CAKeyframeAnimation－关键帧动画

//关键帧动画 CAKeyframeAnimation
- (void)keyAnimation{
CALayer *layer =[CALayer layer];
layer.bounds = CGRectMake(0, 0, 100, 100);
layer.position = CGPointMake(100,100);
layer.backgroundColor = [UIColor yellowColor].CGColor;
[self.view.layer addSublayer:layer];

CAKeyframeAnimation *anim = [CAKeyframeAnimation animation];
anim.keyPath = @"position";
anim.removedOnCompletion = NO;
anim.fillMode = kCAFillModeForwards;
anim.duration = 2.0;

CGMutablePathRef path = CGPathCreateMutable();
CGPathAddEllipseInRect(path, NULL, CGRectMake(100, 100, 200, 200));
anim.path = path;
CGPathRelease(path);

// 设置动画的执行节奏
// kCAMediaTimingFunctionEaseInEaseOut : 一开始比较慢, 中间会加速,  临近结束的时候, 会变慢
anim.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut];
anim.delegate = self;

[layer addAnimation:anim forKey:nil];

}