Swizzled UIImage imageNamed for iPhone 5

UIImage+Retina4.h

//
//  UIImage+Retina4.h
//  StunOMatic
//
//  Created by Benjamin Stahlhood on 9/12/12.
//  Updated by noradaiko on 9/26/12.
//  Copyright (c) 2012 DS Media Labs. All rights reserved.
//  Copyright (c) 2012 noradaiko. All rights reserved.
//

#import <UIKit/UIKit.h>

@interface UIImage (Retina4)

@end

UIImage+Retina4.m

//
//  UIImage+Retina4.m
//  StunOMatic
//
//  Created by Benjamin Stahlhood on 9/12/12.
//  Updated by noradaiko on 9/26/12.
//  Copyright (c) 2012 DS Media Labs. All rights reserved.
//  Copyright (c) 2012 noradaiko. All rights reserved.
//

#import "UIImage+Retina4.h"
#import <objc/objc-runtime.h>

static Method origImageNamedMethod = nil;

@implementation UIImage (Retina4)

+ (void)initialize
{
    if(!origImageNamedMethod)
    {
        origImageNamedMethod = class_getClassMethod(self, @selector(imageNamed:));
/*
        Method oldMethod = class_getClassMethod(self, @selector(imageNamed:));
        Method newMethod = class_getClassMethod(self, @selector(retina4ImageNamed:));
        NSLog(@"oldMethod name is %@, imp is %x", NSStringFromSelector(method_getName(oldMethod)), (NSInteger)method_getImplementation(oldMethod));
        NSLog(@"newMethod name is %@, imp is %x", NSStringFromSelector(method_getName(newMethod)), (NSInteger)method_getImplementation(newMethod));
*/
        method_exchangeImplementations(origImageNamedMethod,
                                       class_getClassMethod(self, @selector(retina4ImageNamed:)));
/*
        NSLog(@"oldMethod name is %@, imp is %x", NSStringFromSelector(method_getName(oldMethod)), (NSInteger)method_getImplementation(oldMethod));
        NSLog(@"newMethod name is %@, imp is %x", NSStringFromSelector(method_getName(newMethod)), (NSInteger)method_getImplementation(newMethod));
 */
    }
}

+ (UIImage *)retina4ImageNamed:(NSString *)imageName
{
    NSLog(@"Loading image named => %@", imageName);
    NSMutableString *imageNameMutable = [imageName mutableCopy];
    NSRange retinaAtSymbol = [imageName rangeOfString:@"@"];
    if (retinaAtSymbol.location != NSNotFound) {
        [imageNameMutable insertString:@"-568h" atIndex:retinaAtSymbol.location];
    } else {
        CGFloat screenHeight = [UIScreen mainScreen].bounds.size.height;
        if ([UIScreen mainScreen].scale == 2.f && screenHeight == 568.0f) {
            NSRange dot = [imageName rangeOfString:@"."];
            if (dot.location != NSNotFound) {
                [imageNameMutable insertString:@"-568h" atIndex:dot.location];
            } else {
                [imageNameMutable appendString:@"-568h"];
            }
        }
    }
    
    UIImage* ret = [UIImage retina4ImageNamed:imageNameMutable];
    if (ret)
        return ret;
    else
        return [UIImage retina4ImageNamed:imageName];
}

@end

UIImageRetina4.h

//
//  UIImage+Retina4.h
//  StunOMatic
//
//  Created by Benjamin Stahlhood on 9/12/12.
//  Updated by noradaiko on 9/26/12.
//  Copyright (c) 2012 DS Media Labs. All rights reserved.
//  Copyright (c) 2012 noradaiko. All rights reserved.
//

#import <UIKit/UIKit.h>

@interface UIImage (Retina4)

@end

UIImageRetina4.m

//
//  UIImage+Retina4.m
//  StunOMatic
//
//  Created by Benjamin Stahlhood on 9/12/12.
//  Updated by noradaiko on 9/26/12.
//  Copyright (c) 2012 DS Media Labs. All rights reserved.
//  Copyright (c) 2012 noradaiko. All rights reserved.
//

#import "UIImage+Retina4.h"
#import <objc/runtime.h>
#import <objc/message.h>

static Method origImageNamedMethod = nil;

@implementation UIImage (Retina4)

+ (void)initialize
{
    if(!origImageNamedMethod)
    {
        origImageNamedMethod = class_getClassMethod(self, @selector(imageNamed:));
/*
        Method oldMethod = class_getClassMethod(self, @selector(imageNamed:));
        Method newMethod = class_getClassMethod(self, @selector(retina4ImageNamed:));
        NSLog(@"oldMethod name is %@, imp is %x", NSStringFromSelector(method_getName(oldMethod)), (NSInteger)method_getImplementation(oldMethod));
        NSLog(@"newMethod name is %@, imp is %x", NSStringFromSelector(method_getName(newMethod)), (NSInteger)method_getImplementation(newMethod));
*/
        method_exchangeImplementations(origImageNamedMethod,
                                       class_getClassMethod(self, @selector(retina4ImageNamed:)));
/*
        NSLog(@"oldMethod name is %@, imp is %x", NSStringFromSelector(method_getName(oldMethod)), (NSInteger)method_getImplementation(oldMethod));
        NSLog(@"newMethod name is %@, imp is %x", NSStringFromSelector(method_getName(newMethod)), (NSInteger)method_getImplementation(newMethod));
 */
    }
}

+ (UIImage *)retina4ImageNamed:(NSString *)imageName
{
    NSLog(@"Loading image named => %@", imageName);
    NSMutableString *imageNameMutable = [imageName mutableCopy];
    NSRange retinaAtSymbol = [imageName rangeOfString:@"@"];
    if (retinaAtSymbol.location != NSNotFound) {
        [imageNameMutable insertString:@"-568h" atIndex:retinaAtSymbol.location];
    } else {
        CGFloat screenHeight = [UIScreen mainScreen].bounds.size.height;
        if ([UIScreen mainScreen].scale == 2.f && screenHeight == 568.0f) {
            NSRange dot = [imageName rangeOfString:@"."];
            if (dot.location != NSNotFound) {
                [imageNameMutable insertString:@"-568h" atIndex:dot.location];
            } else {
                [imageNameMutable appendString:@"-568h"];
            }
        }
    }
    
    UIImage* ret = [UIImage retina4ImageNamed:imageNameMutable];
    if (ret)
        return ret;
    else
        return [UIImage retina4ImageNamed:imageName];
}

@end