iOS开发---转换坐标系

- (void)viewDidLoad
{
    [super viewDidLoad];
    
    // 蓝色
    UIView *blue = [[UIView alloc] init];
    blue.backgroundColor = [UIColor blueColor];
    blue.frame = CGRectMake(0, 50, 200, 200);
    [self.view addSubview:blue];
    self.blue = blue;
    
    // 红色
    UIView *red = [[UIView alloc] init];
    red.backgroundColor = [UIColor redColor];
    red.frame = CGRectMake(50, 60, 100, 100);
    [blue addSubview:red];
    self.red = red;
    
    // 黄色
    UIView *yellow = [[UIView alloc] init];
    yellow.backgroundColor = [UIColor yellowColor];
    yellow.frame = CGRectMake(10, 10, 50, 50);
    [red addSubview:yellow];
    self.yellow = yellow;
    
    // 紫色
    UIView *purple = [[UIView alloc] init];
    purple.backgroundColor = [UIColor purpleColor];
    purple.frame = CGRectMake(150, 350, 100, 100);
    [self.view addSubview:purple];
    self.purple = purple;
}

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
//    NSLog(@"%@", NSStringFromCGRect(self.yellow.bounds));
//    NSLog(@"%@", NSStringFromCGRect(self.yellow.frame));
    
    // 计算self.yellow在self.blue中的位置和尺寸
//    CGRect newRect = [self.yellow convertRect:self.yellow.bounds toView:self.blue];
    
    
    // 计算self.yellow在self.purple中的位置和尺寸
//    CGRect newRect = [self.yellow.superview convertRect:self.yellow.frame toView:self.purple];
    
    // 计算self.red在self.yellow中的位置和尺寸
    //    CGRect newRect = [self.red convertRect:self.red.bounds toView:self.yellow];
    // 计算self.red在self.yellow中的位置和尺寸
//    CGRect newRect = [self.yellow convertRect:self.red.bounds fromView:self.red];
    
    // 计算self.red在屏幕中的位置和尺寸(nil代表屏幕)
    CGRect newRect = [self.red convertRect:self.red.bounds toView:nil];
    NSLog(@"%@", NSStringFromCGRect(newRect));
}