Group Rewrite Proposal

[ShaMan123]

I was thinking of a next generation for Group in light of issues and features I need working in nested objects (e.g. #7130 #7142).
I wanted to understand the considerations that lead to designing Group as it is. In particular, why does Group transform objects to group's coordinate plane and not a different approach?
I have in mind an object, let's call it DrawingGroup | VirtualGroup, that will extend Collection and it's functionality will differ from Group in one major aspect. It will pre-transform the rendering context so that all objects will remain in the canvas coordinate plane. It will need Group resizing logic as well as a mechanism to apply transformations to it's objects.
I think this will fix lots of issues regarding geometry and more for nested objects and will unlock powerful features with ease (e.g. #6776) and can eventually deprecate Group.
@asturur what do you think?
I saw #6316 that has an interesting solution as well.

[asturur]

fabric.Group was here before i joined, so pre 2014.
Probably it was designed so that it could work.
There was no caching, objects had to be drawn all each render so having the objects recentered around the group was a way to do so.

Group has virtually no features apart add and remove.
So if we want to try to create a better container with a different name and then eventually swap or rename, that is totally doable.

I understand that having the objects changing coordinates when grouped is boring and is an annoyance.

[ShaMan123]

I tried #7316. IMO it can't serve as a viable solution. There are too many cases that need ugly workarounds.

[asturur]

What are the cases? the Layer can complement the Group.
The group can loose some functionality and the Layer can have some but not all.

[ShaMan123]

I agree with all except:

they are still in the stack of the canvas

The objects should be in the layer stack IMO.
However they should be individually selected and the layer should be selectable as well in some manner of UX

[asturur]

ok so let's forget selecting for now and let's build a prototype of this Layer that render objects as a group but without touching top and left and acoords.
That would be the first step, even if it does not work.
Let's make it in a branch, so we can merge quickly

[ShaMan123]

#7316

[ShaMan123]

I'll add that I think it should render as Rect does, with options like fill and shadow

[asturur]

That wouldn't be a layer. You can set shadow to all objects.

[ShaMan123]

#7449