Graphics Reference
In-Depth Information
[shipLayer
addAnimation
:animation
forKey
:
nil
];
}
Figure 8.2
The spaceship layer rotating to match the tangent of the curve
Virtual Properties
We mentioned earlier that the fact that property animations work on key
paths
instead of
keys means that we can animate subproperties
and even virtual properties
. But what is a
virtual
property?
Consider a rotation animation: If we wanted to animate a rotating object, we'd have to
animate the
transform
because there is no explicit angle/orientation property on a
CALayer
. We might do that as shown in Listing 8.8.
Listing 8.8
Rotating a Layer by Animating the
transform
Property
@interface
ViewController ()
@property
(
nonatomic
,
weak
)
IBOutlet
UIView
*containerView;
@end
@implementation
ViewController
