NSWindow with round corners and shadow

Question

I'm trying to crate a NSWindow without title bar (NSBorderlessWindowMask) with round corners and a shadow, similar to the below "Welcome to Xcode" window.

I make a subclass of NSWindow:

@implementation FlatWindow

- (id)initWithContentRect:(NSRect)contentRect styleMask:(NSUInteger)aStyle backing:(NSBackingStoreType)bufferingType defer:(BOOL)flag
{
    self = [super initWithContentRect:contentRect styleMask:NSBorderlessWindowMask backing:bufferingType defer:flag];

    if ( self )
    {
        [self setOpaque:NO];
        [self setBackgroundColor:[NSColor clearColor]];
        [self setMovableByWindowBackground:TRUE];
        [self setStyleMask:NSBorderlessWindowMask];
        [self setHasShadow:YES];
    }

    return self;
}

- (void) setContentView:(NSView *)aView
{
    aView.wantsLayer            = YES;
    aView.layer.frame           = aView.frame;
    aView.layer.cornerRadius    = 10.0;
    aView.layer.masksToBounds   = YES;

    [super setContentView:aView];
}

@end

And a subclass of NSView:

@implementation ColoredView

- (void)drawRect:(NSRect)dirtyRect {
    [super drawRect:dirtyRect];

    [[NSColor windowBackgroundColor] set];
    NSRectFill(dirtyRect);
}

@end

This gives me a window without title bar with round corners, but the default shadow on NSWindow is gone. How can I add the default shadow to this window?

EDIT1:

NSWindow with NSShadow. This shadow is not shown.

@implementation FlatWindow

- (id)initWithContentRect:(NSRect)contentRect styleMask:(NSUInteger)aStyle backing:(NSBackingStoreType)bufferingType defer:(BOOL)flag
{
    self = [super initWithContentRect:contentRect styleMask:NSBorderlessWindowMask backing:bufferingType defer:flag];

    if ( self )
    {
        [self setOpaque:NO];
        [self setBackgroundColor:[NSColor clearColor]];
        [self setMovableByWindowBackground:TRUE];
        [self setStyleMask:NSBorderlessWindowMask];
        [self setHasShadow:YES];
    }

    return self;
}

- (void) setContentView:(NSView *)aView
{
    aView.wantsLayer            = YES;
    aView.layer.frame           = aView.frame;
    aView.layer.cornerRadius    = 10.0;
    aView.layer.masksToBounds   = YES;

    NSShadow *dropShadow = [[NSShadow alloc] init];
    [dropShadow setShadowColor:[NSColor blackColor]];
    [dropShadow setShadowBlurRadius:10.0];
    [aView setShadow: dropShadow];

    [super setContentView:aView];
}

@end

Answer 1

Update

I realised old approach was not able to create precise round corner. So I updated example to make precise round corner.

        window1.backgroundColor             =   NSColor.whiteColor()
        window1.opaque                      =   false
        window1.styleMask                   =   NSResizableWindowMask
                                            |   NSTitledWindowMask
                                            |   NSFullSizeContentViewWindowMask
        window1.movableByWindowBackground   =   true
        window1.titlebarAppearsTransparent  =   true
        window1.titleVisibility             =   .Hidden
        window1.showsToolbarButton          =   false
        window1.standardWindowButton(NSWindowButton.FullScreenButton)?.hidden   =   true
        window1.standardWindowButton(NSWindowButton.MiniaturizeButton)?.hidden  =   true
        window1.standardWindowButton(NSWindowButton.CloseButton)?.hidden        =   true
        window1.standardWindowButton(NSWindowButton.ZoomButton)?.hidden         =   true

        window1.setFrame(CGRect(x: 400, y: 0, width: 400, height: 500), display: true)
        window1.makeKeyAndOrderFront(self)

Here's full working example.

---

Oudated

Special treatment is not required at least in OS X 10.10.

import Cocoa

class ExampleApplicationController: NSObject, NSApplicationDelegate {
    class ExampleController {

        let window1 =   NSWindow()
        let view1   =   NSView()

        init(){
            window1.setFrame(CGRect(x: 400, y: 0, width: 400, height: 500), display: true)
            window1.contentView                 =   view1

            window1.backgroundColor             =   NSColor.clearColor()
            window1.opaque                      =   false
            window1.styleMask                   =   NSBorderlessWindowMask | NSResizableWindowMask
            window1.movableByWindowBackground   =   true
            window1.makeKeyAndOrderFront(self)

            view1.wantsLayer                =   true
            view1.layer!.cornerRadius       =   10
            view1.layer!.backgroundColor    =   NSColor.whiteColor().CGColor

            /// :ref:   http://stackoverflow.com/questions/19940019/nswindow-with-round-corners-and-shadow/27613308#21247949
            window1.invalidateShadow()  //  This manual invalidation is REQUIRED because shadow generation is an expensive operation.
        }
    }

    let example1    =   ExampleController()
}

You can download a working example from here.