`SVGTransform.matrix` returns `SVGMatrix` in all browsers

[caugner]

In SVG 1.1, SVGTransform.matrix returns SVGMatrix. In SVG 2, it returns DOMMatrix.

In all browsers, SVGTransform.matrix returns SVGMatrix.

It was decided to revert this change, but the issue was closed without reverting this change.

[karlcow]

@caugner Do you mean to revert in the spec prose?

Scalable Vector Graphics (SVG) 2
W3C Editor’s Draft 14 September 2025

I reverted here
karlcow@921dba3

I may have missed sections? I will check today.
https://svgwg.org/svg2-draft/

[caugner]

@karlcow The SVGTransform IDL still has DOMMatrix for matrix (and DOMMatrix2DInit for setMatrix()):

svgwg/master/coords.html

Lines 3206 to 3209 in c82ab6a

	[<a>SameObject</a>] readonly attribute <a>DOMMatrix</a> <a href="coords.html#__svg__SVGTransform__matrix">matrix</a>;
	readonly attribute float <a href="coords.html#__svg__SVGTransform__angle">angle</a>;
	undefined <a href="coords.html#__svg__SVGTransform__setMatrix">setMatrix</a>(optional <a>DOMMatrix2DInit</a> matrix = {});

[Ahmad-S792]

https://searchfox.org/firefox-main/source/dom/webidl/SVGTransform.webidl#31

^ Firefox has DOMMatrix2DInit

[caugner]

https://searchfox.org/firefox-main/source/dom/webidl/SVGTransform.webidl#31

^ Firefox has DOMMatrix2DInit

Good catch:

Engine	{} matrix	setMatrix({} matrix)
Chromium	SVGMatrix	SVGMatrix
Gecko	SVGMatrix	optional DOMMatrix2DInit
WebKit	SVGMatrix	optional DOMMatrix2DInit

[karlcow]

The specs:

SVG 1.1
W3C Recommendation 16 August 2011
https://www.w3.org/TR/2011/REC-SVG11-20110816/

  readonly attribute unsigned short type;
  readonly attribute SVGMatrix matrix;
  readonly attribute float angle;

  void setMatrix(in SVGMatrix matrix) raises(DOMException);

SVG2
https://svgwg.org/svg2-draft/single-page.html#coords-InterfaceSVGTransform
W3C Editor’s Draft 14 September 2025

  readonly attribute unsigned short type;
  [SameObject] readonly attribute DOMMatrix matrix;
  readonly attribute float angle;

  undefined setMatrix(optional DOMMatrix2DInit matrix = {});

Chromium
https://github.com/chromium/chromium/blob/37969c6446f6082a13e66356cf08539b269074af/third_party/blink/renderer/core/svg/svg_transform.idl#L37-L40June 15, 2019

    [ImplementedAs=transformType] readonly attribute unsigned short type;
    // TODO(foolip): SVGMatrix should be DOMMatrix.
    readonly attribute SVGMatrix matrix;
    readonly attribute float angle;


    // TODO(foolip): SVGMatrix should be DOMMatrixReadOnly.
    [RaisesException] void setMatrix(SVGMatrix matrix);

Gecko
https://github.com/mozilla-firefox/firefox/blob/94583492da555d7f1c229b4d43c5e74e415a72d1/dom/webidl/SVGTransform.webidl#L25-L28
December 28, 2022

  readonly attribute unsigned short type;
  [BinaryName="getMatrix"]
  readonly attribute SVGMatrix matrix;
  readonly attribute float angle;


  [Throws]
  undefined setMatrix(optional DOMMatrix2DInit matrix = {});

WebKit
https://github.com/WebKit/WebKit/blob/7c8968c2ec20b0c7e94513704ce4773ae6c0e134/Source/WebCore/svg/SVGTransform.idl#L38-L41

    readonly attribute unsigned short type;
    [SameObject] readonly attribute SVGMatrix matrix;
    readonly attribute float angle;


    undefined setMatrix(optional DOMMatrix2DInit matrix = {});

OK I understand your table now.

Resolutions ( Oct 22, 2019):

• RESOLVED: Revert decision to make SVG* geometry interfaces aliases of the DOM* geometry interfaces (pending CSS WG approval)
• RESOLVED: Change the SVG spec to use the SVG* geometry interfaces instead of DOM* interfaces
• RESOLVED: Keep the usage of DOM*Init types in the SVG spec
• RESOLVED: Ask CSS WG to approve separating out most of the geometry interfaces into mixins we can reference in SVG interface definitions.

The discussions refer to the DOM* geometry interfaces which I believe are in
https://www.w3.org/TR/2014/WD-geometry-1-20140522/
Geometry Interfaces Module Level 1
W3C First Public Working Draft, 22 May 2014

which became:

https://drafts.csswg.org/geometry/
Geometry Interfaces Module Level 1
W3C Candidate Recommendation Draft, 12 December 2025

There is a mention of SVG into it.
10.2. SVG

Earlier revisions of SVG defined SVGPoint, SVGRect, SVGMatrix, which are defined in this specifications as aliases to DOMPoint, DOMRect, DOMMatrix, respectively. [SVG11]