Swift PNG图像以不正确的方向保存

Question

如果我在保存图像之前使用它是正常的.但如果我保存它并使用它以后是90度转动.我怎样才能确保它不会横向保存？

func saveEvent(_ center1: CLLocation, title2: String, imagePicked1: UIImage)
    {
        let data = UIImagePNGRepresentation(imagePicked1);///
        let url = NSURL(fileURLWithPath: NSTemporaryDirectory()).appendingPathComponent(NSUUID().uuidString+".dat")
        do {
            try data!.write(to: url!, options: [])
        } catch let e as NSError {
            print("Error! \(e)");
            return
        }
        let image11 = CKAsset(fileURL: url!)

        self.eventRecord.setObject(image11 as CKAsset, forKey: "Picture")
        let publicData = CKContainer.default().publicCloudDatabase
            publicData.save(self.eventRecord, completionHandler: { record, error in
                if error == nil
                {
                    print("Image saved")
                }else{
                    print(error!)
                }
        })
    }

Answer 1

如果您需要以正确的旋转方式保存PNG,则需要重新绘制图像(如果图像的方向不是这样).up.您可以重新绘制如下:

extension UIImage {
    var png: Data? {
        guard let flattened = flattened else { return nil }
        return flattened.pngData()  // Swift 4.2 or later
        // return UIImagePNGRepresentation(flattened)  // Swift 4.1  or earlier
    }
    var flattened: UIImage? {
        if imageOrientation == .up { return self }
        UIGraphicsBeginImageContextWithOptions(size, false, scale)
        defer { UIGraphicsEndImageContext() }
        draw(in: CGRect(origin: .zero, size: size))
        return UIGraphicsGetImageFromCurrentImageContext()
    }
}

编辑/更新:

对于iOS10 + tvOS10 +,您可以使用UIGraphicsImageRenderer:

extension UIImage {
    var png: Data? {
        return flattened.pngData()
    }
    var flattened: UIImage {
        if imageOrientation == .up { return self }
        return UIGraphicsImageRenderer(size: size, format: imageRendererFormat).image { _ in draw(at: .zero) }
    }
}

let image = UIImage(data: try! Data(contentsOf: URL(string: "https://i.stack.imgur.com/varL9.jpg")!))!
if let data = image.png {
    let imageFromPNGData = UIImage(data: data)
}