Graphics Reference
In-Depth Information
transform =
CATransform3DTranslate
(transform,
0
, -
200
,
0
);
replicator.
instanceTransform
= transform;
//apply a color shift for each instance
replicator.
instanceBlueOffset
= -
0.1
;
replicator.
instanceGreenOffset
= -
0.1
;
//create a sublayer and place it inside the replicator
CALayer
*layer = [
CALayer
layer
];
layer.
frame
=
CGRectMake
(
100.0f
,
100.0f
,
100.0f
,
100.0f
);
layer.
backgroundColor
= [
UIColor
whiteColor
].
CGColor
;
[replicator
addSublayer
:layer];
}
@end
Figure 6.8
A ring of layers, created using
CAReplicatorLayer
Note how the color of the layers changes as they are repeated: This was achieved using the
instanceBlueOffset
and
instanceGreenOffset
properties. By decreasing the
intensity of the blue and green color components for each repetition, we've caused the
layers to color-shift toward red.
This replication effect may look cool, but what are the practical applications?
CAReplicatorLayer
is useful for special effects such as drawing a contrail behind a
missile in a game, or a particle explosion (although iOS 5 introduced
CAEmitterLayer
,