Tells the delegate that the image object is unable, for whatever reason, to lock focus on its image or draw in the specified rectangle.
- macOS 10.0+
NSImageobject that encountered the problem.
The rectangle that the image object was attempting to draw.
NSImage to draw in place of the one in
nil if the delegate wants to draw the image itself.
The delegate can do one of the following:
NSImageobject to draw in the sender’s place.
Draw the image itself and return
nilto indicate that
sendershould give up on the attempt at drawing the image.