# 桥模式

**将一个事物的两个维度分离，使其都可以独立地变化，如画图程序形状和颜色**

```python
from abc import ABCMeta, abstractmethod

class Shape(metaclass=ABCMeta):
    # 组合方式进行耦合 - 松耦合
    def __init__(self, color):
        self.color = color

    @abstractmethod
    def draw(self):
        pass

class Color(metaclass=ABCMeta):
    @abstractmethod
    def paint(self, shape):
        pass

class Rectangle(Shape):
    name = '长方形'

    def draw(self):
        self.color.paint(self)

class Circle(Shape):
    name = '圆形'

    def draw(self):
        self.color.paint(self)

class Red(Color):
    def paint(self, shape):
        print('红色的%s' % shape.name)

class Green(Color):
    def paint(self, shape):
        print('绿色的%s' % shape.name)

shape = Rectangle(Red())
shape.draw()

shape2 = Circle(Green())
shape2.draw()
```

**应用场景：** 

当事物有两个维度上的表现，两个维度都可能扩展

优**点：**

* 抽象与实现分离
* 优秀的扩展能力


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