Understand convertRect:toView:, convertRect:FromView:, convertPoint:toView: and convertPoint:fromView: methods

I'm trying to understand the functionalities of these methods. Could you provide me with a simple use case to understand their semantics?

From the documentation, for example, convertPoint:fromView: method is described as follows:

Converts a point from the coordinate system of a given view to that of the receiver.

What does the coordinate system mean? What about the receiver?

For example, does it make sense using convertPoint:fromView: like the following?

CGPoint p = [view1 convertPoint:view1.center fromView:view1];

Using NSLog utility, I've verified that p value coincides with view1's center.

Thank you in advance.

EDIT: For those interested, I've created a simple code snippet to understand these methods.

UIView* view1 = [[UIView alloc] initWithFrame:CGRectMake(100, 100, 150, 200)];
view1.backgroundColor = [UIColor redColor];
    
NSLog(@"view1 frame: %@", NSStringFromCGRect(view1.frame));        
NSLog(@"view1 center: %@", NSStringFromCGPoint(view1.center));   
    
CGPoint originInWindowCoordinates = [self.window convertPoint:view1.bounds.origin fromView:view1];        
NSLog(@"convertPoint:fromView: %@", NSStringFromCGPoint(originInWindowCoordinates));
    
CGPoint originInView1Coordinates = [self.window convertPoint:view1.frame.origin toView:view1];        
NSLog(@"convertPoint:toView: %@", NSStringFromCGPoint(originInView1Coordinates));

In both cases self.window is the receiver. But there is a difference. In the first case the convertPoint parameter is expressed in view1 coordinates. The output is the following:

convertPoint:fromView: {100, 100}

In the second one, instead, convertPoint is expresse