UIImage+SDWebImageAnimatedGifSwizzle.h

#import <UIKit/UIKit.h>

@interface UIImage (SDWebImageAnimatedGifSwizzle)

@end

UIImage+SDWebImageAnimatedGifSwizzle.m

//
//  UIImage+SDWebImageAnimatedGifSwizzle.m
//
//  Created by Philip Dow on 8/26/15.
//  Just Use It License
//

#import "UIImage+SDWebImageAnimatedGifSwizzle.h"
#import <SDWebImage/UIImage+MultiFormat.h>
#import <SDWebImage/UIImage+GIF.h>
#import <objc/runtime.h>

// In case you need a refresher: http://nshipster.com/method-swizzling/
// Swizzling + (UIImage *)sd_animatedGIFWithData:(NSData *)data;
// to return an unanimated image

@interface UIImage (SDWebImageAnimatedGifSwizzleExtern)

+ (UIImageOrientation)sd_imageOrientationFromImageData:(NSData *)imageData;

@end

#pragma mark -

@implementation UIImage (SDWebImageAnimatedGifSwizzle)

+ (void)load
{
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        // Class class = [self class];
        Class class = object_getClass((id)self);

        SEL originalSelector = @selector(sd_animatedGIFWithData:);
        SEL swizzledSelector = @selector(sd_swizzle_animatedGIFWithData:);

        // Method originalMethod = class_getInstanceMethod(class, originalSelector);
        // Method swizzledMethod = class_getInstanceMethod(class, swizzledSelector);
        
        Method originalMethod = class_getClassMethod(class, originalSelector);
        Method swizzledMethod = class_getClassMethod(class, swizzledSelector);

        // When swizzling a class method, use the following:
        // Class class = object_getClass((id)self);
        // ...
        // Method originalMethod = class_getClassMethod(class, originalSelector);
        // Method swizzledMethod = class_getClassMethod(class, swizzledSelector);

        BOOL didAddMethod =
            class_addMethod(class,
                originalSelector,
                method_getImplementation(swizzledMethod),
                method_getTypeEncoding(swizzledMethod));

        if (didAddMethod) {
            class_replaceMethod(class,
                swizzledSelector,
                method_getImplementation(originalMethod),
                method_getTypeEncoding(originalMethod));
        } else {
            method_exchangeImplementations(originalMethod, swizzledMethod);
        }
    });
}

+ (UIImage*) sd_swizzle_animatedGIFWithData:(NSData*)data
{
    UIImage *image = [[UIImage alloc] initWithData:data];
    UIImageOrientation orientation = [self sd_imageOrientationFromImageData:data];
    if (orientation != UIImageOrientationUp) {
        image = [UIImage imageWithCGImage:image.CGImage scale:image.scale orientation:orientation];
    }
    return image;
}

@end