# convert(_:to:) Converts the rectangle from the receiver’s coordinate system to the specified layer’s coordinate system. ``` func convert(_ r: CGRect, to l: CALayer?) -> CGRect ``` ## Parameters `r` A point specifying a location in the coordinate system of `l`. `l` The layer into whose coordinate system `r` is to be converted. The receiver and `l` and must share a common parent layer. This parameter may be `nil`. ## Return Value The rectangle converted to the coordinate system of `l`. ## Discussion If you specify `nil` for the `l` parameter, this method returns the original rect with an origin added to the layer’s frame’s origin. The following example shows code that creates two layers, `redLayer` and `yellowLayer`. `yellowLayer` is scaled so that it is half of its original size. ```swift let layerFrame = CGRect(x: 0, y: 0, width: 640, height: 480) let redLayer = CALayer() redLayer.frame = layerFrame redLayer.backgroundColor = UIColor.red.cgColor let yellowLayer = CALayer() yellowLayer.frame = layerFrame yellowLayer.backgroundColor = UIColor.yellow.cgColor yellowLayer.transform = CATransform3DMakeScale(0.5, 0.5, 1) ``` The following figure shows the two layers and an overlaid rectangle with a frame of `(50, 50, 200, 200)` in the red layer’s coordinate system.  The following code shows how you can find the coordinates of that rectangle in the yellow layer’s coordinate system. ```swift let rect = CGRect(x: 50, y: 50, width: 200, height: 200) print(redLayer.convert(rect, to: yellowLayer)) // prints (-220.0, -140.0, 400.0, 400.0) ``` --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)