Enable Layers to Have Clear Backgrounds

[TheCedarPrince]

Is your feature request related to a problem? Please explain.

Layers are cool - let's make them even cooler by adding in transparency. 🕶️

Describe the solution you'd like

Ideally, I would like layers to have the ability to have fully transparent backgrounds. The objects on this layer wouldn't be transparent but rather, everything but the objects would be.

Describe alternatives you've considered

One could make the backgrounds for each layer match the global layer but that isn't actual transparency but rather camoflauge.

Additional context

Perhaps the logic could work like:

1. Set opacity = :transparent
2. Determine where on each layer matrices are default values
3. Compare them with the global layer
4. If a coordinate is defined in the global layer, set the value in the layer to that value
5. If not, keep the default empty value.
6. Otherwise, if layer defines a value at a coordinate, put the value in that layer there as precedent.

Little vague so will have to think of it some more!

[Sov-trotter]

I am not sure if I understand this correctly but if we don't define a Background in the layer's begin...end block, it does end up being fully transparent. In fact the entire drawing that holds all the layers is itself transparent.

[TheCedarPrince]

Hey @Sov-trotter - just ignore this issue for now. Just was putting it here before I forgot. :)

[Wikunia]

Can we close this @TheCedarPrince ? It's possible in #342 to set :opaque or :transparent now

[TheCedarPrince]

Sure! I have been watching that discussion on #342 with excitement as I see we are getting this functionality. :)