nstrackingarea.mm

//usr/bin/env clang++ $0 -o ${o=`mktemp`} -fmodules -fcxx-modules && echo $o && exec $o $* || exit

@import AppKit;

@interface View : NSView
@end

@implementation View
- (id)init
{
    if((self = [super initWithFrame:NSZeroRect])) {
        NSUInteger trackingOptions = NSTrackingActiveInActiveApp
            | NSTrackingMouseEnteredAndExited | NSTrackingCursorUpdate
            | NSTrackingMouseMoved;

        // Using NSTrackingInVisibleRect means AppKit will automatically synchronize the
        // tracking rect with changes in the view's visible area, so leave it undefined.
        trackingOptions |= NSTrackingInVisibleRect;
        static const NSRect trackingRect = NSZeroRect;

        [self addTrackingArea:[[[NSTrackingArea alloc] initWithRect:trackingRect
            options:trackingOptions owner:self userInfo:nil] autorelease]];
    }
    return self;
}

- (void)mouseEntered:(NSEvent *)event
{
    NSLog(@"mouseEntered");
}

- (void)mouseMoved:(NSEvent *)event
{
    NSLog(@"mouseMoved");
}

- (void)mouseExited:(NSEvent *)event
{
    NSLog(@"mouseExited");
}

- (void)updateTrackingAreas
{
    NSLog(@"updateTrackingAreas");
    [super updateTrackingAreas];
}
@end

int main()
{
    @autoreleasepool {
        [NSApplication sharedApplication];
        [NSApp setActivationPolicy:NSApplicationActivationPolicyRegular];

        id appMenu = [[NSMenu new] autorelease];
        [appMenu addItem:[[[NSMenuItem alloc] initWithTitle:@"Quit"
            action:@selector(terminate:) keyEquivalent:@"q"] autorelease]];
        id appMenuItem = [[NSMenuItem new] autorelease];
        [appMenuItem setSubmenu:appMenu];
        NSApp.mainMenu = [[NSMenu new] autorelease];
        [NSApp.mainMenu addItem:appMenuItem];

        NSWindow *window = [[NSWindow alloc] initWithContentRect:NSMakeRect(0, 0, 500, 500)
            styleMask:NSWindowStyleMaskTitled | NSWindowStyleMaskClosable | NSWindowStyleMaskResizable
            backing:NSBackingStoreBuffered defer:YES];

        window.contentView = [[View alloc] init];
        window.title = @"NSTrackingArea testcase";

        [window center];
        [window makeKeyAndOrderFront:nil];
        [NSApp activateIgnoringOtherApps:YES];
        [NSApp run];
        return 0;
    }

}