Re: [svgwg] The interpolation of large_arc_flag/sweep_flag of Elliptical Arc in SVG Path

The SVG Working Group just discussed `The interpolation of large_arc_flag`, and agreed to the following:

* `RESOLUTION: Flipping boolean and integers half way for path interpolation`

<details><summary>The full IRC log of that discussion</summary>
&lt;krit> topic: The interpolation of large_arc_flag<br>
&lt;krit> GitHub: https://github.com/w3c/svgwg/issues/543<br>
&lt;krit> krit: thought SMIL animates it half way already? What is the difference?<br>
&lt;krit> chris: it affectively is a boolean that gets flipped.<br>
&lt;krit> krit: doesn't the flip at 0.5 happen already?<br>
&lt;krit> AmeliaBR: no, SVG SMIL defines that integers get interpolated as number and everything not 1 gets set to 0.<br>
&lt;AmeliaBR> s/not 1 gets set to 0/not 0 gets set to 1/<br>
&lt;krit> AmeliaBR: would a change here affect that all SMIL animated integers would animate the half-way flip?<br>
&lt;krit> krit: this is likely for WebKit and Blink.<br>
&lt;krit> krit: Many SVG 1,1 tests may fail if implementations change for all SMIL integer animations.<br>
&lt;krit> chris: but likely not the tests on WebPlatform.<br>
&lt;krit> krit: probably not.<br>
&lt;krit> chris: we have the option to change the test then or remove it as obsolete.<br>
&lt;krit> krit: I am nor sure if implementations would care about the change.<br>
&lt;krit> AmeliaBR: we could allow to use both ways recommending the half-way flip.<br>
&lt;krit> Tavmjong: did anyone test it yet.<br>
&lt;krit> krit: I see that Brian is participating in the issue as well. Is that something that the web animation spec can do it.<br>
&lt;krit> AmeliaBR: There is no other spec that defines how to interpolate path.<br>
&lt;krit> chris: I think the motion spec might define it.<br>
&lt;krit> chris: ppl using path Interpolation probably don't use elliptic path segments.<br>
&lt;krit> AmeliaBR: likely but we need to define it still.<br>
&lt;krit> krit: any preferences?<br>
&lt;krit> chris: My preference is flipping at 0.5.<br>
&lt;krit> Tavmjong: me too.<br>
&lt;krit> AmeliaBR: most sensible.<br>
&lt;krit> AmeliaBR: Likely no serious web compatibility issue.<br>
&lt;krit> AmeliaBR: but there should be a note that the behavior changed,<br>
&lt;krit> AmeliaBR: Motion path is deferring to SVG 1.1<br>
&lt;krit> krit: do we still have the animation chapter? Think we removed it.<br>
&lt;krit> AmeliaBR: defined in the path chapter. That needs to be written as an abstract data type instead of a certain property.<br>
&lt;krit> AmeliaBR: change needs to happen in https://svgwg.org/svg2-draft/paths.html#TheDProperty 7th paragraph<br>
&lt;krit> AmeliaBR: We also need to add interpolation for the path() function.<br>
&lt;krit> chris: I can take that and do the edit.<br>
&lt;krit> AmeliaBR: Check with Eric.<br>
&lt;krit> chris: yes will add ppl to the PR reviewer list.<br>
&lt;krit> RESOLUTION: Flipping boolean and integers half way for path interpolation<br>
</details>


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Received on Monday, 17 September 2018 20:01:07 UTC