view 的Frame和bound

frame：指的是视图在父视图的坐标系统中的大小和位置。

bound：指的是视图在试图自己的坐标系统中的大小（位置起点是原点）。

center：指的是视图在父视图坐标系统中的中心点。

贴张苹果官网的图：

frame和bound的关系

下面这是其中一个发生变化，其他两个的变化，直接看吧，很浅显。

Although you can change the frame, bounds, and center properties independent of the others, changes to one property affect the others in the following ways:

• When you set the frame property, the size value in the bounds property changes to match the new size of the frame rectangle. The value in the center property similarly changes to match the new center point of the frame rectangle.

• When you set the center property, the origin value in the frame changes accordingly.

• When you set the size of the bounds property, the size value in the frame property changes to match the new size of the bounds rectangle.

By default, a view’s frame is not clipped to its superview’s frame. Thus, any subviews that lie outside of their superview’s frame are rendered in their entirety. You can change this behavior, though, by setting the superview’s clipsToBounds property to YES. Regardless of whether or not subviews are clipped visually, touch events always respect the bounds rectangle of the target view’s superview. In other words, touch events occurring in a part of a view that lies outside of its superview’s bounds rectangle are not delivered to that view.