[svgwg] `SVGAngle.animVal.unitType`  during animation between different units is unspecified (#1146)

viralipurbey has just created a new issue for https://github.com/w3c/svgwg:

== `SVGAngle.animVal.unitType`  during animation between different units is unspecified ==
When animating an angle between two different units, e.g.  orient   from="0deg" to="200grad" , the spec doesn't say what  `animVal.unitType`  should report during the animation.

```
 <animate attributeName="orient" from="0deg" to="200grad" dur="4s"/>
```

The value is well defined and continuous; only the reported unit is ambiguous. The WPT  svgangle-animation-unitType.html(https://wpt.fyi/results/svg/animations/svgangle-animation-unitType.html?label=master&label=experimental&aligned&q=svgangle-animation-unitType) expects it to switch from  `deg`  to  `grad`  past the midpoint,  but per wpt.fyi no engine passes it.

Could we define this? My preference is to always report the canonical unit ( deg ), consistent with CSS  `<angle>`  interpolation (canonical-unit) but the main ask is just that some interoperable behavior be specified.

https://www.w3.org/TR/css-values-4/#canonical-unit

Please view or discuss this issue at https://github.com/w3c/svgwg/issues/1146 using your GitHub account


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Received on Thursday, 2 July 2026 04:03:00 UTC