W3C home > Mailing lists > Public > www-style@w3.org > August 2011

Re: [css3-animations] Effect of display:none and visibility:hidden on animations

From: Dean Jackson <dino@apple.com>
Date: Mon, 01 Aug 2011 14:20:56 -0700
Cc: Jonathan Snook <jonathan@snook.ca>, www-style@w3.org
Message-id: <4AEB7F6B-F730-49B8-A5C8-038FF70ED066@apple.com>
To: Rik Cabanier <cabanier@gmail.com>

On 01/08/2011, at 2:16 PM, Rik Cabanier wrote:

> I think Jonathan was looking for a solution that removes the DIV from the flow. Setting opacity to 0 will not remove the object so it will still take up space and be part of the page's layout.
> If you have a lot of animations, this causes significant slowdowns.

But he has display:none; on the div.hidden rule.

So basically the animation should run with display:block through all keyframes, then once it is done it reverts to the non-animated style where display is none.

This could lead to some weird behaviour, such as if the animation had a delay. A lot depends on when exactly the animation starts. The spec is awful in these areas :(

Dean

> 
> Rik
> 
> On Mon, Aug 1, 2011 at 1:46 PM, Dean Jackson <dino@apple.com> wrote:
> 
> On 28/07/2011, at 10:22 PM, Jonathan Snook wrote:
> 
> > However, currently, non-transitionable properties are ignored. I'd like to suggest that this be changed and I'll give you a particular use case:
> >
> >    div {
> >        display:block;
> >    }
> >
> >    div.hidden {
> >        display:none;
> >        animation: slide-out 1s 1;
> >    }
> >
> > In this example, the hidden class is applied to a DIV via JavaScript. The problem is that by setting display:none, neither animations nor transitions will work. I would propose that non-transitionable values be allowed.
> >
> > @keyframes slide-out {
> >   0% { display:block; opacity: 1; }
> >   100% { display:none; opacity:0; }
> > }
> 
> I think if you set 100% { display: block; opacity: 0; } you'd get the effect you're looking for.
> 
> The spec should say that non-animatable properties in a keyframe value rule are applied (we agreed for transitions that non-animatable properties do actually change over time, at the end of the duration). If that's not the case then I'll fix it. If WebKit doesn't implement this then it's a bug too.
> 
> So basically, I think there is a workaround, but it might not be specified or implemented :) Hopefully others agree.
> 
> Dean
> 
> 
> 
> 
Received on Monday, 1 August 2011 21:22:11 GMT

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