[whatwg] CanvasRenderingContext2D with addPath, currentPath

Dirk Schulze dschulze at adobe.com
Mon Nov 4 10:36:48 PST 2013

On Nov 3, 2013, at 3:22 PM, Glenn Maynard <glenn at zewt.org> wrote:

> On Sat, Nov 2, 2013 at 9:03 PM, Rik Cabanier <cabanier at gmail.com> wrote:
>>> Does this mean that ctx.currentPath != ctx.currentPath?
>> Yes
>>> That's bad!
>> Why would it be bad (apart from being different)?
> It's strange to say "foo.bar.baz = 1" (ctx.currentPath.baz = 1), and for
> foo.bar.baz to not be 1 the next time you look.  It's also confusing if you
> use it as a Map key.

I think the problem that the UA would be focused with is the following:

var path = ctx1.currentPath;
ctx2.currentPath = path;

or simply

ctx2.currentPath = ctx1.currentPath

Both contexts could manipulate the same path and both can have different CTMs which also change independent of each other. Mixing that up could cause a huge mess.

That is one of the reasons why WebKit creates copies.


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