code: function( t ){
              var idx;
              if( this.colors.size() > 2 ){
                  idx = Math.floor( this.map.getClippedValueFor(t) + 0.5 );
              } else {
                  idx = t >= this.map.getInputMedian() ? 1 : 0;
              }
              return this.colors.get(idx);
          }
docs: get a color from a tonal value
  @param {Number} t
  @return {toxi.color.TColor}