ios - 如何从UIImagePickerViewcontroller获取缩略图和原始图像？

Question

从相机中捕获照片后，我进行了图像压缩(400kb和1 Mb)，在iPhone 6中看起来将近3秒，而在iPhone 6s中则不到一秒。
有什么方法可以在不进行手动压缩的情况下获取缩略图和原始图像？

用于图像压缩的代码

UIImage的扩展

extension UIImage {
    // MARK: - UIImage+Resize
    func compressTo(_ expectedSizeInMb:Int) -> Data? {
        let sizeInBytes = expectedSizeInMb * 1024 * 1024
        var needCompress:Bool = true
        var imgData:Data?
        var compressingValue:CGFloat = 1.0
        while (needCompress && compressingValue > 0.0) {
            if let data:Data = jpegData(compressionQuality: compressingValue) {
                if data.count < sizeInBytes {
                    needCompress = false
                    imgData = data
                } else {
                    compressingValue -= 0.1
                }
            }
        }

        if let data = imgData {
            if (data.count < sizeInBytes) {
                return data
            }
        }
        return nil
    }
}

用法:

if let imageData = image.compressTo(1) {
print(imageData)
 }

Answer 1

对于保存在照片库中的图像:

尝试:

  let phAsset = info[UIImagePickerController.InfoKey.phAsset] as! PHAsset
  let options = PHImageRequestOptions()
  options.deliveryMode = .fastFormat
  options.isSynchronous = false

                         // you can change your target size to CGSize(width: Int , height:  Int) any number you want.
  PHImageManager.default().requestImage(for: phAsset, targetSize: PHImageManagerMaximumSize, contentMode: .default, options: options, resultHandler: { image , _ in

        let thumbnail = image
        // use your thumbnail
    })

对于从“相机”捕获的图像，您可以获取图像像素，而无需重新计算数据计数:

 let image = info[UIImagePickerController.InfoKey.originalImage] as! UIImage

        // pixels are the same on each device’s camera
    let widthPixels = image.size.width * image.scale
    let heightPixels = image.size.height * image.scale
    let sizeInBytes = 1024 * 1024

    var thumbnail : UIImage! = nil

    if Int(widthPixels * heightPixels) > sizeInBytes {
                 // assign custom width and height you need
         let rect = CGRect(x: 0.0, y: 0.0, width: 100, height: 100)
         UIGraphicsBeginImageContextWithOptions(rect.size, false, 1)
         let context = UIGraphicsGetCurrentContext()
         context?.interpolationQuality = .low
         image.draw(in: rect)
         let resizedImage = UIGraphicsGetImageFromCurrentImageContext()
         UIGraphicsEndImageContext()
         thumbnail = resizedImage

    } else {

        thumbnail = image

    }