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Re: [csswg-drafts] [css-easing-2] Complex easing/timing functions (#229)

From: Sebastian Zartner via GitHub <sysbot+gh@w3.org>
Date: Sat, 27 Apr 2019 22:25:26 +0000
To: public-css-archive@w3.org
Message-ID: <issue_comment.created-487324378-1556403925-sysbot+gh@w3.org>
> ... it requires extra work to calculate a y-value (interpolated value) at a given x value (time progress or position).

Can you please elaborate on that? I don't see why that's work than multiple Beziérs.

> And there is no guarantee that you'd get a single y value for any x value.

Right, same issue for Beziérs.

I see two solutions for this problem:

1. Invalidate those paths or Beziérs as [you mentioned earlier](https://github.com/w3c/csswg-drafts/issues/229#issuecomment-484310242).
2. Clamp the x coordinate so that the path always increases in x direction. This possibly manipulates the path but makes all paths or Beziérs valid.

Visualisation for the latter:

Input path:
<img width="600" alt="path" src="https://user-images.githubusercontent.com/958943/56855697-d778e980-694b-11e9-9074-60a7016bbc51.png">

Normalized path:
<img width="600" alt="clamped path" src="https://user-images.githubusercontent.com/958943/56855695-d778e980-694b-11e9-9c38-cac63dc80af6.png">

Sebastian

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Received on Saturday, 27 April 2019 22:25:28 UTC

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