From 9d52266f823daf5cb83e3eebe1b9f57594bc9d4a Mon Sep 17 00:00:00 2001
From: matt handler <matt.handler@gmail.com>
Date: Wed, 20 Apr 2011 14:39:20 -0400
Subject: first commit

---
 Classes/AsyncImageView.m | 144 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 144 insertions(+)
 create mode 100644 Classes/AsyncImageView.m

(limited to 'Classes/AsyncImageView.m')

diff --git a/Classes/AsyncImageView.m b/Classes/AsyncImageView.m
new file mode 100644
index 0000000..d978e82
--- /dev/null
+++ b/Classes/AsyncImageView.m
@@ -0,0 +1,144 @@
+//
+//  AsyncImageView.m
+//  Postcard
+//
+//  Created by markj on 2/18/09.
+//  Copyright 2009 Mark Johnson. You have permission to copy parts of this code into your own projects for any use.
+//  www.markj.net
+//
+
+#import "AsyncImageView.h"
+
+@interface UIImage (Extras)
+
+- (UIImage*)imageByScalingAndCroppingForSize:(CGSize)targetSize;
+
+@end
+
+@implementation UIImage (Extras)
+
+#pragma mark -
+#pragma mark Scale and crop image
+
+- (UIImage*)imageByScalingAndCroppingForSize:(CGSize)targetSize
+{
+	UIImage *sourceImage = self;
+	UIImage *newImage = nil;        
+	CGSize imageSize = sourceImage.size;
+	CGFloat width = imageSize.width;
+	CGFloat height = imageSize.height;
+	CGFloat targetWidth = targetSize.width;
+	CGFloat targetHeight = targetSize.height;
+	CGFloat scaleFactor = 0.0;
+	CGFloat scaledWidth = targetWidth;
+	CGFloat scaledHeight = targetHeight;
+	CGPoint thumbnailPoint = CGPointMake(0.0,0.0);
+	
+	if (CGSizeEqualToSize(imageSize, targetSize) == NO) 
+	{
+        CGFloat widthFactor = targetWidth / width;
+        CGFloat heightFactor = targetHeight / height;
+		
+        if (widthFactor > heightFactor) 
+			scaleFactor = widthFactor; // scale to fit height
+        else
+			scaleFactor = heightFactor; // scale to fit width
+        scaledWidth  = width * scaleFactor;
+        scaledHeight = height * scaleFactor;
+		
+        // center the image
+        if (widthFactor > heightFactor)
+		{
+			thumbnailPoint.y = (targetHeight - scaledHeight) * 0.5; 
+		}
+        else 
+			if (widthFactor < heightFactor)
+			{
+				thumbnailPoint.x = (targetWidth - scaledWidth) * 0.5;
+			}
+	}       
+	
+	UIGraphicsBeginImageContext(targetSize); // this will crop
+	
+	CGRect thumbnailRect = CGRectZero;
+	thumbnailRect.origin = thumbnailPoint;
+	thumbnailRect.size.width  = scaledWidth;
+	thumbnailRect.size.height = scaledHeight;
+	
+	[sourceImage drawInRect:thumbnailRect];
+	
+	newImage = UIGraphicsGetImageFromCurrentImageContext();
+	if(newImage == nil) 
+        NSLog(@"could not scale image");
+	
+	//pop the context to get back to the default
+	UIGraphicsEndImageContext();
+	return newImage;
+}
+
+@end
+
+
+// This class demonstrates how the URL loading system can be used to make a UIView subclass
+// that can download and display an image asynchronously so that the app doesn't block or freeze
+// while the image is downloading. It works fine in a UITableView or other cases where there
+// are multiple images being downloaded and displayed all at the same time. 
+
+@implementation AsyncImageView
+
+- (void)dealloc {
+	[connection cancel]; //in case the URL is still downloading
+	[connection release];
+	[data release]; 
+    [super dealloc];
+}
+
+
+- (void)loadImageFromURL:(NSURL*)url {
+	NSLog(@"%@",url);
+	if (connection!=nil) { [connection release]; } //in case we are downloading a 2nd image
+	if (data!=nil) { [data release]; }
+	
+	NSURLRequest* request = [NSURLRequest requestWithURL:url cachePolicy:NSURLRequestUseProtocolCachePolicy timeoutInterval:60.0];
+	connection = [[NSURLConnection alloc] initWithRequest:request delegate:self]; //notice how delegate set to self object
+	//TODO error handling, what if connection is nil?
+}
+
+
+//the URL connection calls this repeatedly as data arrives
+- (void)connection:(NSURLConnection *)theConnection didReceiveData:(NSData *)incrementalData {
+	if (data==nil) { data = [[NSMutableData alloc] initWithCapacity:2048]; } 
+	[data appendData:incrementalData];
+}
+
+//the URL connection calls this once all the data has downloaded
+- (void)connectionDidFinishLoading:(NSURLConnection*)theConnection {
+	//so self data now has the complete image 
+	[connection release];
+	connection=nil;
+	if ([[self subviews] count]>0) {
+		//then this must be another image, the old one is still in subviews
+		[[[self subviews] objectAtIndex:0] removeFromSuperview]; //so remove it (releases it also)
+	}
+	
+	//make an image view for the image
+	UIImageView* imageView = [[[UIImageView alloc] initWithImage:[[UIImage imageWithData:data] imageByScalingAndCroppingForSize:CGSizeMake(100,100)]] autorelease];
+	//make sizing choices based on your needs, experiment with these. maybe not all the calls below are needed.
+	imageView.contentMode = UIViewContentModeScaleAspectFill;
+	imageView.autoresizingMask = ( UIViewAutoresizingFlexibleWidth || UIViewAutoresizingFlexibleHeight );
+	[self addSubview:imageView];
+	imageView.frame = self.bounds;
+	[imageView setNeedsLayout];
+	[self setNeedsLayout];
+
+	[data release]; //don't need this any more, its in the UIImageView now
+	data=nil;
+}
+
+//just in case you want to get the image directly, here it is in subviews
+- (UIImage*) image {
+	UIImageView* iv = [[self subviews] objectAtIndex:0];
+	return [iv image];
+}
+
+@end
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