I want to replicate the background of dock Stacks in grid and list mode. The background is translucent black with a blur effect:
The problem is that [CALayer backgroundFilters] only applies to content in the window, the filters are not applied to content in other windows. Here's my code:
- (void)applicationDidFinishLaunching:(NSNotification *)aNotification
{
//make window transparent
self.window.backgroundColor = [NSColor clearColor];
[self.window setOpaque:NO];
[self.window setHasShadow:NO];
[self.window setStyleMask:NSBorderlessWindowMask];
//make the content view layer hosting
CALayer *rootLayer = [CALayer layer];
[[self.window contentView] setLayer:rootLayer];
[[self.window contentView] setWantsLayer:YES];
//blur the background contents - NOT WORKING!
[rootLayer setBackgroundColor:CGColorCreateGenericGray(0.0, .716)];
CIFilter *blurFilter = [CIFilter filterWithName:@"CIGaussianBlur"];
[blurFilter setDefaults];
[rootLayer setBackgroundFilters:[NSArray arrayWithObject: blurFilter]];
}
I can't think of how else to achieve this effect. (I've taken a look at the Display Services to see if there are any useful functions but I can't see any.)
Any ideas?
There is private API available this. Here is sample code by Rob Keniger:
In 10.5 you can add any core image filter to a window using the private function '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 );
}