Shadow constructor
Construct a shadow.
The default shadow is a black shadow with zero offset and zero blur. Default shadows should be completely covered by the casting element, and not be visible.
Transparency should be adjusted through the color
alpha.
Shadow order matters due to compositing multiple translucent objects not being commutative.
Implementation
const Shadow({
this.color = const Color(_kColorDefault),
this.offset = Offset.zero,
this.blurRadius = 0.0,
}) : assert(color != null, 'Text shadow color was null.'), // ignore: unnecessary_null_comparison
assert(offset != null, 'Text shadow offset was null.'), // ignore: unnecessary_null_comparison
assert(blurRadius >= 0.0, 'Text shadow blur radius should be non-negative.');