code: protected RadialGradientPaint createSection3DEffectGradient(final int WIDTH, final float RADIUS_FACTOR) {
          final float[] FRACTIONS;
          final Color[] COLORS;
          if (isExpandedSectionsEnabled()) {
             FRACTIONS = new float[]{
                  0.0f,
                  0.7f,
                  0.75f,
                  0.96f,
                  1.0f
              };
  
              COLORS = new Color[]{
                  new Color(0.0f, 0.0f, 0.0f, 1.0f),
                  new Color(0.9f, 0.9f, 0.9f, 0.2f),
                  new Color(1.0f, 1.0f, 1.0f, 0.5f),
                  new Color(0.1843137255f, 0.1843137255f, 0.1843137255f, 0.3f),
                  new Color(0.0f, 0.0f, 0.0f, 0.2f)
              };
          } else {
             FRACTIONS = new float[]{
                  0.0f,
                  0.89f,
                  0.955f,
                  1.0f
              };
  
              COLORS = new Color[]{
                  new Color(0.0f, 0.0f, 0.0f, 0.0f),
                  new Color(0.0f, 0.0f, 0.0f, 0.3f),
                  new Color(1.0f, 1.0f, 1.0f, 0.6f),
                  new Color(0.0f, 0.0f, 0.0f, 0.4f)
              };
          }
  
  
  
          final Point2D GRADIENT_CENTER = new Point2D.Double(WIDTH / 2.0, WIDTH / 2.0);
  
          return new RadialGradientPaint(GRADIENT_CENTER, WIDTH * RADIUS_FACTOR, FRACTIONS, COLORS);
      }
docs: Returns a radial gradient paint that will be used as overlay for the track or section image
  to achieve some kind of a 3d effect.
  @param WIDTH
  @param RADIUS_FACTOR : 0.38f for the standard radial gauge
  @return a radial gradient paint that will be used as overlay for the track or section image