shadow
Casts a blurred shadow of everything inside it, into outsets the component grows by.
The shadow is the content's own silhouette, not a declared outline: everything declared after it, tinted, blurred and laid down behind it. Rounded corners, a cut-out, a line of text - whatever the content's edge is, the shadow has it.
The outsets the blur needs are this step's outsets. A Foundation container grows the component's bounds by them while its layout bounds stay; any other parent clips what is painted past the bounds. paintOutsets(PaintOutsets.None) gives them layout space under either. See "Bounds" in docs/FOUNDATION.md.
Return
this chain with the shadow declared on it.
Parameters
how far the silhouette is spread, in the component's own units; 0 or less casts a hard edge.
the shadow's fill, usually translucent.
how far the shadow moves right of what casts it.
how far the shadow moves below what casts it.