# init(radialSpace:start:startRadius:end:endRadius:function:extendStart:extendEnd:) Creates a shading object to use for radial shading. ``` init?(radialSpace space: CGColorSpace, start: CGPoint, startRadius: CGFloat, end: CGPoint, endRadius: CGFloat, function: CGFunction, extendStart: Bool, extendEnd: Bool) ``` ## Parameters `space` The color space in which color values are expressed. Core Graphics retains this object; upon return, you may safely release it. `start` The center of the starting circle, in the shading’s target coordinate space. `startRadius` The radius of the starting circle, in the shading’s target coordinate space. `end` The center of the ending circle, in the shading’s target coordinate space. `endRadius` The radius of the ending circle, in the shading’s target coordinate space. `function` A CGFunction object created by the function [`init(info:domainDimension:domain:rangeDimension:range:callbacks:)`](/documentation/CoreGraphics/CGFunction/init(info:domainDimension:domain:rangeDimension:range:callbacks:)). This object refers to your function for creating a radial shading. Core Graphics retains this object; upon return, you may safely release it. `extendStart` A Boolean value that specifies whether to extend the shading beyond the starting circle. `extendEnd` A Boolean value that specifies whether to extend the shading beyond the ending circle. ## Return Value A new Core Graphics radial shading. In Objective-C, you’re responsible for releasing this object using [`CGShadingRelease`](/documentation/CoreGraphics/CGShadingRelease). ## Discussion A radial shading is a color blend that varies between two circles. To draw the shading, call the function [`drawShading(_:)`](/documentation/CoreGraphics/CGContext/drawShading(_:)). --- 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)