Fix asset preview size

Tusker/Screens/Compose/Asset Picker/AssetCollectionViewController.swift

@@ -170,12 +170,22 @@ class AssetCollectionViewController: UICollectionViewController {
             return nil
         } else {
             let asset = fetchResult.object(at: indexPath.row - 1)
-            return UIContextMenuConfiguration(identifier: nil, previewProvider: { () -> UIViewController? in
+            return UIContextMenuConfiguration(identifier: indexPath as NSIndexPath, previewProvider: { () -> UIViewController? in
                 return AssetPreviewViewController(asset: asset)
             }, actionProvider: nil)
         }
     }
     
+    override func collectionView(_ collectionView: UICollectionView, previewForHighlightingContextMenuWithConfiguration configuration: UIContextMenuConfiguration) -> UITargetedPreview? {
+        if let indexPath = (configuration.identifier as? NSIndexPath) as IndexPath?, let cell = collectionView.cellForItem(at: indexPath) {
+            let parameters = UIPreviewParameters()
+            parameters.backgroundColor = .black
+            return UITargetedPreview(view: cell, parameters: parameters)
+        } else {
+            return nil
+        }
+    }
+    
     // MARK: - Interaction
     
     @objc func donePressed() {

Tusker/Screens/Compose/Asset Picker/AssetPreviewViewController.swift

@@ -63,6 +63,7 @@ class AssetPreviewViewController: UIViewController {
         PHImageManager.default().requestImage(for: asset, targetSize: view.bounds.size, contentMode: .aspectFit, options: options) { (image, _) in
             DispatchQueue.main.async {
                 imageView.image = image
+                self.preferredContentSize = image!.size
             }
         }
     }
@@ -90,6 +91,7 @@ class AssetPreviewViewController: UIViewController {
                     livePhotoView.topAnchor.constraint(equalTo: self.view.topAnchor),
                     livePhotoView.bottomAnchor.constraint(equalTo: self.view.bottomAnchor)
                 ])
+                self.preferredContentSize = livePhoto.size
             }
         }
     }
@@ -111,6 +113,7 @@ class AssetPreviewViewController: UIViewController {
                 player.play()
                 playerController.player = player
                 self.embedChild(playerController)
+                self.preferredContentSize = item.presentationSize
             }
         }
     }