RE: question about "presentation attributes"

Hi Chris,

On  Friday, March 21, 2014 at 2:12 PM
you wrote:

>Some of that is a good thing. Some of that is an unfortunate workaround of a deficiency in CSS animation (it animates only
>properties) compared to SMIL/SVG animation (it animates both attributes and properties, which requires some careful spec wording >when some properties are expressed as attributes).

>This caused a rush to make as many SVG attributes into properties as possible. Some of those were a good fit for CSS, some not.

>Web Animations is a nicely worked out harmonization of CSS Animations and SMIL/SVG animations, using a consistent underlying model >for both.
>This should reduce the pressure to make things which are clearly not suitable as properties, into properties just so they can be >animated.
>http://dev.w3.org/fxtf/web-animations/
>http://www.w3.org/TR/web-animations/

Thanks, Chris. It is starting to make a bit more sense, so I am thankful for people's patience.

In the second of these references, it says "There are a number of SVG attributes which do not map to CSS properties but which are nevertheless animatable. The procedures for animating these attributes are defined in a forthcoming SVG Animation specification."

Is the first of those references, the very same forthcoming document? I wasn't sure where the issue was addressed.

The reason I ask about these matters is that I am working on (for WebAt25) some fairly fun animations. 
http://cs.sru.edu/~ddailey/fading/slides/transitions.html

These involve animating href, as a slideshow is displayed. The inter-image transitions use a pretty broad smorgasbord of SVG effects: masks, dynamic gradients, filters, sliding geometry, transforms, keyTimes, begin, and even <random> and <replicate> and the modification of timing variables declaratively (I knew ya'll would love that!). I've put together about 50 of these effects over the past four weeks. Using SMIL, the typical effect takes between 15 and 30 minutes to assemble (when my thoughts are clear). 

Initially, I tried doing the work in JavaScript, since I wanted it to work in IE and I knew of that browser's fondness for SVG animation, but the timing effects were just too bloody messy. Development time per transition was about four times as long, and I was interested in a showcase of possibilities (from which to crowdsource other contributions). I'll think about scripting it all later, or borrowing FakeSMILe to see how far it might take me, in hopes of reaching IE. I need to use some script anyhow, I suspect to incrementally pre-cache some of the images (or ultimately web pages and video-clips)

Anyhow, I knew that work was underway on CSS animation, but the last time I bopped in to look at things in extant browsers (two years ago?) the cross-browser support seemed negligible. I was persuaded that now might be the time to look deeper. I was encouraged to see that IE now supports some declarative animation.

So, if I am correct in reading what you, Dirk and Tab have written, it appears that my real questions (using more accurate terminology) should have been:
1. Will something like href, while not a presentation attribute and hence not stylable in CSS, still be animatable using CSS?
2. What might the syntax for doing such be?
3. Is that all spelled out in http://dev.w3.org/fxtf/web-animations/ ? If so I will read more carefully.
4. When might we expect such things to actually work in browsers (particularly IE where it most matters)? Just an aside: HTML5 with its apparent embrace of the philosophy of never-converging toward a completed spec, seems to have created quite a plethora of different experimental technologies being embraced in different browsers. I rather preferred having finite specs, like SVG 1.1 where it was easier to tell which browsers were compliant and which weren't.

The goal you mention of reducing "the pressure to make things which are clearly not suitable as properties, into properties just so they can be animated" seems like a good one, and I am pleased to see all the hard thought that has been put into these issues!


Cheers
David

Received on Saturday, 22 March 2014 14:26:12 UTC