough about Bugzilla to be sure.  Anyway, from everything I can see
this appears to be fixed in later builds, so this should be closed as far as I'm
concerned, and I started the report.

Comment 10

[Martijn Wargers (dead)]

*** Bug 270992 has been marked as a duplicate of this bug. ***

Comment 11

[Martijn Wargers (dead)]

*** Bug 300521 has been marked as a duplicate of this bug. ***