How to get this value as a CGFloat?

Question

I am asking for an Value like this:

[self.layer valueForKeyPath:@"transform.rotation.z"]

bit I need to pass it to a method which takes a CGFloat as parameter. What's the casting trick here?

Rhythmic Fistman · Accepted Answer · 2015-10-29T00:38:02.793

19

In Swift:

let f = view.layer.valueForKeyPath("transform.rotation.z")!.floatValue

In Objective-C:

NSNumber* n = [self.layer valueForKeyPath:@"transform.rotation.z"];
CGFloat f = [n floatValue];

edited Oct 29 '15 at 00:38

answered Jul 31 '09 at 15:24

Rhythmic Fistman

Wrong, `floatValue` is `float`, while `CGFloat` is `double` on 64-bit platforms. – wonder.mice Mar 29 '18 at 23:44
You’re re right! Here’s an answer that does it properly https://stackoverflow.com/a/34301580/22147 – Rhythmic Fistman Mar 30 '18 at 05:18
Or just `ifdef` on `CGFLOAT_IS_DOUBLE`. – wonder.mice Apr 01 '18 at 19:36

score 1 · Answer 2 · answered Aug 02 '09 at 05:56

1

If you wanted a more concise, one line way to do that, you can do:

CGFloat f = [[self.layer valueForKeyPath:@"transform.rotation.z"] floatValue];

answered Aug 02 '09 at 05:56

Neil

2 Answers2