Why won't my NSColor extension see a CGColor?

Question

This baffles me... I'm trying to create a convenience initializer for NSColor which makes one out of a CGColor, but for some dang reason it just refuses to acknowledge that CGColor exists! I have imported Cocoa, and just for sanity I also imported CoreGraphics and even CoreGraphics.CGColor but still no luck!

Can anyone tell me what I'm doing wrong? Cleaning and rebuilding doesn't help...

Why? `NSColor` already has an [`init(cgColor:)`](https://developer.apple.com/library/mac/documentation/Cocoa/Reference/ApplicationKit/Classes/NSColor_Class/#//apple_ref/occ/clm/NSColor/colorWithCGColor:) — Hamish, Aug 04 '16 at 13:37
@Hamish aw, dang... that wasn't showing up in my autocomplete for some reason. :/ — Ky -, Aug 04 '16 at 13:41

Martin R · Accepted Answer · 2016-08-04T14:16:15.083

4

As already said in the comments, NSColor has an init(cgColor:) initializer, that might render your problem obsolete.

But since you are asking why it does not compile: The reason is that NSColor has a CGColor property, and that conflicts with the CGColor type. As a workaround, one can use the CGColorRef alias:

extension NSColor {

    convenience init(_ cgColor: CGColorRef) {
        // ...
    }
}

As Eric Aya said, the problem does not exist with Xcode 8 beta 4. The reason is that the NSColor property was renamed to cgColor, and does not conflict with the CGColor type anymore,

edited Aug 04 '16 at 14:16

answered Aug 04 '16 at 13:43

Martin R

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I've also noticed that OP's code works in Xcode 8 b4. Apple seems to have fixed this compiler issue. – Eric Aya Aug 04 '16 at 13:48
Beautiful! Thanks for all the knowledge! – Ky - Aug 04 '16 at 13:53
@EricAya: Yes, the property was renamed to `cgColor` in Swift 3. – Martin R Aug 04 '16 at 13:58

score 2 · Answer 2 · answered Aug 04 '16 at 13:34

2

Xcode is clearly misbehaving here. Workaround: use the complete type in the signature.

convenience init(_ cgColor: CoreGraphics.CGColor)

answered Aug 04 '16 at 13:34

Eric Aya

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Thanks for the swift answer! – Ky - Aug 04 '16 at 13:53
I think this solution is better than @MartinR's because it doesn't rely on the availability of a typealias, and thus is more general – Alexander Aug 04 '16 at 14:05
@AlexanderMomchliov: I do not disagree, but the main point of my answer was to explain *why* the problem occurs. It is not a "misbehaving compiler" but conflicting definitions in the frameworks. – Martin R Aug 04 '16 at 14:18
2

@MartinR To clarify, I like your answer more, because you give that backgorund explaination. However, I think EricAya's *solution* is better. – Alexander Aug 04 '16 at 14:24

Why won't my NSColor extension see a CGColor?

2 Answers2