Re: Getting NSDate from EXIF of a image
Re: Getting NSDate from EXIF of a image
- Subject: Re: Getting NSDate from EXIF of a image
- From: Jushin <email@hidden>
- Date: Mon, 2 Mar 2009 23:48:23 -0500
I found that in order to convert NSString format of date to NSDate, we
need timezone.
But, EXIF doesn't support timezone unless GPS tags exist.
So, here is what I have come up with:
NSDictionary *metadata = (NSDictionary *)
CGImageSourceCopyPropertiesAtIndex(source, 0, NULL);
NSMutableDictionary *muMetadata = [[metadata mutableCopy] autorelease];
[metadata release];
NSMutableDictionary *EXIFDictionary = [[[muMetadata
objectForKey:(NSString *)kCGImagePropertyExifDictionary]
mutableCopy] autorelease];
NSString *EXIFDate = [[EXIFDictionary objectForKey:(NSString
*)kCGImagePropertyExifDateTimeDigitized] retain];
NSArray *listItems = [EXIFDate componentsSeparatedByString:@":"];
NSString *newFormatedDate = [NSString stringWithFormat:@"%@-%@-%@:%@:%@ %d",
[listItems objectAtIndex:0], [listItems objectAtIndex:1],
[listItems objectAtIndex:2],
[listItems objectAtIndex:3], [listItems objectAtIndex:4],
(([[NSTimeZone systemTimeZone] secondsFromGMT]/60)/60)];
NSDate *aDate = [[NSDate alloc] initWithString:newFormatedDate];
I still think these are not clever way. If you have better idea,
please share it with me :)
On Mon, Mar 2, 2009 at 10:00 PM, Jushin <email@hidden> wrote:
> I need to get time and date from EXIF of a image.
> Following is the code snippet I used:
>
> NSDictionary *metadata = (NSDictionary *)
> CGImageSourceCopyPropertiesAtIndex(source, 0, NULL);
> NSMutableDictionary *muMetadata = [[metadata mutableCopy] autorelease];
> [metadata release];
>
> NSMutableDictionary *EXIFDictionary = [[[muMetadata
> objectForKey:(NSString *)kCGImagePropertyExifDictionary]
> mutableCopy] autorelease];
>
> NSString *EXIFDate = [[EXIFDictionary objectForKey:(NSString
> *)kCGImagePropertyExifDateTimeDigitized] retain];
> NSLog(EXIFDate);
>
> NSDate *aDate = [[NSDate alloc] initWithString: EXIFDate];
>
>
> Here are my questions:
>
> 1. the last line, NSDate *aDate returns null.
> I think it is because the format of EXIFDate string that was created
> right above isn't correct.
> When I did NSLog(EXIFDate), I get followings:
> 2008:11:06 19:12:51
>
> According to the NSDate documentation, string format of time should be:
> 2008-11-06 19:12:51
>
> 2. the returned date string (EXIFData) doesn't have timezone information.
> Is it possible to get timezone info as well from the EXIF information?
>
> 3. Well... eventually what I want to do is, I want to create "unix
> time" format of date from image EXIF using timeIntervalSince1970.
> Is there any other better way to get this?
>
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