- From: Dr. Olaf Hoffmann <Dr.O.Hoffmann@gmx.de>
- Date: Fri, 8 Apr 2011 10:22:14 +0100
- To: www-svg@w3.org
Brian Birtles: ... > > > Well, I you have a look for example into the CSS transitions draft, > > this might give an idea. > > It is not perfect either, but indicates, that several people assume, > > that something like this has use cases. > > Please provide specific reference. I can't see any case in CSS > transitions where the transition is adding to a value in change, stops > mid-interval, and then maintains that intermediate value masking > underlying changes. > As far as I understand this, this is always implicated, the transitions start always from the current state. Each time a new transition starts, it starts with the current state. CSS animations and transitions currently have no additive behaviour - concerning this, a precise timing model or interactivity, the drafts are still pretty rudimentary. Obviously to-animations are slightly more elegant due to the precisely defined formula - I think, transitions at least don't jump, to-animations are really smooth. A common use case, of at least where I expect it should work this way, what is currently not possible in SVG without to-animations, is a combination with interactivity causing a smooth change when events occur. For example you have a button, with mouseover it changes to one color, with mouseout to another, with mouseup and mousedown to other colors again. If the user moves the mouse fast or the same animation has to be restarted due to an event, with your idea (or what is currently typically implemented) there is always a sudden change, a jump corrupting the intended effect. This can be avoided, when the frozen state conserves the current value. It is not completely trivial to create such buttons, but at least possible with correct implemented to-animations. Unfortunately the current CSS transition draft has no events like mouse*, therefore it is of limited use for this purpose either, therefore it would be fine to have at least to-animations properly working for this purpose in SVG. Parts of the bugs can be covered with restart="whenNotActive", but this is a slightly different effect, because it covers the problem effectively by ignoring too fast user interactivity, example here (mouseover and mouseout on the image): http://hoffmann.bplaced.net/svgtext/image01.svg The following is the originally intended document, something like this could be pretty common, if to-animations would work in current viewers: http://hoffmann.bplaced.net/svgtext/image03.svg Correctly implemented, the changes of the size of the image would be always smooth with mouseover and mouseout without ignoring interactivity from the user. Olaf
Received on Friday, 8 April 2011 09:22:44 UTC