坐标系的转换

转换坐标系就是本来中间那个家伙是以左边那个家伙为坐标系的,现在变为以右边那个家伙为坐标系,它的坐标变为多少,就是中间那个控件以右边那个控件为坐标的位置(最后的结果就是两个坐标系的x和y值之间的差别高度和宽度不变)

// 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];{60,70,50,50}

    // 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];{60,70,50,50}

    

    // 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));

}