多个UIBezierPath拼接起来的运动轨迹，在执行动画的时候，动画出现卡顿，

Question

要实现动画的所设置的路径代码：

- (void)drawRect:(CGRect)rect {

    UIColor *color = [UIColor redColor];
    [color set];
    _aPath = [UIBezierPath bezierPath];
        [_aPath addArcWithCenter:CGPointMake(self.center.x, self.center.y-50) radius:50 startAngle:M_PI_2 endAngle:M_PI*2.f*3/4 clockwise:YES];
        [_aPath addArcWithCenter:CGPointMake(self.center.x, self.center.y) radius:100 startAngle:-M_PI_2 endAngle:M_PI*2.f*3/4 clockwise:YES];
        [_aPath addArcWithCenter:CGPointMake(self.center.x, self.center.y) radius:100 startAngle:-M_PI_2 endAngle:M_PI*2.f*3/4/3 clockwise:YES];
        [_aPath addArcWithCenter:CGPointMake(self.center.x, self.center.y+50) radius:50 startAngle:M_PI_2 endAngle:M_PI*2.f*3/4 clockwise:YES];

    _aPath.lineWidth = 5.0;
    _aPath.lineCapStyle = kCGLineCapRound; //线条拐角
   _aPath.lineJoinStyle = kCGLineCapRound; //终点处理
    [_aPath stroke];
}

下面的是我执行动画代码：

CAKeyframeAnimation *keyframeAnimation=[CAKeyframeAnimation animationWithKeyPath:@"position"];
    keyframeAnimation.path = dr.aPath.CGPath;
    keyframeAnimation.repeatCount=1;
    keyframeAnimation.removedOnCompletion = NO;
    keyframeAnimation.fillMode = kCAFillModeForwards;
    keyframeAnimation.duration = 4.0f;
    keyframeAnimation.timingFunction=[CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut];
    keyframeAnimation.delegate=self;
    [imageView.layer addAnimation:keyframeAnimation forKey:nil];

Answer 1

在执行动画的时候，动画出现卡顿

如果“卡顿”指的是它中间会停下来的话，那是因为插值方式。默认的插值方式是kCAAnimationLinear，关键帧直线相连进行插值。要想让动画连续进行，可以简单加一句：

keyframeAnimation.calculationMode = kCAAnimationPaced;

有更精细的需求，可以自己用keyTimes和timingFunctions来控制。