Resolve image metadata

Sources/Gallery/Images/Image.swift

@@ -13,14 +13,43 @@ public class Image: Equatable {
   }
 }
 
+// MARK: - UIImage with metadata typealias
+public typealias UIImageData = (image: UIImage, metadata: CGImageMetadata)
+
 // MARK: - UIImage
 
 extension Image {
 
-  /// Resolve UIImage synchronously
-  ///
-  /// - Parameter size: The target size
-  /// - Returns: The resolved UIImage, otherwise nil
+  /// Resolve UIImage and it's metadata asynchronously
+  /// - Parameters:
+  ///   -  completion: A block to be called when the process is complete. The block takes the resolved UIImage and its CGImageMetadata
+  ///    as parameters.
+  public func resolveImageData(completion: @escaping (UIImageData) -> Void) {
+    let options = PHImageRequestOptions()
+    options.isNetworkAccessAllowed = true
+    options.deliveryMode = .highQualityFormat
+    PHImageManager.default().requestImageData(for: asset, options: options) { imageData, dataUTI, _, _ in
+      let destData = NSMutableData() as CFMutableData
+      guard let imageData = imageData,
+            let dataUTI = dataUTI,
+            let imageSource = CGImageSourceCreateWithData(imageData as CFData, nil),
+            let imageDestination = CGImageDestinationCreateWithData(destData, dataUTI as CFString, 1, nil),
+            let imageRef = CGImageSourceCreateImageAtIndex(imageSource, 0, nil) else {
+        return
+      }
+      CGImageDestinationAddImage(imageDestination, imageRef, nil)
+      CGImageDestinationFinalize(imageDestination)
+      guard let imageMetadata = CGImageSourceCopyMetadataAtIndex(imageSource, 0, nil),
+            let image = UIImage(data: destData as Data) else {
+        return
+      }
+      completion(UIImageData(image, imageMetadata))
+    }
+  }
+
+  /// Resolve UIImage asynchronously
+  /// - Parameters:
+  ///   - completion: A block to be called when image resolving is complete. The block takes the resolved UIImage as a parameter.
   public func resolve(completion: @escaping (UIImage?) -> Void) {
     let options = PHImageRequestOptions()
     options.isNetworkAccessAllowed = true
@@ -31,16 +60,40 @@ extension Image {
       targetSize: PHImageManagerMaximumSize,
       contentMode: .default,
       options: options) { (image, _) in
-        completion(image)
+      completion(image)
     }
   }
 
-  /// Resolve an array of Image
-  ///
+  /// Resolve an array of Images and their metadata
+  /// - Parameters:
+  ///   - images: The array of Images
+  ///   -  completion: A block to be called when the process is complete. The block takes the array of resolved UIImages and their
+  ///    CGImageMetadata as parameters.
+  public static func resolveImageData(images: [Image], completion: @escaping ([UIImageData]) -> Void) {
+    let dispatchGroup = DispatchGroup()
+    var convertedImages = [Int: UIImageData]()
+
+    for (index, image) in images.enumerated() {
+      dispatchGroup.enter()
+
+      image.resolveImageData(completion: { resolvedImage, metadata in
+        convertedImages[index] = (resolvedImage, metadata)
+        dispatchGroup.leave()
+      })
+    }
+
+    dispatchGroup.notify(queue: .main, execute: {
+      let sortedImages = convertedImages
+        .sorted(by: { $0.key < $1.key })
+        .map({ $0.value })
+      completion(sortedImages)
+    })
+  }
+
+  /// Resolve an array of Images
   /// - Parameters:
-  ///   - images: The array of Image
-  ///   - size: The target size for all images
-  ///   - completion: Called when operations completion
+  ///   - images: The array of Images
+  ///   - completion: A block to be called when the process is complete. The block takes the array of resolved UIImages as a parameter.
   public static func resolve(images: [Image], completion: @escaping ([UIImage?]) -> Void) {
     let dispatchGroup = DispatchGroup()
     var convertedImages = [Int: UIImage]()