Adding a Shadow to a NSImageView

Question

I have a NSImageView and want to add a shadow. I've tried doing it programmatically with:

NSShadow *shadow = [[[NSShadow alloc] init] autorelease];
[shadow setShadowBlurRadius:4.0f];
[shadow setShadowOffset:CGSizeMake(4.0f, 4.0f)];
[shadow setShadowColor:[NSColor blackColor]];

[view setShadow:shadow];

But it won't appear. Any ideas? Thanks.

You could try creating an empty NSImage (of the same size as the one you want to draw), `lockFocus` on it, set the shadow, and draw the original into the new one (and `unlockFocus`). I use that technique for tinting images; can't guarantee it'll work for shadow. — Richard, Jan 24 '11 at 21:13

score 10 · Accepted Answer · answered Jan 24 '11 at 20:43

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You have to set the parameters of the shadow. By default, it's all zeroes, so it has no visible effect on a view.

See -setShadowColor:, -setShadowRadius:, and -setShadowOffset: on NSShadow, I believe.

answered Jan 24 '11 at 20:43

Jonathan Grynspan

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I tried adding all the above to no effect. I updated the above sample. – Kevin Sylvestre Jan 24 '11 at 20:57
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Is your view also backed by a `CALayer`? If not, you must enable Core Animation backing by sending `setWantsLayer:` (with a value of `YES`) to your view before setting the shadow. – Jonathan Grynspan Jan 24 '11 at 21:16
@Jonathan: that was what I was about to post as an answer indeed. `setShadow:` simply copies the shadow's properties to the Core Animation layer, so the view must be backed by a `CALayer`. This is also noticeable when you want to apply a shadow to a view using Interface Builder. – Joost Jan 24 '11 at 21:21
Ayup. Have had my head in iOS for a while, so it briefly slipped my mind that on the Mac, views are not layer-backed by default. :) – Jonathan Grynspan Jan 24 '11 at 21:32
Any way to avoid clipping the shadow if once a CALayer is enabled? – Kevin Sylvestre Jan 24 '11 at 22:29
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I believe if the superview is also layer-backed, the clipping rules change, but it has been a while. – Jonathan Grynspan Jan 24 '11 at 22:54
Not to sound crass, but to award a bounty, you must actively click the appropriate button in your UI. (Okay, that sounded crass anyway, didn't it?) – Jonathan Grynspan Jan 25 '11 at 02:33
@Jonathan Sorry! I tried to add it when I marked an answer but it required waiting a day (and then I forgot). My apologies! – Kevin Sylvestre Jan 28 '11 at 22:20
No worries. I just didn't want that precious precious rep to go to waste. Precious, delicious rep... – Jonathan Grynspan Jan 29 '11 at 00:08

score 2 · Answer 2 · answered Nov 30 '18 at 12:23

2

Swift 4

let shadow = NSShadow()
shadow.shadowOffset = NSMakeSize(2, -2)
shadow.shadowColor = NSColor.lightGray
shadow.shadowBlurRadius = 3

imageView.wantsLayer = true
imageView.shadow = shadow

answered Nov 30 '18 at 12:23

Confused Vorlon

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Adding a Shadow to a NSImageView

2 Answers2

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