Доступен приватный API.Вот пример кода Роба Кенигера:
В 10.5 вы можете добавить любой основной фильтр изображений в окно, используя закрытую функцию 'CGSAddWindowFilter'.
typedef void * CGSConnectionID;
extern OSStatus CGSNewConnection(const void **attr, CGSConnectionID *id);
- (void)enableBlurForWindow:(NSWindow *)window
{
CGSConnectionID _myConnection;
uint32_t __compositingFilter;
int __compositingType = 1; // Apply filter to contents underneath the window, then draw window normally on top
/* Make a new connection to CoreGraphics, alternatively you could use the main connection*/
CGSNewConnection(NULL , &_myConnection);
/* The following creates a new CoreImage filter, then sets its options with a dictionary of values*/
CGSNewCIFilterByName (_myConnection, (CFStringRef)@"CIGaussianBlur", &__compositingFilter);
NSDictionary *optionsDict = [NSDictionary dictionaryWithObject:[NSNumber numberWithFloat:3.0] forKey:@"inputRadius"];
CGSSetCIFilterValuesFromDictionary(_myConnection, __compositingFilter, (CFDictionaryRef)optionsDict);
/* Now just switch on the filter for the window */
CGSAddWindowFilter(_myConnection, [window windowNumber], __compositingFilter, __compositingType );
}