Support for a custom downloader and delegate to provide them

JTSImageViewController.podspec

@@ -1,11 +1,12 @@
 Pod::Spec.new do |s|
   s.name         = "JTSImageViewController"
-  s.version      = "1.5.1"
+  s.version      = "1.5.3"
   s.summary      = "An interactive iOS image viewer that does it all: double tap to zoom, flick to dismiss, et cetera."
-  s.homepage     = "https://github.com/jaredsinclair/JTSImageViewController"
+  s.homepage     = "https://github.com/brucehappy/JTSImageViewController"
   s.license      = { :type => 'MIT', :file => 'LICENSE'  }
-  s.author       = { "Jared Sinclair" => "desk@jaredsinclair.com" }
-  s.source       = { :git => "https://github.com/jaredsinclair/JTSImageViewController.git", :tag => s.version.to_s }
+  s.authors      = { "Jared Sinclair" => "desk@jaredsinclair.com",
+                     "Bruce Duncan" => "bduncan@rassilon.co" }
+  s.source       = { :git => "https://github.com/brucehappy/JTSImageViewController.git", :tag => s.version.to_s }
   s.platform     = :ios, '7.0'
   s.requires_arc = true
   s.frameworks   = 'UIKit', 'ImageIO', 'Accelerate'

Sample App/JTSImageVC/JTSImageVC/JTSViewController.m

@@ -12,6 +12,7 @@
 #import "JTSImageInfo.h"
 
 #define TRY_AN_ANIMATED_GIF 0
+#define TRY_AN_IMAGE_URL 0
 
 @interface JTSViewController ()
 
@@ -37,7 +38,9 @@ - (void)bigButtonTapped:(id)sender {
     // Create image info
     JTSImageInfo *imageInfo = [[JTSImageInfo alloc] init];
 #if TRY_AN_ANIMATED_GIF == 1
-    imageInfo.imageURL = [NSURL URLWithString:@"http://media.giphy.com/media/O3QpFiN97YjJu/giphy.gif"];
+    imageInfo.imageURL = [NSURL URLWithString:@"https://media.giphy.com/media/O3QpFiN97YjJu/giphy.gif"];
+#elif TRY_AN_IMAGE_URL == 1
+    imageInfo.imageURL = [NSURL URLWithString:@"https://upload.wikimedia.org/wikipedia/commons/6/67/Inside_the_Batad_rice_terraces.jpg"];
 #else
     imageInfo.image = self.bigImageButton.image;
 #endif

Source/JTSImageViewController.h

@@ -19,6 +19,8 @@
 @protocol JTSImageViewControllerInteractionsDelegate;
 @protocol JTSImageViewControllerAccessibilityDelegate;
 @protocol JTSImageViewControllerAnimationDelegate;
+@protocol JTSImageViewControllerDownloader;
+@protocol JTSImageViewControllerDownloaderDelegate;
 
 typedef NS_ENUM(NSInteger, JTSImageViewControllerMode) {
     JTSImageViewControllerMode_Image,
@@ -63,8 +65,10 @@ extern CGFloat const JTSImageViewController_DefaultBackgroundBlurRadius;
 
 @property (weak, nonatomic, readwrite) id <JTSImageViewControllerAnimationDelegate> animationDelegate;
 
+@property (weak, nonatomic, readonly) id <JTSImageViewControllerDownloaderDelegate> downloaderDelegate;
+
 /**
- Designated initializer.
+ Convenience initializer.
 
  @param imageInfo The source info for image and transition metadata. Required.
 
@@ -77,6 +81,25 @@ extern CGFloat const JTSImageViewController_DefaultBackgroundBlurRadius;
                              mode:(JTSImageViewControllerMode)mode
                   backgroundStyle:(JTSImageViewControllerBackgroundOptions)backgroundOptions;
 
+/**
+ Designated initializer.
+
+ @param imageInfo The source info for image and transition metadata. Required.
+
+ @param mode The mode to be used. (JTSImageViewController has an alternate alt text mode). Required.
+
+ @param backgroundStyle Currently, either scaled-and-dimmed, or scaled-dimmed-and-blurred.
+ The latter is like Tweetbot 3.0's background style.
+
+ @param downloaderDelegate The downloaderDelegate to be used. Optional.
+ */
+
+- (instancetype)initWithImageInfo:(JTSImageInfo *)imageInfo
+                             mode:(JTSImageViewControllerMode)mode
+                  backgroundStyle:(JTSImageViewControllerBackgroundOptions)backgroundOptions
+               downloaderDelegate:(id <JTSImageViewControllerDownloaderDelegate>)downloaderDelegate;
+
+
 /**
  JTSImageViewController is presented from viewController as a UIKit modal view controller.
 
@@ -229,6 +252,51 @@ extern CGFloat const JTSImageViewController_DefaultBackgroundBlurRadius;
 
 @end
 
+///---------------------------------------------------------------------------------------------------
+/// Downloader
+///---------------------------------------------------------------------------------------------------
+
+@protocol JTSImageViewControllerDownloader <NSObject>
+
+/**
+ The number of bytes that are expected to be recieved.
+ */
+@property (readonly) int64_t countOfBytesExpectedToReceive;
+
+/**
+ The number of bytes that have been received.
+ */
+@property (readonly) int64_t countOfBytesReceived;
+
+/**
+ Called to begin downloading the image.
+
+ Calls block with non-nil value on success, and nil on failure.
+ */
+- (void)downloadImage:(void (^)(UIImage *image))completion;
+
+@optional
+
+/**
+ Called to cancel the download if it is in progress.
+ */
+- (void)cancel;
+
+@end
+
+///---------------------------------------------------------------------------------------------------
+/// Downloader Delegate
+///---------------------------------------------------------------------------------------------------
+
+@protocol JTSImageViewControllerDownloaderDelegate <NSObject>
+
+/**
+ Called to retrieve a downloader for the given image information.
+ */
+- (id <JTSImageViewControllerDownloader>)downloaderForImageInfo:(JTSImageInfo *)imageInfo;
+
+@end
+
 
 
 

Source/JTSImageViewController.m

@@ -12,6 +12,8 @@
 #import "UIImage+JTSImageEffects.h"
 #import "UIApplication+JTSImageViewController.h"
 
+#pragma mark - Definitions
+
 CG_INLINE CGFLOAT_TYPE JTSImageFloatAbs(CGFLOAT_TYPE aFloat) {
 #if CGFLOAT_IS_DOUBLE
     return fabs(aFloat);
@@ -61,18 +63,30 @@ CG_INLINE CGFLOAT_TYPE JTSImageFloatAbs(CGFLOAT_TYPE aFloat) {
     BOOL imageDownloadFailed;
 } JTSImageViewControllerFlags;
 
+// Private Downloader Interface
+@interface __PrivateJTSImageViewControllerDownloader: NSObject <JTSImageViewControllerDownloader>
+- (id)initWithImageInfo:(JTSImageInfo *)imageInfo;
+- (int64_t)countOfBytesExpectedToReceive;
+- (int64_t)countOfBytesReceived;
+@property (strong, nonatomic, readwrite) NSURLSessionDataTask *task;
+@property (strong, nonatomic, readwrite) JTSImageInfo *info;
+@end
+
 #define USE_DEBUG_SLOW_ANIMATIONS 0
 
 ///--------------------------------------------------------------------------------------------------------------------
 /// Anonymous Category
 ///--------------------------------------------------------------------------------------------------------------------
 
+#pragma mark - Public Interface
+
 @interface JTSImageViewController ()
 <
     UIScrollViewDelegate,
     UITextViewDelegate,
     UIViewControllerTransitioningDelegate,
-    UIGestureRecognizerDelegate
+    UIGestureRecognizerDelegate,
+    JTSImageViewControllerDownloaderDelegate
 >
 
 // General Info
@@ -115,7 +129,7 @@ @interface JTSImageViewController ()
 @property (assign, nonatomic) UIOffset imageDragOffsetFromImageCenter;
 
 // Image Downloading
-@property (strong, nonatomic) NSURLSessionDataTask *imageDownloadDataTask;
+@property (strong, nonatomic) id<JTSImageViewControllerDownloader> imageDownloader;
 @property (strong, nonatomic) NSTimer *downloadProgressTimer;
 
 @end
@@ -124,21 +138,30 @@ @interface JTSImageViewController ()
 /// Implementation
 ///--------------------------------------------------------------------------------------------------------------------
 
-@implementation JTSImageViewController
-
 #pragma mark - Public
 
+@implementation JTSImageViewController
+
 - (instancetype)initWithImageInfo:(JTSImageInfo *)imageInfo
                              mode:(JTSImageViewControllerMode)mode
                   backgroundStyle:(JTSImageViewControllerBackgroundOptions)backgroundOptions {
 
+    return [self initWithImageInfo:imageInfo mode:mode backgroundStyle:backgroundOptions downloaderDelegate:nil];
+}
+
+- (instancetype)initWithImageInfo:(JTSImageInfo *)imageInfo
+                             mode:(JTSImageViewControllerMode)mode
+                  backgroundStyle:(JTSImageViewControllerBackgroundOptions)backgroundOptions
+               downloaderDelegate:(id<JTSImageViewControllerDownloaderDelegate>)downloaderDelegate {
+
     self = [super initWithNibName:nil bundle:nil];
     if (self) {
         [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(deviceOrientationDidChange:) name:UIDeviceOrientationDidChangeNotification object:nil];
         _imageInfo = imageInfo;
         _currentSnapshotRotationTransform = CGAffineTransformIdentity;
         _mode = mode;
         _backgroundOptions = backgroundOptions;
+        _downloaderDelegate = downloaderDelegate;
         if (_mode == JTSImageViewControllerMode_Image) {
             [self setupImageAndDownloadIfNecessary:imageInfo];
         }
@@ -203,7 +226,9 @@ - (void)dismiss:(BOOL)animated {
 
 - (void)dealloc {
     [[NSNotificationCenter defaultCenter] removeObserver:self name:UIDeviceOrientationDidChangeNotification object:nil];
-    [_imageDownloadDataTask cancel];
+    if ([self.imageDownloader respondsToSelector:NSSelectorFromString(@"cancel:")]) {
+        [self.imageDownloader cancel];
+    }
     [self cancelProgressTimer];
 }
 
@@ -383,6 +408,12 @@ one landscape orientation to the other (or from one portrait orientation to anot
     }
 }
 
+#pragma mark - Downloader Delegate
+
+- (id <JTSImageViewControllerDownloader>)downloaderForImageInfo:(JTSImageInfo *)imageInfo {
+    return [[__PrivateJTSImageViewControllerDownloader alloc] initWithImageInfo:imageInfo];
+}
+
 #pragma mark - Setup
 
 - (void)setupImageAndDownloadIfNecessary:(JTSImageInfo *)imageInfo {
@@ -396,8 +427,18 @@ - (void)setupImageAndDownloadIfNecessary:(JTSImageInfo *)imageInfo {
         BOOL fromDisk = [imageInfo.imageURL.absoluteString hasPrefix:@"file://"];
         _flags.imageIsBeingReadFromDisk = fromDisk;
 
+        id<JTSImageViewControllerDownloaderDelegate> delegate = self.downloaderDelegate != nil ? self.downloaderDelegate : self;
+        self.imageDownloader = [delegate downloaderForImageInfo:imageInfo];
+
+        //Setup the timer before we call download image, since its possible that
+        //it may immediately call cancelProgressTimer BEFORE we call startProgressTimer
+        //If that happens, it will invalidate the timer we create here via the call
+        //to setup, and then when we call start, we will simeply return since the timer
+        //will be nil
+        [self setupProgressTimer];
+
         typeof(self) __weak weakSelf = self;
-        NSURLSessionDataTask *task = [JTSSimpleImageDownloader downloadImageForURL:imageInfo.imageURL canonicalURL:imageInfo.canonicalImageURL completion:^(UIImage *image) {
+        [self.imageDownloader downloadImage:^(UIImage *image){
             typeof(self) strongSelf = weakSelf;
             [strongSelf cancelProgressTimer];
             if (image) {
@@ -415,8 +456,6 @@ - (void)setupImageAndDownloadIfNecessary:(JTSImageInfo *)imageInfo {
             }
         }];
 
-        self.imageDownloadDataTask = task;
-
         [self startProgressTimer];
     }
 }
@@ -1864,30 +1903,37 @@ - (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRequire
 
 #pragma mark - Progress Bar
 
-- (void)startProgressTimer {
+- (void)setupProgressTimer {
     self.downloadProgressTimer = [[NSTimer alloc] initWithFireDate:[NSDate date]
                                                           interval:0.05
                                                             target:self
                                                           selector:@selector(progressTimerFired:)
                                                           userInfo:nil
                                                            repeats:YES];
-    [[NSRunLoop mainRunLoop] addTimer:self.downloadProgressTimer forMode:NSRunLoopCommonModes];
+}
+
+- (void)startProgressTimer {
+    if (self.downloadProgressTimer != nil) {
+        [[NSRunLoop mainRunLoop] addTimer:self.downloadProgressTimer forMode:NSRunLoopCommonModes];
+    }
 }
 
 - (void)cancelProgressTimer {
-    [self.downloadProgressTimer invalidate];
-    self.downloadProgressTimer = nil;
+    if (self.downloadProgressTimer != nil) {
+        [self.downloadProgressTimer invalidate];
+        self.downloadProgressTimer = nil;
+    }
 }
 
 - (void)progressTimerFired:(NSTimer *)timer {
     CGFloat progress = 0;
-    CGFloat bytesExpected = self.imageDownloadDataTask.countOfBytesExpectedToReceive;
+    CGFloat bytesExpected = self.imageDownloader.countOfBytesExpectedToReceive;
     if (bytesExpected > 0 && _flags.imageIsBeingReadFromDisk == NO) {
         [UIView animateWithDuration:0.25 delay:0 options:UIViewAnimationOptionBeginFromCurrentState | UIViewAnimationOptionCurveLinear animations:^{
             self.spinner.alpha = 0;
             self.progressView.alpha = 1;
         } completion:nil];
-        progress = self.imageDownloadDataTask.countOfBytesReceived / bytesExpected;
+        progress = self.imageDownloader.countOfBytesReceived / bytesExpected;
     }
     self.progressView.progress = progress;
 }
@@ -1971,5 +2017,35 @@ - (NSString *)defaultAccessibilityHintForScrollView:(BOOL)zoomedIn {
 
 @end
 
+///--------------------------------------------------------------------------------------------------------------------
+/// Private Downloader Implementation
+///--------------------------------------------------------------------------------------------------------------------
+
+#pragma mark - Private Downloader
+@implementation __PrivateJTSImageViewControllerDownloader
+
+- (instancetype)initWithImageInfo:(JTSImageInfo *)imageInfo {
+    self = [super init];
+    _info = imageInfo;
+    return self;
+}
+
+- (void)downloadImage:(void (^)(UIImage *))completion {
+    _task = [JTSSimpleImageDownloader downloadImageForURL:_info.imageURL canonicalURL:_info.canonicalImageURL completion:completion];
+}
+
+- (void)cancel {
+    [_task cancel];
+}
+
+- (int64_t)countOfBytesExpectedToReceive {
+    return _task.countOfBytesExpectedToReceive;
+}
+
+- (int64_t)countOfBytesReceived {
+    return _task.countOfBytesReceived;
+}
+
+@end