Block Mac UI controls painting/redrawing

Question

Hello I was wondering if anyone could shed some light how I may enable/disable redrawing of any class inherited from a nsview?

I know Windows has a message you can send to a hwnd to enable/disable gadget painting messages. This also then propagates to child hwnds too. Is there an equivalent method in Mac development?

I have an existing GUI library and I was wondering if there is a method to do this that doesn't require modification of the existing source code?

Answer 1

If the problem is that you're doing a lot of control layout work and don't want drawing to occur while this is happening, you can use either [NSWindow disableScreenUpdatesUntilFlush] or the global NSDisableScreenUpdates() and NSEnableScreenUpdates() functions to prevent the screen updating until you're ready.

Answer 2

I am not sure exactly what you are trying to do, but imagine you have an NSView subclass that has a draw method

.h

BOOL shouldDraw;

.m

-(void)drawRect:(NSRect)someRect
{
    if(shouldDraw)
    {
        [super drawRect:someRect];
    }
}

if you never call super's implementation of draw, nothing will get drawn.