Add asynchronous setImage: with completion block

dingbat · Jul 16, 2013 · 1c526ce · 1c526ce
1 parent 61b5419
commit 1c526ce
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diff --git a/FaceImageView/FaceImageView.h b/FaceImageView/FaceImageView.h
@@ -15,4 +15,6 @@
 
 @property (nonatomic, readonly) int numberOfFacesDetected;
 
+- (void) setImage:(UIImage *)image completion:(void(^)(void))block;
+
 @end
diff --git a/FaceImageView/FaceImageView.m b/FaceImageView/FaceImageView.m
@@ -86,6 +86,22 @@ - (void) calculateCentroidOfFaceLocations
     _centroid = centroid;
 }
 
+- (void) setImage:(UIImage *)image completion:(void(^)(void))block
+{
+    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^
+                   {
+                       [self setImage:image];
+
+                       dispatch_async(dispatch_get_main_queue(), ^
+                                      {
+                                          [self setNeedsDisplay];
+
+                                          if (block)
+                                              block();
+                                      });
+                   });
+}
+
 - (void) setImage:(UIImage *)image
 {
     _image = image;

diff --git a/readme.md b/readme.md
@@ -28,6 +28,12 @@ imageView.image = <UIImage>;
 [self.view addSubview:imageView];
 ```
 
+It may also be wise to set the image asynchronously, as face detection can sometimes take a second:
+
+```
+[imageView setImage:<UIImage> completion:^{}];
+```
+
 Demo App
 ---------