code: public static final Color blend (Color c1, Color c2, float firstperc)
      {
          float p2 = 1.0f - firstperc;
          return new Color((int) (c1.getRed() * firstperc + c2.getRed() * p2),
                   (int) (c1.getGreen() * firstperc + c2.getGreen() * p2),
                   (int) (c1.getBlue() * firstperc + c2.getBlue() * p2));
      }
docs: Blends the two supplied colors, using the supplied percentage
  as the amount of the first color to use.
  
  @param firstperc The percentage of the first color to use, from 0.0f
  to 1.0f inclusive.