This is an attribute that specifies a color. The value of this
attribute is an array of four doubles in the form
{red, green, blue, alpha}, where each number is the range of 0.0
to 1.0. The 'alpha' term represents opacity, where 1.0 is opaque,
and 0.0 is fully transparent (invisible).
Edward A. Lee
$Id: ColorAttribute.java 70402 2014-10-23 00:52:20Z cxh $
Ptolemy II 4.0
Yellow (eal)
Red (cxh)