Graphics Reference
In-Depth Information
//create sublayer
CALayer
*blueLayer = [
CALayer
layer
];
blueLayer.
frame
=
CGRectMake
(
50.0f
,
50.0f
,
100.0f
,
100.0f
);
blueLayer.backgroundColor = [UIColor
blueColor
].CGColor;
//set controller as layer delegate
blueLayer.delegate =
self
;
//ensure that layer backing image uses correct scale
blueLayer.contentsScale = [UIScreen
mainScreen
].scale;
//add layer to our view
[
self
.
layerView
.layer
addSublayer
:blueLayer];
//force layer to redraw
[blueLayer
display
];
}
- (
void
)drawLayer:(
CALayer
*)layer inContext:(
CGContextRef
)ctx
{
//draw a thick red circle
CGContextSetLineWidth
(ctx,
10.0f
);
CGContextSetStrokeColorWithColor
(ctx, [
UIColor
redColor
].
CGColor
);
CGContextStrokeEllipseInRect
(ctx, layer.
bounds
);
}
@end
