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Proposal for addressing animation questions [Was Re: Animation]

From: Ian Jacobs <ij@w3.org>
Date: Thu, 08 Mar 2001 13:34:25 -0500
Message-ID: <3AA7D0B1.365AC9C@w3.org>
To: Charles McCathieNevile <charles@w3.org>
CC: WAI UA group <w3c-wai-ua@w3.org>, WAI Cross-group list <wai-xtech@w3.org>
Charles McCathieNevile wrote:
> 
> I took an action item to define animation for the UA wroking group. Here is
> my first cut:
> 
> Animation:
> (Need to check the SVG spec to make sure we are saying the same things, but
> roughly:
> An animation is anything that changes with time according to some rule
> specified by the author. 

This would include automatic page refreshes (this is common
for animated effects, I believe) and multimedia presentations. 

If you allow manual refresh, the W3C home page is an animation
that changes very slowly over time.

> For example, an image which changes to give the
> illusion of motion, or a video, or text that scrolls in place are all
> examples of animations. Animations may be single framed objects, such as
> videos or animated images, or may be effects that rely on several different
> page elements - for example regions of a presentation moving around the page
> dynamically.

This is from the "Webopedia" definition [1] (which I don't really like,
but for this part):

  "A simulation of movement created by displaying a series of
   pictures, or frames."

I like the focus on the simulation of movement.

---------
PROPOSAL
---------

What about something like this:

<DFN>
  Animation: a visual effect of simulated movement. Animation
  techniques include:
 
    * displaying a series of snapshots in a fixed graphical
      region (e.g., as is done for video and animated images).
      The series of snapshots may be part of a single resource
      (e.g., an animated GIF image) or individual resources
      (e.g., a series of images downloaded continuously by
      the user agent).
    * scrolling text (e.g., achieved through markup or
      style sheets).
    * displacing graphical objects around the viewport
      (e.g., a picture of a ball that is moved around the viewport
      giving the impression that it is bouncing off of the
      viewport edges).
</DFN>

I remind Charles that part of the action item from the
face-to-face meeting was to explain why checkpoint 3.2
should say "video or animated images" and 4.4 should
say "video and animations". If video and animated images
are subclasses of animation, then 4.4 could just refer
to animations (it doesn't need to mention video, or if
it mentions video, I think it should also mention animated
images explicitly as in 3.2).

My question on this topic was initially this:
we have three checkpoints that refer to animated things:

 - 3.2: Turn off video and animated images
 - 3.3: Turn off animated text
 - 4.4: Slow video and animations

I think that we should not change any of the requirements,
but instead:

a) Define animation to be a superclass that includes video,
   animated images, and other motion within the viewport.

b) Change 4.4 to read "animations (including video and animated
   images)"

c) For 4.4, we include the SMIL 2.0 techniques related to the
   'speed' attribute (currently implemented in IE 5.5 for Windows).

 - Ian


  
  



[1] http://webopedia.internet.com/TERM/a/animation.html


-- 
Ian Jacobs (jacobs@w3.org)   http://www.w3.org/People/Jacobs
Tel:                         +1 831 457-2842
Cell:                        +1 917 450-8783
Received on Thursday, 8 March 2001 13:34:29 GMT

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