How to get image metadata in ios

Question

I want to display image metadata using ios. Meta data like Aperture, Shutterspeed, Exposure Compensation, ISO, Lens Focal Length, etc. So please help me if anybody has idea.

what do u mean by image metadata (Name, size and some others)? Please elaborate... — Pranav Jaiswal, Sep 18 '12 at 14:01

score 29 · Accepted Answer · edited Jul 31 '23 at 11:30

29

CGImageSourceRef source = CGImageSourceCreateWithURL( (CFURLRef) aUrl, NULL);
CGImageSourceRef source = CGImageSourceCreateWithData( (CFDataRef) theData, NULL);
NSDictionary* metadata = (NSDictionary *)CFBridgingRelease(CGImageSourceCopyPropertiesAtIndex(source,0,NULL));
CFRelease(source);

Check the dictionary contents here.

edited Jul 31 '23 at 11:30

Benny K

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answered Sep 18 '12 at 14:13

Jonas Schnelli

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Thanks Jonas Schnelli. It's help me a lot. Thanks buddy. – Hardik Shah Sep 19 '12 at 06:31
4

Of course, you should mention that you will have to add #import to your header in order to use the class... – jesses.co.tt Oct 08 '13 at 23:40
1

If you're using ARC, split it up like so to avoid memory leaks `CFDictionaryRef dictRef = CGImageSourceCopyPropertiesAtIndex(source,0,NULL); NSDictionary* metadata = (__bridge NSDictionary *)dictRef; CFRelease(source); CFRelease(dictRef);` – Drew H Aug 24 '14 at 06:09

score 14 · Answer 2 · edited Dec 10 '17 at 05:59

14

Here is code, to get meta data from an image path:

NSData *imagedata = [NSData dataWithContentsOfFile:imagePath];
CGImageSourceRef source = CGImageSourceCreateWithData((CFMutableDataRef)imagedata, NULL);
NSDictionary *metadata = [(NSDictionary *)CGImageSourceCopyPropertiesAtIndex(source,0,NULL)autorelease];

Or, if using swift 4.0:

var imagedata = Data(contentsOfFile: imagePath) 
var source: CGImageSourceRef = CGImageSourceCreateWithData((imagedata as? CFMutableDataRef), nil) 
var metadata = CGImageSourceCopyPropertiesAtIndex(source, 0, nil) as? [AnyHashable: Any]

edited Dec 10 '17 at 05:59

justinpawela

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answered Nov 25 '13 at 06:46

Usman Nisar

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how to do that in swift3 or swift4? – Saurabh Prajapati Nov 10 '17 at 04:10
1

var imagedata = Data(contentsOfFile: imagePath) var source: CGImageSourceRef = CGImageSourceCreateWithData((imagedata as? CFMutableDataRef), nil) var metadata = CGImageSourceCopyPropertiesAtIndex(source, 0, nil) as? [AnyHashable: Any] – Usman Nisar Nov 10 '17 at 10:20
hope it helps you – Usman Nisar Nov 10 '17 at 10:20
Yes! i have also tried same way and is working!I think you need to update this in your answer – Saurabh Prajapati Nov 10 '17 at 11:00
Sorry to bump this after such a long while, but - Benchmarking shows that reading the metadata thus, depends on the size of the image (which shouldn't be the case since the metadata is merely some ~fixed prefix of the `Data`). Is there something I'm missing? Specifically reading the metadata of a 50KiB image takes 50ns, but reading a 1.7MiB image takes 800ns (same as `UIImage(data:)`). – Benny K Jul 23 '23 at 15:47

score 5 · Answer 3 · answered Dec 12 '17 at 14:09

swift 4

static func imageDataProperties(_ imageData: Data) -> NSDictionary? {
    if let imageSource = CGImageSourceCreateWithData(imageData as CFData, nil)
    {
      if let dictionary = CGImageSourceCopyPropertiesAtIndex(imageSource, 0, nil) {
        return dictionary
      }
    }
    return nil
  }

score 2 · Answer 4 · answered Oct 16 '19 at 13:45

Reading image properties via Core Graphics wrapped as Swift struct:

struct ImageMetadata {

    var imageProperties : [CFString: Any]

    init?(data: Data) {
        let options = [kCGImageSourceShouldCache: kCFBooleanFalse]
        if let imageSource = CGImageSourceCreateWithData(data as CFData, options as CFDictionary),
            let imageProperties = CGImageSourceCopyPropertiesAtIndex(imageSource, 0, nil) as? [CFString: Any] {
            self.imageProperties = imageProperties
        } else {
            return nil
        }
    }

    var dpi : Int? { imageProperties[kCGImagePropertyDPIWidth] as? Int }
    var width : Int? { imageProperties[kCGImagePropertyPixelWidth] as? Int }
    var height : Int? { imageProperties[kCGImagePropertyPixelHeight] as? Int }

}

shanezzar · Answer 5 · 2018-03-07T12:41:59.317

updated to iOS 11 with photos framework

Objective - C:

#import <Photos/Photos.h>

- (void)imagePickerController:(UIImagePickerController *)imagePicker didFinishPickingMediaWithInfo:(NSDictionary<NSString *,id> *)info {

    PHAsset* asset = info[UIImagePickerControllerPHAsset];

    [asset requestContentEditingInputWithOptions:nil completionHandler:^(PHContentEditingInput *contentEditingInput, NSDictionary *info) {
        CIImage *fullImage = [CIImage imageWithContentsOfURL:contentEditingInput.fullSizeImageURL];

        NSLog(@"%@", fullImage.properties.description);
    }];

    [imagePicker dismissViewControllerAnimated:YES completion:nil];
}

You also need the permission of Photo library Usage (NSPhotoLibraryUsageDescription) and then can add the following code to view did load or view did appear

[PHPhotoLibrary requestAuthorization:^(PHAuthorizationStatus status) {
    switch (status) {
        case PHAuthorizationStatusAuthorized:
            NSLog(@"PHAuthorizationStatusAuthorized");
            break;
        case PHAuthorizationStatusDenied:
            NSLog(@"PHAuthorizationStatusDenied");
            break;
        case PHAuthorizationStatusNotDetermined:
            NSLog(@"PHAuthorizationStatusNotDetermined");
            break;
        case PHAuthorizationStatusRestricted:
            NSLog(@"PHAuthorizationStatusRestricted");
            break;
    }
}];

Chris Prince · Answer 6 · 2014-12-10T20:11:35.263

Here is what I'm using to get the image size:

+ (CGSize) sizeOfImage:(NSString *) fileName withPath: (NSURL *) fullDirectoryPath;
{
    NSURL *imageNameWithPath = [NSURL URLWithString:fileName relativeToURL:fullDirectoryPath];

    CGImageSourceRef source = CGImageSourceCreateWithURL( (CFURLRef) imageNameWithPath, NULL);
    if (!source) return CGSizeZero;

    CFDictionaryRef dictRef = CGImageSourceCopyPropertiesAtIndex(source,0,NULL);
    NSDictionary* metadata = (__bridge NSDictionary *)dictRef;
    NSLog(@"metadata= %@", metadata);
    CGSize result = CGSizeZero;
    CGFloat width = [metadata[@"PixelWidth"] floatValue];
    CGFloat height = [metadata[@"PixelHeight"] floatValue];
    NSLog(@"width= %f, height= %f", width, height);

    // The orientation in the metadata does *not* map to UIImageOrientation. Rather, see: https://developer.apple.com/library/ios/documentation/GraphicsImaging/Reference/CGImageProperties_Reference/index.html#//apple_ref/doc/constant_group/Individual_Image_Properties
    // This idea of orientation seems a little odd to me, but it seems it translates to even numbers need to be switched in width/height, odd numbers do not.
    NSUInteger orientation = [metadata[@"Orientation"] integerValue];

    switch (orientation) {
        // Comments give "Location of the origin of the image"
        case 1: // Top, left
        case 3: // Bottom, right
        case 5: // Left, top
        case 7: // Right, bottom
            result = CGSizeMake(width, height);
            break;

        case 2: // Top, right
        case 4: // Bottom, left
        case 6: // Right, top
        case 8: // Left, bottom
            result = CGSizeMake(height, width);
            break;

        default:
            NSAssert(NO, @"Should not get to here!");
            break;
    }

    CFRelease(source);
    NSLog(@"size: %@, orientation: %d", NSStringFromCGSize(result), orientation);

    return result;
}

/* Example meta data:
    ColorModel = RGB;
    Depth = 8;
    Orientation = 6;
    PixelHeight = 1936;
    PixelWidth = 2592;
    "{Exif}" =     {
        ColorSpace = 1;
        PixelXDimension = 2592;
        PixelYDimension = 1936;
    };
    "{JFIF}" =     {
        DensityUnit = 0;
        JFIFVersion =         (
                               1,
                               1
                               );
        XDensity = 1;
        YDensity = 1;
    };
    "{TIFF}" =     {
        Orientation = 6;
    };
}
*/

Satyanarayana · Answer 7 · 2015-07-04T09:34:59.397

0

-(void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info
{
  NSURL *referenceURL = [info objectForKey:UIImagePickerControllerReferenceURL];

    if(referenceURL) {
    ALAssetsLibrary *library = [[ALAssetsLibrary alloc] init];
    [library assetForURL:referenceURL resultBlock:^(ALAsset *asset) {
        ALAssetRepresentation *rep = [asset defaultRepresentation];
        NSDictionary *metadata = rep.metadata;
        NSLog(@"image data %@", metadata);


    } failureBlock:^(NSError *error) {
        // error handling
    }];
}

edited Jul 04 '15 at 09:34

answered Jul 04 '15 at 09:00

Satyanarayana

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It's better giving some explanations in your answer. – Envil Jul 04 '15 at 09:05

score 0 · Answer 8 · answered Feb 28 '18 at 11:08

Answering my own question. The memory-effective and fast way to get a GPS metadata is

let options = [kCGImageSourceShouldCache as String: kCFBooleanFalse]
if let data = NSData(contentsOfURL: url), imgSrc = CGImageSourceCreateWithData(data, options) {
    let metadata = CGImageSourceCopyPropertiesAtIndex(imgSrc, 0, options) as Dictionary
    let gpsData = metadata[kCGImagePropertyGPSDictionary] as? [String : AnyObject]
}

The second option is

if let img = CIImage(contentsOfURL: url), metadata = img.properties(), 
gpsData = metadata[kCGImagePropertyGPSDictionary] as? [String : AnyObject] { … }

it looks nicer in Swift but uses more memory (tested via Profiler).

score 0 · Answer 9 · answered Apr 21 '21 at 19:32

Here is a sample code that helps us in reading the Aperture, Shutterspeed, Exposure Compensation, ISO, Lens, Focal Length etc and converts it into dictionary format.
Consider all the following functions of a single class

guard let imageSource = CGImageSourceCreateWithURL(fileURL as CFURL, nil),
      let metadata = CGImageSourceCopyMetadataAtIndex(imageSource, 0, nil),
      let tags = CGImageMetadataCopyTags(metadata),
      let imageInfo = self.readMetadataTagArr(tagArr: tags) else { return }

Then there are a few helper functions that actually do all the hardwork to extract/convert the data into dictionary format.

    /// Reads the Arrays of tags and convert them into a dictionary of [String: Any]
private static func readMetadataTagArr(tagArr: CFArray) -> [String: Any]? {
    var result = [String: Any]()
    for (_, tag) in (tagArr as NSArray).enumerated() {
        let tagMetadata = tag as! CGImageMetadataTag
        if let cfName = CGImageMetadataTagCopyName(tagMetadata) {
            let name = String(cfName)
            result[name] = self.readMetadataTag(metadataTag: tagMetadata)
        }
    }
    return result
}

    /// convert CGImageMetadataTag to a dictionary of [String: Any]
private static func readMetadataTag(metadataTag: CGImageMetadataTag) -> [String: Any] {
    var result = [String: Any]()
    guard let cfName = CGImageMetadataTagCopyName(metadataTag) else { return result }
    let name = String(cfName)
    let value = CGImageMetadataTagCopyValue(metadataTag)
    
    /// checking the type of `value` object and then performing respective operation on `value`
    if CFGetTypeID(value) == CFStringGetTypeID() {
        let valueStr = String(value as! CFString)
        result[name] = valueStr
    } else if CFGetTypeID(value) == CFDictionaryGetTypeID() {
        let nsDict: NSDictionary = value as! CFDictionary
        result[name] = self.getDictionary(from: nsDict)
    } else if CFGetTypeID(value) == CFArrayGetTypeID() {
        let valueArr: NSArray = value as! CFArray
        for (_, item) in valueArr.enumerated() {
            let tagMetadata = item as! CGImageMetadataTag
            result[name] = self.readMetadataTag(metadataTag: tagMetadata)
        }
    } else {
        // when the data was of some other type
        let descriptionString: CFString = CFCopyDescription(value);
        let str = String(descriptionString)
        result[name] = str
    }
    return result
}

    /// Converting CGImage Metadata dictionary to [String: Any]
private static func getDictionary(from nsDict: NSDictionary) -> [String: Any] {
    var subDictionary = [String: Any]()
    for (key, val) in nsDict {
        guard let key = key as? String else { continue }
        let tempDict: [String: Any] = [key: val]
        if JSONSerialization.isValidJSONObject(tempDict) {
            subDictionary[key] = val
        } else {
            let mData = val as! CGImageMetadataTag
            let tempDict: [String: Any] = [key: self.readMetadataTag(metadataTag: mData)]
            if JSONSerialization.isValidJSONObject(tempDict) {
                subDictionary[key] = tempDict
            }
        }
    }
    return subDictionary
}

Here is the list of all dictionary keys extracted

Here are some sample dictionary values such as FocalLength, ApertureValue, LensSpecification etc

LensModel, ShutterSpeedValue etc

score -2 · Answer 10 · answered Jul 15 '14 at 11:34

You need to use assets library to read exif metadata of image.

#import <AssetsLibrary/AssetsLibrary.h>

And then add following code :

- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info
{
    NSURL *assetURL = [info objectForKey:UIImagePickerControllerReferenceURL];

    ALAssetsLibrary *library = [[ALAssetsLibrary alloc] init];
    __block NSMutableDictionary *imageMetadata = nil;
    [library assetForURL:assetURL
             resultBlock:^(ALAsset *asset)  {
                 NSDictionary *metadata = asset.defaultRepresentation.metadata;
                 imageMetadata = [[NSMutableDictionary alloc] initWithDictionary:metadata];
                 NSLog(@"%@",imageMetadata.description);
             }
            failureBlock:^(NSError *error) {
            }];
}

Hope this will help

How to get image metadata in ios

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