CAGradientLayer *gradient = [CAGradientLayer layer];
        gradient.frame = button.bounds;

        CGFloat x = 71./360; //71度
        float a = pow(sinf((2*M_PI*((x+0.75)/2))),2);
        float b = pow(sinf((2*M_PI*((x+0.0)/2))),2);
        float c = pow(sinf((2*M_PI*((x+0.25)/2))),2);
        float d = pow(sinf((2*M_PI*((x+0.5)/2))),2);

        [gradient setStartPoint:CGPointMake(a, b)];
        [gradient setEndPoint:CGPointMake(c, d)];

        gradient.colors = @[(__bridge id)UIColorFromRGBWithAlpha(0x16E05A,1.0).CGColor,
                             (__bridge id)UIColorFromRGBWithAlpha(0x16E09D,1.0).CGColor];

        [button.layer insertSublayer:gradient atIndex:0];