public void setA ( final float a ) { if ( a < 0 || a > 1 ) { throw new InvalidValueException ( "a paramater accept values only from 0 to 255." ) ; } this . a = a ; rgba = "rgba(" + r + ", " + g + ", " + b + ", " + a + ")" ; if ( getStateChangeInformer ( ) != null ) { getStateChangeInformer ( ) . stateChanged ( this ) ; } }
to set alpha . The default value is 0 .