how to get window with semi-transparent blurred background

Question

I'd like to get a window that has a semi-transparent blurred background, just like what the Terminal can do. See this video, about 30 sec in, to see what I mean: http://www.youtube.com/watch?v=zo8KPRY6-Mk

See an image here: http://osxdaily.com/wp-content/uploads/2011/04/mac-os-x-lion-terminal.jpg

I've been googling for an hour, and can't get anything to work. I believe I need to somehow create a core animation layer and add a background filter, but I've been unsuccessful so far... I just see the gray background of my window. Here's the code I've got so far:

Code:

//  Get the content view -- everything but the titlebar.
NSView *theView = [[self window] contentView];
[theView setAlphaValue:0.5];

// Create core animation layer, with filter
CALayer *backgroundLayer = [CALayer layer];
[theView setWantsLayer:YES];
[theView setLayer:backgroundLayer]; 
CIFilter *blurFilter = [CIFilter filterWithName:@"CIGaussianBlur"];
[blurFilter setDefaults];
[theView layer].backgroundFilters = [NSArray arrayWithObject:blurFilter];  
[[theView layer] setBackgroundFilters:[NSArray arrayWithObject:blurFilter]];

Any tips or examples to do what I'm trying to do? Thanks!

Answer 1

no need for layers and filters, NSWindow can do it itself

[mywindow setOpaque:NO];
[mywindow setBackgroundColor: [NSColor colorWithCalibratedHue:0.0 saturation:0.0 brightness:0.2 alpha:0.5]];

please do not use this, as it will alpha your title bar also (post it here just in case others need)

[mywindow setOpaque:NO];
[mywindow setBackgroundColor: [NSColor blackColor]];
[mywindow setAlphaValue:0.5];

Answer 2

For the transparency use Jiulong Zhao's suggestion.

For a blurred background use this

The call on a NSWindow :

[self enableBlurForWindow:self];

The function :

-(void)enableBlurForWindow:(NSWindow *)window
{
    //!!!! Uses private API - copied from http://blog.steventroughtonsmith.com/2008/03/using-core-image-filters-onunder.html

    CGSConnection thisConnection;
    uint32_t compositingFilter;
    int compositingType = 1; // Under the window

    /* Make a new connection to CoreGraphics */
    CGSNewConnection(NULL, &thisConnection);

    /* Create a CoreImage filter and set it up */
    CGSNewCIFilterByName(thisConnection, (CFStringRef)@"CIGaussianBlur", &compositingFilter);
    NSDictionary *options = [NSDictionary dictionaryWithObject:[NSNumber numberWithFloat:2.0] forKey:@"inputRadius"];
    CGSSetCIFilterValuesFromDictionary(thisConnection, compositingFilter, (__bridge CFDictionaryRef)options);

    /* Now apply the filter to the window */
    CGSAddWindowFilter(thisConnection, [window windowNumber], compositingFilter, compositingType);
}

NB: It uses a private API

Answer 3

For those reading this in 2017 and using Swift 4 and wanting to change your BG Alpha you can add the following to your custom NSWindow class:

self.backgroundColor = NSColor.black
self.backgroundColor = NSColor.init(calibratedHue: 0, saturation: 0, brightness: 0, alpha: 0.2)

p.s. I do not need the blur effect yet and when I do, I'll update the answer