[svgwg] Status of SVG_MARKER_ORIENT_AUTO_START_REVERSE, missing IDL in SVG2? (#993)

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

== Status of SVG_MARKER_ORIENT_AUTO_START_REVERSE, missing IDL in SVG2? ==
# Context

On `SVG_MARKER_ORIENT_AUTO_START_REVERSE`

In SVG 1.1, the [`orient`](https://www.w3.org/TR/SVG11/painting.html#OrientAttribute) attribute is defined with the values <code>auto | &lt;angle></code>

The SVG 1.1 [idl](https://www.w3.org/TR/SVG11/painting.html#InterfaceSVGMarkerElement) for `SVGMarkerElement` defines 

```
 // Marker Orientation Types
  const unsigned short SVG_MARKER_ORIENT_UNKNOWN = 0;
  const unsigned short SVG_MARKER_ORIENT_AUTO = 1;
  const unsigned short SVG_MARKER_ORIENT_ANGLE = 2;
```

In SVG2, the [orient](https://svgwg.org/svg2-draft/painting.html#OrientAttribute) attribute has for values <code>auto | auto-start-reverse | &lt;angle> | &lt;number>.

The SVG 2 [idl](https://svgwg.org/svg2-draft/painting.html#InterfaceSVGMarkerElement)  for `SVGMarkerElement` defines 

```
  // Marker Orientation Types
  const unsigned short SVG_MARKER_ORIENT_UNKNOWN = 0;
  const unsigned short SVG_MARKER_ORIENT_AUTO = 1;
  const unsigned short SVG_MARKER_ORIENT_ANGLE = 2;
```

There is a WPT test for "Animate SVGMarkerElement orientAttr from auto to auto-start-reverse"
https://wpt.fyi/results/svg/animations/animate-marker-orient-from-auto-to-auto-start-reverse.html

which has `assert_equals(marker.orientType.animVal, SVGMarkerElement.SVG_MARKER_ORIENT_AUTO_START_REVERSE);`
https://github.com/web-platform-tests/wpt/blob/05f9b8724c/svg/animations/animate-marker-orient-from-auto-to-auto-start-reverse.html#L79

* Firefox: PASS
* Chrome: FAIL
* Safari: FAIL


And indeed Firefox has its webidl in accordance with the test. 
https://searchfox.org/mozilla-central/rev/ce0d41b6033e2a104904327a43edf730245f5241/dom/webidl/SVGMarkerElement.webidl#21-25
```
// Marker Orientation Types
const unsigned short SVG_MARKER_ORIENT_UNKNOWN = 0;
const unsigned short SVG_MARKER_ORIENT_AUTO = 1;
const unsigned short SVG_MARKER_ORIENT_ANGLE = 2;
const unsigned short SVG_MARKER_ORIENT_AUTO_START_REVERSE = 3;
```

and implemented in https://searchfox.org/mozilla-central/search?q=SVG_MARKER_ORIENT_AUTO_START_REVERSE&path=&case=false&regexp=false

# Question

Is the SVG 2 spec is missing the correct IDL? 
and we need to amend the spec. 

Or was there a decision to remove it from the spec (I do not see that from the previous issues).


Please view or discuss this issue at https://github.com/w3c/svgwg/issues/993 using your GitHub account


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Received on Friday, 15 August 2025 04:03:55 UTC