Re: Fwd: [whatwg] Drawing shapes on canvas

On 2/17/2014 2:58 PM, Rik Cabanier wrote:
>
>>           Shape2D add(Shape2D); // returns a path that is the union
>>         of the 2 paths
>>         }
>>
>>     This class will represent a painted area. Because it knows the
>>     winding and stroking rules, the browser will be able to do
>>     expensive math in advance. It can also cache the region on the GPU.
>>     constructors:
>     ...
>>
>>     1:
>>     http://blogs.adobe.com/webplatform/2013/01/31/revised-canvas-paths/
>
>
>     This proposal is an improvement on the current direction of the
>     Path object.
>
>     The long-form constructor feels a little tedious/difficult, with 8
>     arguments to be passed.
>     I'd like to see xor / remove as well, if you're going to have
>     "add" on the Shape2D method.
>
>
> Yes.
> I left it out since those operators aren't easily emulated.
> If we had access to an open source library that could calculate this 
> correctly and in an efficient way, it can be added again.

Need more info here. "Implemented" v. emulated.
What is your level of accuracy for "correctly".

Is this a rasterization API or a Path API?

A rasterizer could run a simple bitmap xor/and prior to fill, a Path API 
would need to, in some possible future, return a path.

We've implemented these before, they're not particular hard, but there 
are certainly some issues around precision when it comes to curves.

Glad to have the discussion.

-Charles