public void darkerColor(int factor){
  int color=getColor();
  int r=color >> 16 & 0xff;
  int g=color >> 8 & 0xff;
  int b=color & 0xff;
  r=Math.max(0,r - factor);
  g=Math.max(0,g - factor);
  b=Math.max(0,b - factor);
  setColor(((r << 16) & 0xff0000) | ((g << 8) & 0xff00) | (b & 0xff));
}

public void darkerColor ( int factor ) { int color = getColor ( ) ; int r = color > > 16 & 0xff ; int g = color > > 8 & 0xff ; int b = color & 0xff ; r = Math . max ( 0 , r - factor ) ; g = Math . max ( 0 , g - factor ) ; b = Math . max ( 0 , b - factor ) ; setColor ( ( ( r << 16 ) & 0xff0000 ) | ( ( g << 8 ) & 0xff00 ) | ( b & 0xff ) ) ; }
makes the current color slightly darker , this is useful for many visual effects
