Direct X uses interfaces to pass for example a device. As far as I know one interface is never mixed with another type of interface but I might be wrong about that. It is merely used as a way of communication between DX and the application. You cannot change the methods of it with inheritance because you only have the interface though. Therefore the helper or the wrapper.
No, the general case for an interface helper is a
single type helper for an interface as opposed to
multiple wrappers for the classes that support it....
So it is not
"the helper or the wrapper" but "the helper or the wrapper
s".
The ratio is that interfaces can be supported by classes that are otherwise completely unrelated.
I am kind of lazy, I prefer the interface helper. Get the point? Otherwise I will provide a simple example why this is the case.
A second ratio is, by application of the above:
If you examine the example that is now solved you will see that there is a parameter with a default value *before* a parameter without a default. Object Pascal does not support this, but with an interface helper we do....And actually in a far more readable way.
Technically it has no impact on the actual interface. It has only impact on the way the interface can be called. The default value somewhere in the middle of the parameter list is solved by the type helper.
Even for any unrelated class that supports the original interface... that contains a default in its definition... That's why it is so powerful.
Side note: I originally disapproved of this feature, but now I am convinced.