[geometry-1] propose adding DOMPoint as an argument for DOMMatrix that accepts vectors.

[trusktr]

For example we can currently do this:

const mat = new DOMMatrix()

mat.translateSelf(10, 20, 30)

and this:

const mat = new DOMMatrix()
const movement = new DOMPoint(10, 20, 30) // This can be used like a "Vector3" or "vec3" in other libraries

mat.translateSelf(movement.x, movement.y, movement.z)

To simplify things, especially once we add more methods that can help people do more things with matrices and points (i.e. vectors), it would be nice to be able to simply pass points around where they can be used:

const mat = new DOMMatrix()
const movement = new DOMPoint(10, 20, 30) // This can be used like a "Vector3" or "vec3" in other libraries

mat.translateSelf(movement) // new option: pass a DOMPoint directly.

If the first parameter to translateSelf can accept a DOMPointInit, then it can accept a POJO as well as an actual DOMPoint instance to match with patterns of other methods (for example those that accept DOMMatrixInit), and we would similarly upddate for other methods that accept individual vector values to also accept DOMPointInit values.