Added a utility method for checking whether an image data is GIF.

Source/JTSAnimatedGIFUtility.h

@@ -12,6 +12,8 @@
 
 + (BOOL)imageURLIsAGIF:(NSString *)imageURL;
 
++ (BOOL)imageDataIsAGIF:(NSData *)imageData;
+
 /*
  UIImage *animation = [UIImage animatedImageWithAnimatedGIFData:theData];
 

Source/JTSAnimatedGIFUtility.m

@@ -24,6 +24,33 @@ + (BOOL)imageURLIsAGIF:(NSString *)imageURL {
     return [[imageURL substringFromIndex:[imageURL length] - 3] isEqualToString:@"gif"];
 }
 
+static NSString * contentTypeForImageData(NSData * data) {
+    uint8_t c;
+    [data getBytes:&c length:1];
+
+    switch (c) {
+        case 0xFF:
+            return @"image/jpeg";
+        case 0x89:
+            return @"image/png";
+        case 0x47:
+            return @"image/gif";
+        case 0x49:
+        case 0x4D:
+            return @"image/tiff";
+    }
+    return nil;
+}
+
++ (BOOL)imageDataIsAGIF:(NSData *)imageData {
+    NSString *imageType = contentTypeForImageData(imageData);
+    if ([imageType isEqualToString:@"image/gif"]) {
+        return YES;
+    } else {
+        return NO;
+    }
+}
+
 static int delayCentisecondsForImageAtIndex(CGImageSourceRef const source, size_t const i) {
     int delayCentiseconds = 1;
     CFDictionaryRef const properties = CGImageSourceCopyPropertiesAtIndex(source, i, NULL);
@@ -104,21 +131,10 @@ static void releaseImages(size_t const count, CGImageRef const images[count]) {
     int delayCentiseconds[count]; // in centiseconds
     createImagesAndDelays(source, count, images, delayCentiseconds);
     int const totalDurationCentiseconds = sum(count, delayCentiseconds);
-    UIImage *image = nil;
-    if (totalDurationCentiseconds == 0 || count == 1) {
-        // This can't be animated, so don't bother trying to create an animated image.
-        CGImageRef imageRef = CGImageSourceCreateImageAtIndex(source, 0, NULL);
-        if (imageRef) {
-            image = [UIImage imageWithCGImage:imageRef];
-            CGImageRelease(imageRef);
-        }
-    } else {
-        NSArray *const frames = frameArray(count, images, delayCentiseconds, totalDurationCentiseconds);
-        UIImage *const animation = [UIImage animatedImageWithImages:frames duration:(NSTimeInterval)totalDurationCentiseconds / 100.0];
-        releaseImages(count, images);
-        image = animation;
-    }
-    return image;
+    NSArray *const frames = frameArray(count, images, delayCentiseconds, totalDurationCentiseconds);
+    UIImage *const animation = [UIImage animatedImageWithImages:frames duration:(NSTimeInterval)totalDurationCentiseconds / 100.0];
+    releaseImages(count, images);
+    return animation;
 }
 
 static UIImage *animatedImageWithAnimatedGIFReleasingImageSource(CGImageSourceRef source CF_CONSUMED) {

Source/JTSImageViewController.h

@@ -8,7 +8,7 @@
 
 @import UIKit;
 
-#import "JTSImageInfo.h"
+#import "JTSMediaInfo.h"
 
 ///--------------------------------------------------------------------------------------------------------------------
 /// Definitions
@@ -45,9 +45,9 @@ extern CGFloat const JTSImageViewController_DefaultBackgroundBlurRadius;
 
 @interface JTSImageViewController : UIViewController
 
-@property (strong, nonatomic, readonly) JTSImageInfo *imageInfo;
+@property (strong, nonatomic, readonly) NSArray *imageInfoArray;//JTSMediaInfo *imageInfo;
 
-@property (strong, nonatomic, readonly) UIImage *image;
+@property (strong, nonatomic, readonly) NSMutableArray *imageArray;
 
 @property (assign, nonatomic, readonly) JTSImageViewControllerMode mode;
 
@@ -73,10 +73,15 @@ extern CGFloat const JTSImageViewController_DefaultBackgroundBlurRadius;
  @param backgroundStyle Currently, either scaled-and-dimmed, or scaled-dimmed-and-blurred. 
  The latter is like Tweetbot 3.0's background style.
  */
-- (instancetype)initWithImageInfo:(JTSImageInfo *)imageInfo
+- (instancetype)initWithImageInfo:(JTSMediaInfo *)imageInfo
                              mode:(JTSImageViewControllerMode)mode
                   backgroundStyle:(JTSImageViewControllerBackgroundOptions)backgroundOptions;
 
+- (instancetype)initWIthImageInfoArray:(NSArray *)imageInfoArray
+                         startingIndex:(int)startingIndex
+                                  mode:(JTSImageViewControllerMode)mode
+                       backgroundStyle:(JTSImageViewControllerBackgroundOptions)backgroundOptions;
+
 /**
  JTSImageViewController is presented from viewController as a UIKit modal view controller.
 
@@ -86,13 +91,17 @@ extern CGFloat const JTSImageViewController_DefaultBackgroundBlurRadius;
  Next, there is an animated transition to a full-screen image viewer.
  */
 - (void)showFromViewController:(UIViewController *)viewController
-                    transition:(JTSImageViewControllerTransition)transition;
+                    transition:(JTSImageViewControllerTransition)transition
+                    completion:(void (^)(void))completion;
 
 /**
  Dismisses the image viewer. Must not be called while previous presentation or dismissal is still in flight.
  */
 - (void)dismiss:(BOOL)animated;
 
+-(void)pauseVideoPlayback;
+-(void)resumeVideoPlayback;
+
 @end
 
 ///--------------------------------------------------------------------------------------------------------------------