random color

random.m

- (UIColor *)randomColor
{
  return [self randomColorWithAlpha:1.0f];
}

- (UIColor *)randomColorWithAlpha:(CGFloat)alpha
{
  CGFloat hue = (arc4random() % 256 / 256.0 );
  CGFloat saturation = (arc4random() % 128 / 256.0 ) + 0.5;
  CGFloat brightness = (arc4random() % 128 / 256.0 ) + 0.5;
  return [UIColor colorWithHue:hue saturation:saturation brightness:brightness alpha:alpha];
}