Question: My scroll has some views that is `cornerRadius = 10.0` and `masksToBounds = YES`.

This causes a performance issue for scrolling my scroll view. Though I tried each view's `shouldRasterize` is set `YES`, the issue is not solved.

However, I know the solution for this issue. That is what `masksToBound` is set `NO`. (`masksToBound's` default value is NO)
Although `masksToBound` is `NO`, my views's corners still have curve and the performance issue is solved, too.

I want to know about relation between `cornerRadius` and `masksToBounds`. I'm afraid of unexpected issues with this setting.

Thank you.

Answer: 
After providing `cornerRadius` which specifies a radius used to draw the rounded corners of the receiver’s background.

Now it depends on `masksToBounds` which determines if the sublayers are clipped to the receiver’s bounds. So if it is set to `YES`, an implicit mask matching the layer bounds is applied to the layer, including the effects of the `cornerRadius` property. If it is set to `YES` and a mask property is specified, the two masks are multiplied to get the actual mask values.

For example:

If you set that on a `CALayer` with image contents, the image will still be drawn outside the corner radius boundary. You can solve this by setting `sublayer.masksToBounds` to `YES`; but if you do that, the shadows won’t show up because they’ll be masked out!
There is not any specific relation ship .. actually when you call the Corner Radius it will crop the view at what radius you have passed and MaskToBound:Yes make it transparent to that part which you have cropped else it would be visible...