//
//  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