Ink constructor

Ink({Key key, EdgeInsetsGeometry padding, Color color, Decoration decoration, double width, double height, Widget child })

Paints a decoration (which can be a simple color) on a Material.

The height and width values include the padding.

The color argument is a shorthand for decoration: new BoxDecoration(color: color), which means you cannot supply both a color and a decoration argument. If you want to have both a color and a decoration, you can pass the color as the color argument to the BoxDecoration.

Implementation 

Ink({
  Key key,
  this.padding,
  Color color,
  Decoration decoration,
  this.width,
  this.height,
  this.child,
}) : assert(padding == null || padding.isNonNegative),
     assert(decoration == null || decoration.debugAssertIsValid()),
     assert(color == null || decoration == null,
       'Cannot provide both a color and a decoration\n'
       'The color argument is just a shorthand for "decoration: new BoxDecoration(color: color)".'
     ),
     decoration = decoration ?? (color != null ? BoxDecoration(color: color) : null),
     super(key: key);