如何在C++框架集成中实现松散耦合？

// 接口头文件
class IRenderer {
public:
  virtual void Render() = 0;
};

// 具体实现头文件
class OpenGLRenderer : public IRenderer {
public:
  void Render() override {
    // OpenGL 渲染代码
  }
};

// 依赖注入类
class DependencyInjector {
public:
  std::shared_ptr<IRenderer> GetRenderer() {
    return std::make_shared<OpenGLRenderer>();
  }
};

// 使用依赖注入的类
class MyApplication {
public:
  MyApplication(std::shared_ptr<DependencyInjector> injector)
    : m_injector(injector) {}

  void Run() {
    auto renderer = m_injector->GetRenderer();
    renderer->Render();
  }

private:
  std::shared_ptr<DependencyInjector> m_injector;
};

// 接口头文件
class Shape {
public:
  virtual double GetArea() = 0;
};

// 具体实现头文件
class Rectangle : public Shape {
public:
  Rectangle(double width, double height)
    : m_width(width), m_height(height) {}

  double GetArea() override {
    return m_width * m_height;
  }

private:
  double m_width;
  double m_height;
};

class Circle : public Shape {
public:
  Circle(double radius)
    : m_radius(radius) {}

  double GetArea() override {
    return M_PI * m_radius * m_radius;
  }

private:
  double m_radius;
};

// 使用多态的类
class ShapeDrawer {
public:
  ShapeDrawer() {}

  void Draw(Shape& shape) {
    std::cout << "Drawing shape with area " << shape.GetArea() << std::endl;
  }
};

// 接口头文件
class IBook {
public: