Steps to reproduce:

Original proposal: https://github.com/fserb/canvas2D/blob/master/spec/roundrect.md

Spec: https://html.spec.whatwg.org/multipage/canvas.html#dom-context-2d-roundrect

Recent spec change: https://github.com/whatwg/html/pull/7621#event-6093663928

Do you think we need to prioritize this?

If it is in the spec and someone wants to go ahead and implement it, I don't see why not, but unless it's a webcompat issue I don't know that it's a distinct priority yet?

Can I work on it?

Can I work on this?

(In reply to Deebash D from comment #4)

Can I work on this?

Anyone is welcome to contribute to Mozilla, if they feel they're up to it. If it is your first time contributing code to Mozilla, reviewing https://firefox-source-docs.mozilla.org/setup/contributing_code.html is probably of use.

I implemented parts of this, but I probably won't be able to finish this without some help.

• Bug 1814235 means the current WebIDL as specified doesn't work
• I don't understand how to support mDSPathBuilder, which seems to require transforming everything?
• The CanvasPath implementation is missing, but hopefully we can just re-use most of the CanvasRenderingContext2D implementation for that.

Hi Andrew! Maybe you could give me some hints? See comment 7, especially point two and three.

(In reply to Tom S [:evilpie] from comment #7)

• Bug 1814235 means the current WebIDL as specified doesn't work

I landed a fix for this, it should work now. Let me know if you run into any other issues!

Thank you Peter! We are now down to only two failures in the WPT html/canvas/element/path-objects/ test suite, those might be related to the scaling that is supposed to be done in Step 11? The two other questions, particular about mDSPathBuilder remain.

/html/canvas/element/path-objects/2d.path.roundrect.radius.intersecting.1.html
  FAIL Check that roundRects with intersecting corner arcs are rendered correctly. - assert_equals: Red channel of the pixel at (2, 25) expected 0 but got 63
/html/canvas/element/path-objects/2d.path.roundrect.radius.intersecting.2.html
  FAIL Check that roundRects with intersecting corner arcs are rendered correctly. - assert_equals: Red channel of the pixel at (1, 1) expected 255 but got 0

Thanks everyone for your hints, we are only with those two failures in comment 10 left now.

https://hg.mozilla.org/mozilla-central/rev/154b792529c2

FF112 MDN docs work for this can be tracked in https://github.com/mdn/content/issues/25359.
Essentially this is just an MDN release note and browser compatibility data update, since this API is documented.