[whatwg] [Canvas] Behavior on non-invertable CTM

[Rik Cabanier]

On Mon, Mar 17, 2014 at 1:47 PM, Justin Novosad <junov at google.com> wrote:

>
>
>>
>>
>>> I have a fix in flight that fixes that problem in Blink by storing the
>>> current path in transformed coordinates instead. I've had the fix on the
>>> back burner pending the outcome of this thread.
>>>
>>
>> That seems like an expensive solution because this causes the coordinates
>> to be transformed twice.
>> Why not store the matrix that was applied to the path coordinates and use
>> that to undo the transformation?
>>
>
Dirk and I looked over the WebKit code and it's actually already doing this.


> If we decide that the right thing is to do nothing when when the CTM is
> non-invertible, then sure, we can just do that. The idea of storing the
> current path in transformed coordinates was to also support drawing with a
> non-invertible CTM, like Firefox does, which is what Ian stated was the
> correct behavior earlier in this thread.
>

yeah, but then FF bails at draw time anyway.
IMO no author relies on behavior when there's a non-invertible matrix so we
should just implement the simplest and most efficient solution.


> See why I kept the fix on the backburner? :-)
>

:-P yes