如何使用`prepare（_ context：CGContext，with rendererContext：UIGraphicsRendererContext）`？

Question

开始的iOS 10，苹果文档这类功能的UIKit：

class func prepare(_ context: CGContext, with rendererContext: UIGraphicsRendererContext)

不过，我是不是能够访问prepare在Xcode 8.3.3：

// error: Type 'UIGraphicsRenderer' has no member 'prepare' 
UIGraphicsRenderer.prepare(UIGraphicsGetCurrentContext()!, with: UIGraphicsRendererContext()) 

// error: Type 'UIGraphicsImageRenderer' has no member 'prepare' 
UIGraphicsImageRenderer.prepare(UIGraphicsGetCurrentContext()!, with: UIGraphicsRendererContext()) 

Answer 1

功能准备的定义在UIGraphicsRendererSubclass 您可以通过调用import UIKit.UIGraphicsRendererSubclass