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Re: Request for Comments: Proposal for Touch-Based Animation Scrubbing

From: Tab Atkins Jr. <jackalmage@gmail.com>
Date: Thu, 29 Nov 2012 09:52:38 -0800
Message-ID: <CAAWBYDDnntztc7T+48vFCxyrzJJCQm+5G3go_F-oWL4=f=NZWw@mail.gmail.com>
To: Florian Rivoal <florian@rivoal.net>
Cc: www-style list <www-style@w3.org>
On Thu, Nov 29, 2012 at 1:12 AM, Florian Rivoal <florian@rivoal.net> wrote:
> On Thu, 29 Nov 2012 02:36:33 +0100, Tab Atkins Jr. <jackalmage@gmail.com>
> wrote:
>> Thoughts?  Does anyone I haven't spoken to about this think it's
>> crazy?  Would you like to see working examples (done with a JS shim,
>> of course) of the functionality?  We haven't done any impl work yet,
>> but implementing this or something that solves the same problem is a
>> priority for the Chrome team in the next few months, so feedback
>> sooner rather than later would be great.
>
>
> There's one thing that I think would be useful, that seems to be missing.
>
> Say you're pulling a tray to open it. You might want to have a threshold
> point, say around 50%. When you releasse before the threshold, the tray
> falls back to 0, but if you release after it, it goes to the end. Notches
> aren't quite the same, as you need to get close by before they snap. You
> might be able to do it with accelerating momentum curves, but it sounds like
> a very roundabout way to go after it.

Nope, that's already there.  Set notches at 0% and 50%, with "force"
mode.  When you let go, it'll drift to the nearest notch
automatically.

For notches that you need to be "near" to activate, use the "bias"
mode, which auto-adjusts momentum curves.

Better control over this might be useful, of course - a mode where it
force-drifts, but only when you're near, might be useful.

> Maybe another way would be to address the usecase more directly than with
> ranges mapping to other named animations, and instead define gravity
> centers, with affected ranges. when you're scrubbing, ignore them, when you
> release, if you're in an affected range, fall towards the center.

Yes, I thought of this.  Right now the behavior is just to find the
nearest notch, which means that the space between two notches is
implicitly divided in half, with each half owned by a notch.  This
isn't necessarily what you want - I can think of drawer-like UIs where
you want the drawer to close itself (0% notch) when it's <20% through
its curve, but expand out to fully open (100% notch) otherwise.  This
would require the ability to explicitly assign ranges around a notch.

I haven't done anything with it yet, though.

~TJ
Received on Thursday, 29 November 2012 17:53:27 GMT

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