Layer Performance - iOS Core Animation - page 325

@property ( nonatomic , strong ) IBOutlet UIScrollView *scrollView;
@end
@implementation ViewController
- ( void )viewDidLoad
{
[ super viewDidLoad ];
//set content size
self . scrollView . contentSize = CGSizeMake (( WIDTH - 1 )* SPACING ,
( HEIGHT - 1 )* SPACING );
//set up perspective transform
CATransform3D transform = CATransform3DIdentity ;
transform. m34 = - 1.0 / CAMERA_DISTANCE ;
self . scrollView . layer . sublayerTransform = transform;
//create layers
for ( int z = DEPTH - 1 ; z >= 0 ; z--)
{
for ( int y = 0 ; y < HEIGHT ; y++)
{
for ( int x = 0 ; x < WIDTH ; x++)
{
//create layer
CALayer *layer = [ CALayer layer ];
layer. frame = CGRectMake ( 0 , 0 , SIZE , SIZE );
layer. position = CGPointMake (x* SPACING , y* SPACING );
layer. zPosition = -z* SPACING ;
//set background color
layer. backgroundColor =
[ UIColor colorWithWhite : 1 -z*( 1.0 / DEPTH ) alpha : 1 ]. CGColor ;
//attach to scroll view
[ self . scrollView . layer addSublayer :layer];
}
}
}