IOS-3384 enable CLCG to load cached images more quickly to allow for …

…faster perceived loading of book page. Enable loading the best cached image directly in CLCGImageView
ettore · Dec 3, 2015 · 7095dfb · 7095dfb
1 parent d530bca
commit 7095dfb
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Showing 4 changed files with 71 additions and 10 deletions.
diff --git a/CLCGImageLoader.h b/CLCGImageLoader.h
@@ -51,6 +51,18 @@ typedef void (^CLCGImageLoaderCallback)(UIImage *img, int http_status);
 
 @property(nonatomic,retain,readonly) NSCache *cache;
 
+/*!
+ Singleton instance of the CLCGImageLoader
+ */
++(CLCGImageLoader*)i;
+
+/*!
+ @return The largest size image currently stored in cache.
+ */
++(UIImage*)bestCachedImageForURL:(NSString*)normal_url
+                       retinaURL:(NSString*)retina_url
+                     retinaHDURL:(NSString*)retina_hd_url;
+
 /*! 
  @deprecated
  */

diff --git a/CLCGImageLoader.m b/CLCGImageLoader.m
@@ -80,16 +80,11 @@ +(ASIHTTPRequest*)loadImageForURL:(NSString*)normal_url
 
 
 
-
-
-+(ASIHTTPRequest*)loadImageForURL:(NSString*)normal_url
-                        retinaURL:(NSString*)retina_url
-                      retinaHDURL:(NSString*)retina_hd_url
-                         useCache:(BOOL)use_cache
-                            block:(CLCGImageLoaderCallback)block
++(NSURL*)screenImageURLForURL:(NSString*)normal_url
+                    retinaURL:(NSString*)retina_url
+                  retinaHDURL:(NSString*)retina_hd_url
 {
   NSURL *url = nil;
-  __block ASIHTTPRequest *req = nil;
   const CGFloat screen_scale = [UIScreen mainScreen].scale;
   const BOOL is_retina_hd = (screen_scale >= 3.0);
   const BOOL is_retina = (screen_scale >= 2.0);
@@ -109,7 +104,42 @@ +(ASIHTTPRequest*)loadImageForURL:(NSString*)normal_url
       && !clcg_str_isblank(normal_url)) {
     url = [[NSURL alloc] initWithString:normal_url];
   }
+  return url;
+}
+
+
++(UIImage*)bestCachedImageForURL:(NSString*)normal_url
+                       retinaURL:(NSString*)retina_url
+                     retinaHDURL:(NSString*)retina_hd_url
+{
+  UIImage *img = [[[CLCGImageLoader i] cache] objectForKey:retina_hd_url];
 
+  if (img == nil) {
+    img = [[[CLCGImageLoader i] cache] objectForKey:retina_url];
+  }
+
+  if (img == nil) {
+    img = [[[CLCGImageLoader i] cache] objectForKey:normal_url];
+  }
+
+  if (img) {
+    return img;
+  }
+
+  return nil;
+}
+
+
++(ASIHTTPRequest*)loadImageForURL:(NSString*)normal_url
+                        retinaURL:(NSString*)retina_url
+                      retinaHDURL:(NSString*)retina_hd_url
+                         useCache:(BOOL)use_cache
+                            block:(CLCGImageLoaderCallback)block
+{
+  __block ASIHTTPRequest *req = nil;
+  NSURL *url = [CLCGImageLoader screenImageURLForURL:normal_url
+                                           retinaURL:retina_url
+                                         retinaHDURL:retina_hd_url];
   if (url) {
     block = [block copy];//make sure it's on the heap
 
@@ -120,7 +150,6 @@ +(ASIHTTPRequest*)loadImageForURL:(NSString*)normal_url
         return nil;
       }
     }
-
     // configure the request
     req = [[ASIHTTPRequest alloc] initWithURL:url];
     [req addRequestHeader:@"Accept-Encoding" value:@"gzip"];
@@ -133,11 +162,12 @@ +(ASIHTTPRequest*)loadImageForURL:(NSString*)normal_url
       NSData *data = [req responseData];
       // TODO: we should likely use imageWithData:scale: instead. 
       UIImage *img = [UIImage imageWithData:data];
+
       if (img == nil) {
         [CLCGImageLoader reportErrorForRequest:req block:block];
       } else {
         if (use_cache) {
-          [[[CLCGImageLoader i] cache] setObject:img 
+          [[[CLCGImageLoader i] cache] setObject:img
                                           forKey:[[req originalURL] absoluteString]];
         }
         [self returnImage:img status:[req responseStatusCode] block:block];

diff --git a/CLCGImageView.h b/CLCGImageView.h
@@ -41,4 +41,8 @@ typedef void (^CLCGImageViewOnLoadCallback)(UIImage *img, int http_status);
              retinaURL:(NSString*)retina_url
            retinaHDURL:(NSString*)retina_hd_url;
 
+-(void)loadCachedImageIfPossibleForURL:(NSString*)normal_url
+                             retinaURL:(NSString*)retina_url
+                           retinaHDURL:(NSString*)retina_hd_url;
+
 @end
diff --git a/CLCGImageView.m b/CLCGImageView.m
@@ -68,6 +68,21 @@ -(void)loadImageForURL:(NSString*)normal_url
             retinaHDURL:nil];
 }
 
+
+-(void)loadCachedImageIfPossibleForURL:(NSString*)normal_url
+                             retinaURL:(NSString*)retina_url
+                           retinaHDURL:(NSString*)retina_hd_url
+{
+    UIImage *img = [CLCGImageLoader bestCachedImageForURL:normal_url
+                                                retinaURL:retina_url
+                                              retinaHDURL:retina_hd_url];
+    if (img) {
+      [self setImage:img];
+      return;
+    }
+}
+
+
 -(void)loadImageForURL:(NSString*)normal_url
              retinaURL:(NSString*)retina_url
            retinaHDURL:(NSString*)retina_hd_url