- From: Chris Marrin <cmarrin@apple.com>
- Date: Mon, 05 Apr 2010 10:07:15 -0700
- To: "www-style@w3.org list" <www-style@w3.org>
On Apr 4, 2010, at 4:37 PM, Perry Smith wrote: > > On Apr 4, 2010, at 3:12 PM, Tab Atkins Jr. wrote: > >> On Sun, Apr 4, 2010 at 11:23 AM, Perry Smith <pedzsan@gmail.com> wrote: >>> Perhaps instead of calling them 'states' or 'state changes', call them >>> 'events'. I'm new to this list so I don't understand Håkon's statement, >>> "We'd like to do this without adding an event model to CSS." It may be that >>> my way of thinking opens a can of worms that has already been discussed. >>> >>> First, it solves Simon's concerns because the event would not happen when a >>> class is added or removed. >> >> It doesn't solve the concerns so much as eliminate them, because it >> makes transitions much weaker. A lot of transition usage will be >> based on :hover, :focus, etc., but a lot of it *won't* be. There are >> tons of places in code that I've written where I'd like to animate >> some property change triggered by me swapping classes. >> >> Simon points out, correctly, that trying to hack an event model that >> responds to arbitrary selector matching changes would turn super-crazy >> very quickly. Both in terms of simple mechanics, and in terms of what >> authors have to keep track of (the 'combinatorial explosion' he >> mentions). > > I clearly don't understand the objective. > > If the user already is using javascript to change classes, then he can define the animations like script.aculo.us and others do. > > I thought the desire was to have something so, lets call them "graphic artists", can use without knowing or mucking with JS. Someone used the term "declarative". I took that to mean something I can declare in CSS alone. There is much more than just the convenience of a declarative form here. One of the biggest motivators for Transitions and Animations was to create a system that could perform animations in hardware. On embedded platforms, running Javascript timers and rerendering the entire page for each step quickly becomes expensive enough that framerates become unacceptably slow. ----- ~Chris cmarrin@apple.com
Received on Monday, 5 April 2010 17:07:48 UTC