MediaPickerPreview.diff

diff --git a/Pod/Classes/WPFullScreenAssetPreviewViewController.m b/Pod/Classes/WPFullScreenAssetPreviewViewController.m
index 3765e0c..8ad225d 100644
--- a/Pod/Classes/WPFullScreenAssetPreviewViewController.m
+++ b/Pod/Classes/WPFullScreenAssetPreviewViewController.m
@@ -143,4 +143,9 @@ - (void)handleTapOnAsset:(UIGestureRecognizer *)gestureRecognizer
     }
 }
 
+- (CGSize)preferredContentSize
+{
+    return [self.asset pixelSize];
+}
+
 @end
diff --git a/Pod/Classes/WPMediaCollectionDataSource.h b/Pod/Classes/WPMediaCollectionDataSource.h
index 4d14793..1667480 100644
--- a/Pod/Classes/WPMediaCollectionDataSource.h
+++ b/Pod/Classes/WPMediaCollectionDataSource.h
@@ -137,6 +137,13 @@ typedef int32_t WPMediaRequestID;
  */
 - (NSDate *)date;
 
+/**
+ *  The size, in pixels, of the asset’s image or video data.
+ *
+ *  @return The size, in pixels, of the asset’s image or video data.
+ */
+- (CGSize)pixelSize;
+
 @end
 
 /**
diff --git a/Pod/Classes/WPMediaCollectionViewController.m b/Pod/Classes/WPMediaCollectionViewController.m
index 0414926..eb52b45 100644
--- a/Pod/Classes/WPMediaCollectionViewController.m
+++ b/Pod/Classes/WPMediaCollectionViewController.m
@@ -14,7 +14,8 @@ @interface WPMediaCollectionViewController ()
  UINavigationControllerDelegate,
  WPMediaGroupPickerViewControllerDelegate,
  UIPopoverPresentationControllerDelegate,
- UICollectionViewDelegateFlowLayout
+ UICollectionViewDelegateFlowLayout,
+ UIViewControllerPreviewingDelegate
 >
 
 @property (nonatomic, strong) UICollectionViewFlowLayout *layout;
@@ -107,7 +108,13 @@ - (void)viewDidLoad
 
         });
     }];
-    [self.view addGestureRecognizer:self.longPressGestureRecognizer];
+
+    if ([self.traitCollection containsTraitsInCollection:[UITraitCollection traitCollectionWithForceTouchCapability:UIForceTouchCapabilityAvailable]]) {
+        [self registerForPreviewingWithDelegate:self sourceView:self.view];
+    } else {
+        [self.view addGestureRecognizer:self.longPressGestureRecognizer];
+    }
+
     [self refreshData];
 }
 
@@ -737,19 +744,50 @@ - (void)mediaGroupPickerViewControllerDidCancel:(WPMediaGroupPickerViewControlle
 
 - (void)handleLongPressOnAsset:(UIGestureRecognizer *)gestureRecognizer {
     if (gestureRecognizer.state == UIGestureRecognizerStateBegan) {
-        WPFullScreenAssetPreviewViewController *fullScreenImageVC = [[WPFullScreenAssetPreviewViewController alloc] init];
-        CGPoint pointTouched = [gestureRecognizer locationInView:self.collectionView];
-        NSIndexPath *indexPath = [self.collectionView indexPathForItemAtPoint:pointTouched];
-        if (!indexPath) {
-            return;
-        }
-        id<WPMediaAsset> asset = [self assetForPosition:indexPath];
-        if (!asset) {
-            return;
+        CGPoint location = [gestureRecognizer locationInView:self.collectionView];
+        UIViewController *viewController = [self fullscreenAssetPreviewControllerForTouchLocation:location];
+
+        if (viewController) {
+            [self.navigationController pushViewController:viewController animated:YES];
         }
-        fullScreenImageVC.asset = asset;
-        [self.navigationController pushViewController:fullScreenImageVC animated:YES];
     }
 }
 
+- (nullable WPFullScreenAssetPreviewViewController *)fullscreenAssetPreviewControllerForTouchLocation:(CGPoint)location
+{
+    NSIndexPath *indexPath = [self.collectionView indexPathForItemAtPoint:location];
+    if (!indexPath) {
+        return nil;
+    }
+
+    id<WPMediaAsset> asset = [self assetForPosition:indexPath];
+    if (!asset) {
+        return nil;
+    }
+
+    WPFullScreenAssetPreviewViewController *fullScreenImageVC = [[WPFullScreenAssetPreviewViewController alloc] init];
+    fullScreenImageVC.asset = asset;
+    return fullScreenImageVC;
+}
+
+#pragma mark - UIViewControllerPreviewingDelegate
+
+- (nullable UIViewController *)previewingContext:(id <UIViewControllerPreviewing>)previewingContext viewControllerForLocation:(CGPoint)location
+{
+    CGPoint convertedLocation = [self.collectionView convertPoint:location fromView:self.view];
+    NSIndexPath *indexPath = [self.collectionView indexPathForItemAtPoint:convertedLocation];
+    if (indexPath) {
+        UICollectionViewLayoutAttributes *attributes = [self.collectionView layoutAttributesForItemAtIndexPath:indexPath];
+        CGRect rect = [self.view convertRect:attributes.frame fromView:self.collectionView];
+        [previewingContext setSourceRect:rect];
+    }
+
+    return [self fullscreenAssetPreviewControllerForTouchLocation:convertedLocation];
+}
+
+- (void)previewingContext:(id <UIViewControllerPreviewing>)previewingContext commitViewController:(UIViewController *)viewControllerToCommit
+{
+    [self.navigationController pushViewController:viewControllerToCommit animated:YES];
+}
+
 @end
diff --git a/Pod/Classes/WPPHAssetDataSource.m b/Pod/Classes/WPPHAssetDataSource.m
index 6625f21..5b079d6 100644
--- a/Pod/Classes/WPPHAssetDataSource.m
+++ b/Pod/Classes/WPPHAssetDataSource.m
@@ -462,6 +462,11 @@ - (NSDate *)date
     return [self creationDate];
 }
 
+- (CGSize)pixelSize
+{
+    return CGSizeMake((CGFloat)self.pixelWidth, (CGFloat)self.pixelHeight);
+}
+
 @end
 
 #pragma mark - WPPHAssetCollection