CALayer帧动画
_sunLayer = [[CALayer alloc]init];
_sunLayer.contents = (id)[UIImage imageNamed:@"sun"].CGImage;
_sunLayer.bounds = CGRectMake(0, 0, 40, 40);
_sunLayer.position = CGPointMake(100, 200);
[self.layer addSublayer:_sunLayer];
CAKeyframeAnimation *keyframe = [CAKeyframeAnimation animationWithKeyPath:@"position"];//帧动画-位移
CGMutablePathRef path = CGPathCreateMutable();
CGPathMoveToPoint(path, NULL, _sunLayer.position.x, _sunLayer.position.y);//移动到起始点
CGPathAddEllipseInRect(path, NULL, CGRectMake(100, 200, 200, 200));
keyframe.path = path;//路径
[keyframe setCalculationMode:kCAAnimationPaced];//加上不会停顿
keyframe.duration = 2.0;//时间
keyframe.repeatCount = HUGE_VAL;//重复-无限重复
[_sunLayer addAnimation:keyframe forKey:@"fsfsf"];