swift UIGraphicsGetImageFromCurrentImageContext can't release memory

Question

Swift Code

When we get a screenshot of a UIView, we use this code usually:

UIGraphicsBeginImageContextWithOptions(frame.size, false, scale)
drawViewHie         


        

Answer 1

I solved this problem by putting image operations in another queue!

private func processImage(image: UIImage, size: CGSize, completion: (image: UIImage) -> Void) {
    dispatch_async(dispatch_get_global_queue(Int(QOS_CLASS_USER_INITIATED.rawValue), 0)) {
        UIGraphicsBeginImageContextWithOptions(size, true, 0)
        image.drawInRect(CGRect(origin: CGPoint.zero, size: size))
        let tempImage = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()

        completion(image: tempImage)
    }
}

Answer 2

private extension UIImage
{
    func resized() -> UIImage {
        let height: CGFloat = 800.0
        let ratio = self.size.width / self.size.height
        let width = height * ratio

        let newSize = CGSize(width: width, height: height)
        let newRectangle = CGRect(x: 0, y: 0, width: width, height: height)

        UIGraphicsBeginImageContext(newSize)
        self.draw(in: newRectangle)

        let resizedImage = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()

        return resizedImage!
    } 
}