理解模型树-呈现树-渲染树

···

• (void)testLayer{
  UIView *view = [[UIView alloc] init];
  view.backgroundColor = [UIColor orangeColor];
  view.frame = CGRectMake(0, 0, 50, 50);
  [self.view addSubview:view];
  [UIView animateWithDuration:5 animations:^{
  view.frame = CGRectMake(100, 100, 50, 50);
  }];
  //modelayer presentlayer
  NSLog(@"frame:%f",view.frame.origin.x);
  }
  ···