Swift 从 UIView 层获取 UIImage

Question

我的 UIView 中有 CAShapeLayers，我想要视图中的 UIImage。
所以我正在尝试通过下面的函数，但在
处出现错误 UIGraphicsGetCurrentContext()

extension UIView
{
    func getImgFromVyuFnc() -> UIImage
    {
        UIGraphicsBeginImageContext(self.frame.size)

        self.layer.renderInContext(UIGraphicsGetCurrentContext())
        let image = UIGraphicsGetImageFromCurrentImageContext()

        UIGraphicsEndImageContext()
        return image!
    }
}

fatal error: unexpectedly found nil while unwrapping an Optional value 2017-08-17 04:17:47.230474 PicPac[1095:488887] fatal error: unexpectedly found nil while unwrapping an Optional value

Answer 1

如果传递给 UIGraphicsBeginImageContext(_) 的大小在一个或两个维度中为零，则 UIGraphicsGetCurrentContext() returns nil 等 UIGraphicsGetImageFromCurrentImageContext()。

Swift 从 UIView 层获取 UIImage

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