iOS 13 UITextView 将 UITextView 转换为图像无法正常工作。在 iOS 12 以下运行良好

Question

如何在 iOS 13 中解决此问题？我正在截取 UITextView 内容大小的屏幕截图。直到 iOS 12 一切正常。但 iOS 13 以后的问题是，它无法截取正在剪切的完整屏幕截图。下面是 iOS 12 以下和 iOS 13 之后的输出图片。 Less than iOS 12

下面是我用来截取 UITextView 屏幕截图的代码:

let textView = UITextView()
UIGraphicsBeginImageContextWithOptions(textView.contentSize, textView.isOpaque, 0.0)
let savedContentOffset: CGPoint = textView.contentOffset
let savedFrame: CGRect = textView.frame
textView.frame = CGRect(x: 0, y: 0, width: textView.contentSize.width, height: textView.contentSize.height)
textView.layer.render(in: UIGraphicsGetCurrentContext()!)
let image = UIGraphicsGetImageFromCurrentImageContext()
textView.contentOffset = savedContentOffset
textView.frame = savedFrame
UIGraphicsEndImageContext()

我找到了这个问题的解决方案下边是更新的工作代码

选项 1:-下面的代码使用 UILabel

let SCREEN_WIDTH = UIScreen.main.bounds.size.width
let SCREEN_HEIGHT = UIScreen.main.bounds.size.height
func buttonAction() {
    let textView = UITextView()
    textView.frame = CGRect(x: 10, y: 50, width: SCREEN_WIDTH - 20, height: SCREEN_HEIGHT * 2)
    let lab = UILabel(frame: CGRect(x: 0, y: 0, width: SCREEN_WIDTH - 20, height: textView.contentSize.height))
    lab.backgroundColor = UIColor.white
    lab.font = textView.font
    lab.textColor = UIColor.black
    lab.numberOfLines = 0
    lab.text = textView.text
    textView.addSubview(lab)

    UIGraphicsBeginImageContextWithOptions(CGSize(width: SCREEN_WIDTH - 20, height: textView.contentSize.height), _: true, _: 1)
    if let context = UIGraphicsGetCurrentContext() {
        lab.layer.render(in: context)
    }
    let image = UIGraphicsGetImageFromCurrentImageContext()
    UIGraphicsEndImageContext()
    textView.frame = CGRect(x: 10, y: 50, width: SCREEN_WIDTH - 20, height: SCREEN_HEIGHT * 2)
    lab.removeFromSuperview()

}

选项 2:-下面的代码使用 TempView

let SCREEN_WIDTH = UIScreen.main.bounds.size.width
let SCREEN_HEIGHT = UIScreen.main.bounds.size.height

func buttonAction() {
   let textView = UITextView()
   textView.frame = CGRect(x: 10, y: 50, width: SCREEN_WIDTH - 20, height: SCREEN_HEIGHT * 2)
UIGraphicsBeginImageContextWithOptions(CGSize(width: SCREEN_WIDTH - 20, height: textView.contentSize.height), _: true, _: 1)
if #available(iOS 13, *) {
    // iOS 13 (or newer)
    let tempView = UIView(frame: CGRect(x: 0, y: 0, width: textView.contentSize.width, height: textView.contentSize.height))
    tempView.addSubview(textView)
    if let context = UIGraphicsGetCurrentContext() {
        tempView.layer.render(in: context)
    }
    tempView.removeFromSuperview()
    view.addSubview(textView)
} else {
    // iOS 12 or older
    if let context = UIGraphicsGetCurrentContext() {
        textView.layer.render(in: context)
    }
}

选项 3:-尝试使用第三方库我已经使用过YYTextView https://github.com/ibireme/YYText

Answer 1

不要绘制图层，而是使用 attributeText

let size = self.textView.contentSize
UIGraphicsBeginImageContextWithOptions(size, self.textView.isOpaque, 0)
//the textView has 8 margin
textView.attributedText.draw(in: CGRect.init(x: 0, y: 0, width: size.width - 16, height: size.height))
let image = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()