Does Canvas class in android follow any Design Pattern? Or its violating OCP?

I am studying about design pattern and gone through the code of Canvas.java in android sdk. First of all it contains thousand of lines of code, is it right of having this much of line in a class? And my second point is it has some methods like drawCircle(), drawRectangle() etc in same class. So is this pattern is right to do so.

As I am beginner to designing code and architecture, it will very helpful if someone put some light on this.

Hope my question is relevant on this portal.