iOS 坐标转换

首先添加一个redView和一个greenView，其中greenView是添加到redView上面。

UIView * redView = [[UIView alloc]initWithFrame:CGRectMake(0, 64, 300, 300)]; 

redView.backgroundColor = [UIColor redColor];

 [self.view addSubview:redView]; UIView * greenView = [[UIView alloc]initWithFrame:CGRectMake(0, 0, 100, 100)]; 

greenView.backgroundColor = [UIColor greenColor]; 

[redView addSubview:greenView]; 

NSLog(@"----redView在self.view的中frame:%@",NSStringFromCGRect(redView.frame)); 

NSLog(@"----greenView在redView的中frame:%@",NSStringFromCGRect(greenView.frame)); 

现在要将greenView在redView的frame ---> self.view 转换计算，方法有以下两种：

方法1  调用- (CGRect)convertRect:(CGRect)rect toView:(nullable UIView *)view; convertRect:待转换的view的frame 或者bounds toView:目标坐标系参考view，如果传nil，就是以当前window为参考系 调用者：原rect所在坐标系统的直接关联view 这里greenView.frame 原来是参照父控件（superview）redView计算坐标的 如果传入的是greenView.bounds，那么是参考其自身计算坐标的，调用者就是greenView 

CGRect RectInView1= [redView convertRect:greenView.frame toView:self.view];

CGRect RectInView2= [greenView convertRect:greenView.bounds toView:self.view]; 

CGRect RectInView3= [greenView.superview convertRect:greenView.frame toView:self.view]; 

NSLog(@"将greenView在self.view的frame ---> self.view :%@",NSStringFromCGRect(RectInView1)); 

NSLog(@"将greenView在self.view的frame2 ---> self.view :%@",NSStringFromCGRect(RectInView2));

 NSLog(@"将greenView在self.view的frame3 ---> self.view :%@",NSStringFromCGRect(RectInView3)); 

方法2 调用 - (CGRect)convertRect:(CGRect)rect fromView:(nullable UIView *)view;

CGRect RectFromView1 = [self.view convertRect:greenView.frame fromView:redView]; 

CGRect RectFromView2 = [self.view convertRect:greenView.bounds fromView:greenView]; 

CGRect RectFromView3 = [self.view convertRect:greenView.frame fromView:greenView.superview];

 NSLog(@"将greenView在self.view的frame3 ---> self.view :%@",NSStringFromCGRect(RectFromView1)); 

NSLog(@"将greenView在self.view的frame4 ---> self.view :%@",NSStringFromCGRect(RectFromView2));

打印结果：