[geometry] point.matrixTransformSelf

[jakearchibald]

https://drafts.fxtf.org/geometry/#DOMPoint

Matrix objects have *self methods that transforms the current matrix rather than creating a new object. If this is a pattern to avoid garbage in hot code, then point.matrixTransformSelf seems missing.

point.matrixTransformSelf would behave like point.matrixTransform, except the context object would be modified, rather than creating a new DOMPoint.

[dirkschulze]

@jakearchibald Since DOMPoint doesn't have any *self methods like DOMMatrix. I don't think we even thought about adding *self to DOMPoint to be honest. Do you think that this can move to level 2 of the spec?

[jakearchibald]

I'll leave it to you to decide. Btw I'm writing as a web developer, not an implementor, I can't really speak for implementation interest on this.

In my use case I'm looping through some ImageData data, and creating some new ImageData as the result of a transform, so I'm calling point.matrixTransform for each pixel.

[dirkschulze]

Oh I see. Yeah, the *self functions were introduced to chain the transformations:

matrix.translateSelf(...).scaleSelf(...).rotateSelf(...);

So we probably didn't thought about other use cases at the time. Also, creating new instances of matrix with 16 slots (and another for is2D) is heavier than transformations on DOMPoint. I still see value on *Self in general though.

[chrishtr]

I agree, this should be added.