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Re: [css3-transitions] Back-tracking transition-timing-function

From: Tab Atkins Jr. <jackalmage@gmail.com>
Date: Thu, 22 Apr 2010 17:29:40 -0700
Message-ID: <i2idd0fbad1004221729la27d24daw1c4a7c83a82d6e58@mail.gmail.com>
To: Alex Meiburg <timeroot.alex@gmail.com>
Cc: www-style@w3.org
On Thu, Apr 22, 2010 at 5:23 PM, Alex Meiburg <timeroot.alex@gmail.com> wrote:
> In the case that the points P1 and P2 were too over extended from (0,0) and
> (1,1), respectively, the curve they generate could end up back-tracking to
> some extent. In the event of some bad code that does this, how should the
> user agent handle it? Should it simply skip from the lower branch of the
> function to the higher branch? Should it readjust the values of P1 and P2 so
> that the back-tracking is removed? Should it ignore the transition entirely?
>
> In addition, should coordinates of P1 and P2 outside the [0-1] range be
> allowed? There are some well formed cubic bezier curves with control points
> outside the square that stay inside the square continuously.

The cubic-bezier() function only allows values in [0,1].  Any values
outside of that range make the declaration invalid.

Within that range, you're guaranteed that the curve will be
monotonically increasing (or maybe just non-decreasing?), and thus is
invertible.

~TJ
Received on Friday, 23 April 2010 00:30:32 GMT

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