Write image metadata to JPG/PNG file in iOS

Question

Is there any way to write a UIImage to a JPG/PNG file and then append metadata to it? I know you can use:

writeImageDataToSavedPhotosAlbum:metadata:completionBlock

to do this in the Saved Photos, but how do you do the same thing directly to a file? I can't seem to find any way to do this. I know that UIImagePNGRepresentation() and UIImageJPGRepresentation() will give you NSData that you can use to write the file, but there's no way to append/replace the metadata in the file.

Any ideas?

Perhaps this answer to a similar question will help: http://stackoverflow.com/questions/5125323/problem-setting-exif-data-for-an-image/5294574#5294574 — Greg, Mar 16 '11 at 19:50
Writing a custom PNG exporter is a matter of 3 days, anyway :) — Sulthan, Nov 01 '11 at 16:40
You should take a look at ImageIO framework for that. You can add metadata to `CGImageDestination` using `CGImageDestinationSetProperties` and then get the raw data from it — Voda Ion, Sep 24 '13 at 14:14

score 3 · Answer 1 · edited May 23 '17 at 11:51

3

Looks like a duplicate.

To add metadata to a UIImage you can use the ImageIO framework You can create a CGImageDestination object from a UIImage, add metadata to it using CGImageDestinationSetProperties and then get the raw data (which includes the compressed image and the metadata) from it.

edited May 23 '17 at 11:51

Community

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answered Aug 08 '13 at 14:03

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score -7 · Answer 2 · answered Feb 03 '12 at 09:04

@rekle Check it out this code is for writing the photo in to file

NSData *imageData = UIImagePNGRepresentation(self.imageView.image);
            NSData *myImage=[[NSData alloc]initWithData:imageData];
            NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
            NSString *documentsDirectory = [paths objectAtIndex:0];
            NSLog(@"%@",documentsDirectory);

            NSString *fullPathToFile = [documentsDirectory stringByAppendingPathComponent:[NSString stringWithFormat:@"%@.png",camtitle.text]];
            [myImage writeToFile:fullPathToFile atomically:YES];
            NSLog(@"%@",fullPathToFile);
            [myImage release

];

This does not address the question of how to add metadata to the file — Juan Carlos Méndez, Jun 22 '12 at 04:01

Write image metadata to JPG/PNG file in iOS

2 Answers2