code: private int getColorDigit( int idx, CssFormatter formatter ) {
          Expression expression = get( idx );
          double d = expression.doubleValue( formatter );
          if( expression.getDataType( formatter ) == PERCENT ) {
              d *= 2.55;
          }
          return colorDigit(d);
      }
docs: Get the idx parameter from the parameter list as color digit.
  
  @param idx
  the index starting with 0
  @param formatter
  current formatter
  @return the expression