使用圆角保存UIImage并使用Swift边框

Question

我正在使用imagePickerController从用户库中选择一张图片.我需要在应用程序中保存带圆角和边框的图片.保存图像时,它会保存未经改动的图像.我假设我只改变视图而不是图像本身.有没有办法将图片保存为视图中可以看到的内容？

@IBOutlet var imageViewer: UIImageView!

func imagePickerController(picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [NSObject : AnyObject]) {
    var imagePicked = info[UIImagePickerControllerOriginalImage] as UIImage
    imageViewer.layer.cornerRadius = 10.0
    imageViewer.clipsToBounds = true
    imageViewer.layer.frame = CGRectInset(imageViewer.layer.frame, 20, 20)
    imageViewer.layer.borderColor = UIColor.purpleColor().CGColor
    imageViewer.layer.borderWidth = 2.0
    imageViewer.image = imagePicked

谢谢您的帮助!

Answer 1

您需要执行的基本操作是:

• 剪切绘图区域以在没有角落的情况下绘制图像
• 画出图像
• 配置笔触颜色等

• 然后描绘用于剪裁的路径

  func imagePickerController(picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [NSObject : AnyObject]) {
    let borderWidth: CGFloat = 2.0
    let imagePicked = info[UIImagePickerControllerOriginalImage] as UIImage
  
    UIGraphicsBeginImageContextWithOptions(imageViewer.frame.size, false, 0)
  
    let path = UIBezierPath(roundedRect: CGRectInset(imageViewer.bounds, borderWidth / 2, borderWidth / 2), cornerRadius: 10.0)
    let context = UIGraphicsGetCurrentContext()
  
    CGContextSaveGState(context)
    // Clip the drawing area to the path
    path.addClip()
  
    // Draw the image into the context
    imagePicked.drawInRect(imageViewer.bounds)
    CGContextRestoreGState(context)
  
    // Configure the stroke
    UIColor.purpleColor().setStroke()
    path.lineWidth = borderWidth
  
    // Stroke the border
    path.stroke()
  
    roundedImage = UIGraphicsGetImageFromCurrentImageContext();
  
    UIGraphicsEndImageContext();
  
    view.addSubview(UIImageView(image: roundedImage))
  
    picker.dismissViewControllerAnimated(true, completion: nil)
  }
  

在上面的代码中,我将路径插入了笔划宽度的一半,因为笔划是沿着路径的中心绘制的,这意味着一个像素将最终在路径之外.

Answer 2

带边框的圆形 UIImage：

extension UIImage {
    
    func roundedWithStroke(width: CGFloat = 3) -> UIImage {
        let imageLayer = CALayer()
        let targetSize = CGSize(width: 29, height: 29)

        imageLayer.frame = CGRect(x: 0, y: 0, width: targetSize.width, height: targetSize.height)
        imageLayer.contents = cgImage
        imageLayer.masksToBounds = true
        imageLayer.cornerRadius = targetSize.width / 2
        imageLayer.borderWidth = width
        imageLayer.borderColor = UIColor.mainAccent.cgColor
        
        UIGraphicsBeginImageContextWithOptions(targetSize, false, scale)
        imageLayer.render(in: UIGraphicsGetCurrentContext()!)
        let roundedImage = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()
        
        return roundedImage ?? UIImage()
    }
    
}

您可以修改扩展方法以传递您需要的参数。