[svgwg] [circle][ellipse] SVG 2 silent on negative values for cx/cy (#1145)

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

== [circle][ellipse] SVG 2 silent on negative values for cx/cy ==
SVG 2 silent on negative cx/cy semantics; 

3-engine convergent on accepting (asymmetry vs rx/ry which forbid)

geometry.html: CX/CY propdef tables declare value space `<length-percentage>` without saying anything about negative values. 
In contrast, geometry.html: RX/RY explicitly state "A negative value for rx is invalid and must be ignored" (and equivalent for ry).

Tests already exist:

* svg/geometry/parsing/cx-valid.svg: test_valid_value("cx", "-1px")
* svg/geometry/parsing/cy-valid.svg: test_valid_value("cy", "-1px")
* svg/geometry/parsing/rx-invalid.svg: test_invalid_value("rx", "-1px")
* svg/geometry/parsing/ry-invalid.svg: test_invalid_value("ry", "-1px")

There is still a bit of lack of coverage with regards to it

**Proposal**:

1. adds WPT
2. adds the mention that negative values are forbidden like for rx, ry. 


Please view or discuss this issue at https://github.com/w3c/svgwg/issues/1145 using your GitHub account


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Received on Wednesday, 1 July 2026 07:26:09 UTC