- From: Shane Stephens <shans@google.com>
- Date: Thu, 17 Apr 2014 08:30:35 +1000
- To: Domenic Denicola <domenic@domenicdenicola.com>
- Cc: Douglas Stockwell <dstockwell@google.com>, "public-fx@w3.org" <public-fx@w3.org>, "bbirtles@mozilla.com" <bbirtles@mozilla.com>, Rik Cabanier <cabanier@gmail.com>, Paul Irish <paulirish@google.com>
- Message-ID: <CAGTfzwSTN4uyjbKE3rgm7JzWEdxFm3UJk+BHbB3dVqO5D_PCmw@mail.gmail.com>
On Thu, Apr 17, 2014 at 8:21 AM, Domenic Denicola < domenic@domenicdenicola.com> wrote: > Regardless of spec examples, all of the real-world CSS transition and > animation code I've seen uses the ms unit, not the s one. I don't think CSS > provides any guidance here. > The first three sites I found transitions on use seconds: google.com uses 0.1s, 0.5s (not 100ms, 500ms). twitter.com uses 0.3s (not 300ms) www.smh.com.au uses 0.4s, 0.1s (not 400ms, 100ms) Literally the first 3 transitions tutorials I found use seconds: https://developer.mozilla.org/en-US/docs/Web/Guide/CSS/Using_CSS_transitions http://css3.bradshawenterprises.com/transitions/ http://docs.webplatform.org/wiki/tutorials/css_transitions Do you have counter-examples? Cheers, -Shane > ------------------------------ > From: Shane Stephens <shans@google.com> > Sent: 4/16/2014 6:04 PM > To: Douglas Stockwell <dstockwell@google.com>; public-fx@w3.org; > bbirtles@mozilla.com; Rik Cabanier <cabanier@gmail.com>; Domenic Denicola<domenic@domenicdenicola.com>; > Paul Irish <paulirish@google.com> > Subject: Units of time in Web Animations [was: Intent to Ship: > Element.animate] > > +public-fx > > We welcome discussion on this topic, but I encourage everybody to > consider the full range of data before making a case based off a single > data point. > > Existing APIs and tools > ------------------------------- > (1) Although units are specified, CSS Animations, CSS Transitions and SVG > Animations all strongly default to seconds units (not a single example in > any specification presents an animation with 'ms'). More than 50% of page > views involve one of these APIs, which strongly suggests that the default > animation unit on the web today is seconds, not milliseconds. > (2) The JavaScript exposures of CSS Animations, CSS Transitions and SVG > Animations (e.g. events, ElementTimeControl) all treat inputs and outputs > as time in seconds. > (3) Native media APIs (Web Audio, Media Elements) use seconds > (4) some third-party animations libraries (e.g. Core Animations, WPF > [kinda], GSAP, animo) use seconds > (5) industry tools like Adobe AfterEffects tend to report time values in > seconds > > We need to balance this against: > (1) Native platform APIs dealing with time (e.g. performance.now) return > milliseconds > (2) requestAnimationFrame reports time in milliseconds > (3) some other third-party animations libraries (e.g. jQuery, d3, tween, > collie, minified, rekapi) use milliseconds. Note that I was unable to find > examples of animation libraries outside of the realm of JavaScript that use > milliseconds. > > Interoperability > -------------------- > Our mandate is to unify CSS and SVG. I think this induces a pretty clear > requirement to keep using the unit of time measurement common to these > technologies, rather than changing it. > > More than 50% of all page views (source: > http://www.chromestatus.com/metrics/css/popularity) involve CSS > Animations or Transitions. I strongly doubt that the total usage count of > all third-party animations libraries added together comes close to this. > Again, a strong indicator that the most common animation time unit out > there is seconds, not milliseconds. > > Outside of the web, the industry overwhelmingly prefers seconds, from > what I can tell. > > Balancing this, most (but not all) JavaScript that deals with time does > so in milliseconds (exceptions: events from CSS and SVG, some animation > libraries, any code dealing with media or audio). > > "Correctness" > ------------------- > In the absence of pre-existing libraries, tools, or APIs, what would we > pick? > > I would argue that it is uncommon if not rare to require animations on a > millisecond time scale, but that it is extremely common to require > animations on a second time scale. Even the range of ~0.1s - 1s is quite > naturally expressed as a fraction of a second. > > Humans have no intuitive understanding of the length of a millisecond, > other than as a tiny portion of the much more natural unit of seconds. > > Cheers, > -Shane >
Received on Wednesday, 16 April 2014 22:31:04 UTC