iOS position(位置)和anchorPoint(锚点)

参考自：

https://www.jianshu.com/p/0dfccd073ae0

https://www.cnblogs.com/kingbo/p/7162364.html

 

    CALayer *MamiLayer = [CALayer layer];
    MamiLayer.backgroundColor = [UIColor orangeColor].CGColor;
    MamiLayer.bounds = CGRectMake(0, 0, 100, 100);
    MamiLayer.position = CGPointMake(self.view.frame.size.width / 2, self.view.frame.size.height /2);
    MamiLayer.anchorPoint=CGPointMake(0, 1);
    [self.view.layer addSublayer:MamiLayer];
    NSLog(@"MamiLayer.position =>( %f,%f )",MamiLayer.position.x,MamiLayer.position.y);
    
    CALayer *MamiLayer2 = [CALayer layer];
        MamiLayer2.backgroundColor = [UIColor redColor].CGColor;
        MamiLayer2.bounds = CGRectMake(0, 0, 100, 100);
        MamiLayer2.position = CGPointMake(self.view.frame.size.width / 2, self.view.frame.size.height /2);
    //    MamiLayer.anchorPoint=CGPointMake(0.3, 0.3);
        [self.view.layer addSublayer:MamiLayer2];

1. position相当于UIView视图中的center，是layer视图的中心点。

2. 确实设置了anchorPoint ， position 是不会改变的。

3. 我的理解就是，设置anchorPoint在哪，就把anchorPoint 放到 position 的位置。就得到结果视图的位置。这是个逆推的过程。