Difference between Bridge pattern and Adapter pattern

Question

What is the difference between the Bridge and Adapter patterns?

Answer 1

Suppose you've a abstract Shape class with a (generic/abstracted) drawing functionality and a Circle who implements the Shape. Bridge pattern simply is a two-way abstraction approach to decouple the implementation ( drawing in Circle ) and generic/abstracted functionality ( drawing in the Shape class ).

What does it really mean? At a first glance, it sounds like a something you already making ( by dependency inversion). So no worries about having a less-ridig or more modular code base. But it's a bit deeper philosophy behind it.

From my understanding, the need of usage pattern might emerge when I need to add new classes which are closely related with the current system ( like RedCircle or GreenCircle ) and which they differ by only a single functionality ( like color ). And I'm gonna need Bridge pattern particularly if the existing system classes ( Circle or Shape ) are to be frequently changed and you don't want newly added classes to be affected from those changes. So that's why the generic drawing functionality is abstracted away into a new interface so that you can alter the drawing behaviour independent from Shape or Circle.