Clarify how title-text delegate method is intended to be used

Example/NYTPhotoViewer/NYTViewController.m

@@ -45,7 +45,6 @@ - (void)updateImagesOnPhotosViewController:(NYTPhotosViewController *)photosView
     dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(updateImageDelay * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
         for (NYTExamplePhoto *photo in photos) {
             if (!photo.image && !photo.imageData) {
-                // Photo credit: Nic Lehoux
                 photo.image = [UIImage imageNamed:@"NYTimesBuilding"];
                 [photosViewController updateImageForPhoto:photo];
             }
@@ -99,7 +98,7 @@ + (NSArray *)newTestPhotos {
 
         photo.attributedCaptionTitle = [[NSAttributedString alloc] initWithString:@(i + 1).stringValue attributes:@{NSForegroundColorAttributeName: [UIColor whiteColor], NSFontAttributeName: [UIFont preferredFontForTextStyle:UIFontTextStyleBody]}];
         photo.attributedCaptionSummary = [[NSAttributedString alloc] initWithString:caption attributes:@{NSForegroundColorAttributeName: [UIColor lightGrayColor], NSFontAttributeName: [UIFont preferredFontForTextStyle:UIFontTextStyleBody]}];
-        photo.attributedCaptionCredit = [[NSAttributedString alloc] initWithString:@"credit" attributes:@{NSForegroundColorAttributeName: [UIColor grayColor], NSFontAttributeName: [UIFont preferredFontForTextStyle:UIFontTextStyleCaption1]}];
+        photo.attributedCaptionCredit = [[NSAttributedString alloc] initWithString:@"NYT Building Photo Credit: Nic Lehoux" attributes:@{NSForegroundColorAttributeName: [UIColor grayColor], NSFontAttributeName: [UIFont preferredFontForTextStyle:UIFontTextStyleCaption1]}];
 
         [photos addObject:photo];
     }
@@ -156,6 +155,14 @@ - (NSDictionary *)photosViewController:(NYTPhotosViewController *)photosViewCont
     return nil;
 }
 
+- (NSString *)photosViewController:(NYTPhotosViewController *)photosViewController titleForPhoto:(id<NYTPhoto>)photo atIndex:(NSUInteger)photoIndex totalPhotoCount:(NSUInteger)totalPhotoCount {
+    if ([photo isEqual:self.photos[NYTViewControllerPhotoIndexCustomEverything]]) {
+        return [NSString stringWithFormat:@"%lu/%lu", (unsigned long)photoIndex+1, (unsigned long)totalPhotoCount];
+    }
+
+    return nil;
+}
+
 - (void)photosViewController:(NYTPhotosViewController *)photosViewController didNavigateToPhoto:(id <NYTPhoto>)photo atIndex:(NSUInteger)photoIndex {
     NSLog(@"Did Navigate To Photo: %@ identifier: %lu", photo, (unsigned long)photoIndex);
 }

Pod/Classes/ios/NYTPhotosViewController.h

@@ -166,15 +166,18 @@ extern NSString * const NYTPhotosViewControllerDidDismissNotification;
 - (UIView * _Nullable)photosViewController:(NYTPhotosViewController *)photosViewController captionViewForPhoto:(id <NYTPhoto>)photo;
 
 /**
- *  Returns a string to display as the title of a photo.
+ *  Returns a string to display as the title in the navigation-bar area for a photo.
+ *
+ *  This small area of the screen is not intended to display a caption or similar information about the photo itself. (NYTPhotoViewer is designed to provide this information in the capton view, and as such the `NYTPhoto` protocol provides properties for the title, summary, and credit for each photo.) Instead, consider using this delegate method to customize how your app displays the user's progress through a set of photos.
  *
  *  @param photosViewController The `NYTPhotosViewController` instance that sent the delegate message.
- *  @param photo                The photo object over which to display the title.
+ *  @param photo                The photo object for which to display the title.
  *  @param photoIndex           The index of the photo.
+ *  @param totalPhotoCount      The number of photos beign displayed by the photo viewer.
  *
- *  @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.
+ *  @return The text to display as the navigation-item title for the given photo. Return `nil` to show a default title like "1 of 4" indicating progress in a slideshow, or an empty string to hide this text entirely.
  */
-- (NSString * _Nullable)photosViewController:(NYTPhotosViewController *)photosViewController titleForPhoto:(id <NYTPhoto>)photo atIndex:(NSUInteger)photoIndex;
+- (NSString * _Nullable)photosViewController:(NYTPhotosViewController *)photosViewController titleForPhoto:(id <NYTPhoto>)photo atIndex:(NSUInteger)photoIndex totalPhotoCount:(NSUInteger)totalPhotoCount;
 
 /**
  *  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

@@ -225,19 +225,18 @@ - (void)updateOverlayInformation {
 
     NSUInteger photoIndex = [self.dataSource indexOfPhoto:self.currentlyDisplayedPhoto];
 
-    if ([self.delegate respondsToSelector:@selector(photosViewController:titleForPhoto:atIndex:)]) {
-        overlayTitle = [self.delegate photosViewController:self titleForPhoto:self.currentlyDisplayedPhoto atIndex:photoIndex];
+    if ([self.delegate respondsToSelector:@selector(photosViewController:titleForPhoto:atIndex:totalPhotoCount:)]) {
+        overlayTitle = [self.delegate photosViewController:self titleForPhoto:self.currentlyDisplayedPhoto atIndex:photoIndex totalPhotoCount:self.dataSource.numberOfPhotos];
     }
 
-    if (!overlayTitle) {
+    if (!overlayTitle && self.dataSource.numberOfPhotos > 1) {
         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];
-        }
+
+        overlayTitle = [NSString localizedStringWithFormat:NSLocalizedString(@"%lu of %lu", nil), (unsigned long)displayIndex, (unsigned long)self.dataSource.numberOfPhotos];
     }
 
     self.overlayView.title = overlayTitle;