Re: CALayer defaultValueForKey
Re: CALayer defaultValueForKey
- Subject: Re: CALayer defaultValueForKey
- From: Scott Anguish <email@hidden>
- Date: Tue, 17 Feb 2009 14:59:09 -0500
On 15-Feb-09, at 6:07 PM, Gordon Apple wrote:
The docs are a clear a mud on this. What do you get from CALayer's
defaultValueForKey? Is this the same as one would expect from
valueForKey
for an NSDictionary? The return type is "id".
" If this method returns nil a suitable “zero” default value for the
property is provided, based on the declared type of the key. For
example, if
key is a CGSize object, a size of (0.0,0.0) is returned. For a
CGRect an
empty rectangle is returned. For CGAffineTransform and
CATransform3D, the
appropriate identity matrix is returned."
What does that mean? If you want a CGSize, does that mean you
have to
use "sizeValue" on what is returned and convert it? Or
"CGSizeValue"? But
wait, that's an iPhone SDK extension. Why isn't that in Cocoa?
Read the Core animation Programming Guide section on key-value coding
extensions, it describes the wrapping for defaultValueForKey: and
other similar methods.
also, there is an additional addendum like chapter that explains the
default values for all the properties.
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