getColor method
Create a Color object with the format and number of channels of the image.
Implementation
@override
Color getColor(num r, num g, num b, [num? a]) => a == null
? ColorRgb8(r.clamp(0, 255).toInt(), g.clamp(0, 255).toInt(),
b.clamp(0, 255).toInt())
: ColorRgba8(r.clamp(0, 255).toInt(), g.clamp(0, 255).toInt(),
b.clamp(0, 255).toInt(), a.clamp(0, 255).toInt());