delegate method to customize title text

Pod/Classes/ios/NYTPhotosViewController.h

@@ -148,6 +148,17 @@ extern NSString * const NYTPhotosViewControllerDidDismissNotification;
  */
 - (UIView * _Nullable)photosViewController:(NYTPhotosViewController *)photosViewController captionViewForPhoto:(id <NYTPhoto>)photo;
 
+/**
+ *  Returns a string to display as the title of a photo.
+ *
+ *  @param photosViewController The `NYTPhotosViewController` instance that sent the delegate message.
+ *  @param photo                The photo object over which to display the title.
+ *  @param photoIndex           The index of the photo.
+ *
+ *  @return The text to display as the title for the corresponding photo. Return `nil` to show a default title of the current photo index and the total number of photos.
+ */
+- (NSString * _Nullable)photosViewController:(NYTPhotosViewController *)photosViewController titleForPhoto:(id <NYTPhoto>)photo atIndex:(NSUInteger)photoIndex;
+
 /**
  *  Returns a view to display while a photo is loading. Can be any `UIView` object, but is expected to respond to `sizeToFit` appropriately. This view will be sized and centered in the blank area, and hidden when the photo image is loaded.
  *

Pod/Classes/ios/NYTPhotosViewController.m

@@ -215,17 +215,25 @@ - (void)addOverlayView {
     [self setOverlayViewHidden:YES animated:NO];
 }
 
+
 - (void)updateOverlayInformation {
-    NSUInteger displayIndex = 1;
+    NSString *overlayTitle;
 
     NSUInteger photoIndex = [self.dataSource indexOfPhoto:self.currentlyDisplayedPhoto];
-    if (photoIndex < self.dataSource.numberOfPhotos) {
-        displayIndex = photoIndex + 1;
+
+    if ([self.delegate respondsToSelector:@selector(photosViewController:titleForPhoto:atIndex:)]) {
+        overlayTitle = [self.delegate photosViewController:self titleForPhoto:self.currentlyDisplayedPhoto atIndex:photoIndex];
     }
 
-    NSString *overlayTitle;
-    if (self.dataSource.numberOfPhotos > 1) {
-        overlayTitle = [NSString localizedStringWithFormat:NSLocalizedString(@"%lu of %lu", nil), (unsigned long)displayIndex, (unsigned long)self.dataSource.numberOfPhotos];
+    if (!overlayTitle) {
+        NSUInteger displayIndex = 1;
+
+        if (photoIndex < self.dataSource.numberOfPhotos) {
+            displayIndex = photoIndex + 1;
+        }
+        if (self.dataSource.numberOfPhotos > 1) {
+            overlayTitle = [NSString localizedStringWithFormat:NSLocalizedString(@"%lu of %lu", nil), (unsigned long)displayIndex, (unsigned long)self.dataSource.numberOfPhotos];
+        }
     }
 
     self.overlayView.title = overlayTitle;