[whatwg] Singular CTM and currentTransform

Rik Cabanier cabanier at gmail.com
Tue Mar 25 12:46:47 PDT 2014

On Tue, Mar 25, 2014 at 12:35 PM, Justin Novosad <junov at google.com> wrote:

> On Tue, Mar 25, 2014 at 3:15 PM, Rik Cabanier <cabanier at gmail.com> wrote:
>> I agree. That issue has the same root problem as currentTransform.
>> It would be nice to get closure.
>> Justin, you hinted that you would be willing to follow the spec which
>> would make you match Firefox and IE.
>> Are still planning on doing that?
> I'm in a holding pattern. I prepared a code change to that effect, but
> then there was talk of changing the spec to skip path primitives when the
> CTM is not invertible, which I think is a good idea. It would avoid a lot
> of needless hoop jumping on the implementation side for supporting weird
> edge cases that have little practical usefulness.
> Right now, there is no browser interoperability when using non-invertible
> CTMs, and the web has been in this inconsistent state for a long time.  The
> fact that this issue has never escalated (AFAIK) is a strong hint that no
> one out there really cares about this use case, so we should probably just
> go for simplicity. Maklng path primitives and draw calls no-ops when the
> CTM is non-invertible is simple to spec, implement, test, and understand
> for developers.

Great to hear!
I volunteer to update the Firefox implementation if we can get consensus.
(see https://bugzilla.mozilla.org/show_bug.cgi?id=931587)

> Note that Firefox is still non-compliant if there's a non-invertible
>> matrix during filling/stroking/clipping
>>> > PS: This is one reason I prefer a getter over an attribute because the
>>> > getter does not return a mutable (live) SVGMatrix. But even than the
>>> > problem above is not fully solved of course.

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