UIImage 加载七牛图片，Retina 支持

qiniu-afnetworking.m

#import "UIImageView+Qiniu.h"
#import <UIImageView+AFNetworking.h>

@implementation UIImageView (Qiniu)

- (void)qiniu_setImageWithURL:(NSURL *)url {
    NSURLComponents *components = [[NSURLComponents alloc] initWithURL:url resolvingAgainstBaseURL:NO];

    CGFloat scale = [[UIScreen mainScreen] scale];

    CGSize size = self.frame.size;

    NSString *query = [NSString stringWithFormat:@"imageView2/2/w/%1.0f/h/%1.0f/format/JPG", size.width * scale, size.height * scale];
    [components setQuery:query];

    NSLog(@"Loading image: %@", [components URL]);

    [self setImageWithURL:[components URL]];
}

@end