NSView - 如何在不重绘父视图的情况下重绘子视图

Question

I have a NSView with a sub view. I want to be able to redraw the sub view (call its drawRect) without redrawing the parent view. Is that possible?

When i case setNeedsDisplay on he sub view, drawRect of the parent view also called.

Answer 1

One thing you can do to reduce unnecessary drawing is overide -isOpaque and return YES.

Of course, you should only do this if the subview is in fact opaque.