SDWebImage/SDWebImageCompat.m

//
//  SDWebImageCompat.m
//  SDWebImage
//
//  Created by Olivier Poitrey on 11/12/12.
//  Copyright (c) 2012 Dailymotion. All rights reserved.
//

#import "SDWebImageCompat.h"

#if !__has_feature(objc_arc)
#error SDWebImage is ARC only. Either turn on ARC for the project or use -fobjc-arc flag
#endif

inline UIImage *SDScaledImageForKey(NSString *key, UIImage *image) {
    if (!image) {
        return nil;
    }
    
    if ([image.images count] > 0) {
        NSMutableArray *scaledImages = [NSMutableArray array];

        for (UIImage *tempImage in image.images) {
            [scaledImages addObject:SDScaledImageForKey(key, tempImage)];
        }

        return [UIImage animatedImageWithImages:scaledImages duration:image.duration];
    }
    else {
        if ([[UIScreen mainScreen] respondsToSelector:@selector(scale)]) {
            CGFloat scale = 1.0;
            if (key.length >= 8) {
                // Search @2x. at the end of the string, before a 3 to 4 extension length (only if key len is 8 or more @2x. + 4 len ext)
                NSRange range = [key rangeOfString:@"@2x." options:0 range:NSMakeRange(key.length - 8, 5)];
                if (range.location != NSNotFound) {
                    scale = 2.0;
                }
            }

            UIImage *scaledImage = [[UIImage alloc] initWithCGImage:image.CGImage scale:scale orientation:image.imageOrientation];
            image = scaledImage;
        }
        return image;
    }
}