I have a controller for a "settings view" in where the user changes some of the properties of what's drawn in my MyView view. But, I can't figure out how to call setNeedsDisplay on MyView instead of my SettingsView. 

MyView is an UIView, and it has its own controller called MyViewController. 

Inside this view, I'm drawing rectangles of a kind, and with different colors. In SettingsViewController I change a parameter which affects what kind of rectangles are drawn in MyView. However, for that to happen, the user has to (they're on different tabs) switch views, and perform some action so that setNeedsDisplay gets called. I'm trying to call setNeedsDisplay FROM SettingsViewController, but I can't do self.view setNeedsDisplay beacause it'll call setNeedsDisplay on MyView. Does this make more sense?