> On Feb 24, 2016, at 1:44 PM, Graham Cox <graham....@bigpond.com> wrote: > > >> On 24 Feb 2016, at 11:08 PM, Charles Jenkins <cejw...@gmail.com> wrote: >> >> My guess is, you do this by adding a mask layer; but you probably don’t >> redraw the mask in drawRect(), hm? It should never need to be refreshed >> unless the bounds change. > > > Can you not just use a clipping path? They’re usually much easier to set up > especially for simple cases like this than a mask layer. > > e.g. the simplest way I can think of drawing this is a) draw your image at > the correct size and position, b) form a clipping path from the bounds rect > plus the desired circle, setting the winding rule if necessary so that the > path includes all of the area of your view EXCEPT the circle. c) paint over > the entire view in a solid colour (black I think you said). The clipping path > ensures that you won’t paint over the circular aperture that shows the image. > >> Assuming I can figure out how to make a mask layer, what is the correct way >> to monitor for a bounds change in order to recreate the mask? > > > Override -setFrame:, call super then do what you need to do.
-layoutSubviews would be better, as in general if you need to override -setFrame: for something, you also need to override -setCenter: and -setBounds:. If you need to ensure animation works, you can call -layoutIfNeeded inside of your animation block. But since your drawing something, a clipping view isn’t necessary – you can just clip your drawing. > > However, if you use a clipping path, you can just create this on the fly as > part of -drawRect: and so it’ll always be correct, and you won’t need to do > this. There’s no reason to cache this path unless it’s really complex and > expensive. Hint: it’s not, it’s a circle. > > —Graham > > -- David Duncan _______________________________________________ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
