init(radialSpace:start:startRadius:end:endRadius:function:extendStart:extendEnd:)
Creates a shading object to use for radial shading.
Declaration
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:). 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.
Discussion
A radial shading is a color blend that varies between two circles. To draw the shading, call the function drawShading(_:).