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

Question

開始的iOS 10，蘋果文檔這類功能的UIKit：

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

不過，我是不是能夠訪問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

功能準備的定義在UIGraphicsRendererSubclass 您可以通過調用import UIKit.UIGraphicsRendererSubclass