小编Gre*_*Ree的帖子

我无法理解为什么metaDic总是为空.有一个代码.

    CFDataRef dataRef = CGDataProviderCopyData(CGImageGetDataProvider(img.CGImage)); //(UIImage *img)
    CGImageSourceRef mySourceRef =  CGImageSourceCreateWithData(dataRef, NULL);
    NSDictionary *metaDic = (NSDictionary *) CGImageSourceCopyPropertiesAtIndex(mySourceRef,0,NULL);
    NSDictionary *tiffDic = (NSDictionary *)[metaDic objectForKey:(NSString *)kCGImagePropertyTIFFDictionary];
    NSString *AuthorName  =  [tiffDic objectForKey:(NSString *)kCGImagePropertyTIFFArtist];

我做了一些获取图片的变种.在这里我发现了:

获取信息的一种方式 - 我需要从网站上获取它,并在那里得到我的信息:

              //  NSURL *UrlPath  - path of picture    image.jpg   from web site
            NSData *dataImg = [NSData dataWithContentsOfURL:UrlPath];

            CGImageSourceRef mySource =  CGImageSourceCreateWithData((CFDataRef)dataImg, NULL); 
            NSDictionary *metaDic = (NSDictionary *) CGImageSourceCopyPropertiesAtIndex(mySource,0,NULL);
            NSDictionary *tiffDic = [metaDic objectForKey:(NSString *)kCGImagePropertyTIFFDictionary];

            /// Log of tiffDic    
tiffDic = {
Artist =(
  "mr. Smith"
  ); …