CODEWITHSUNDEEP
iosimagemetadata
Hardik Shah
Hardik Shah

Reputation: 183

How to get image metadata in ios

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.

Upvotes: 17

Views: 27354

Answers (10)

Jonas Schnelli
Jonas Schnelli

Reputation: 10005

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.

Upvotes: 30

Hassaan Fayyaz
Hassaan Fayyaz

Reputation: 209

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 is the list of all dictionary keys extracted

Here are some sample dictionary values such as FocalLength, ApertureValue, LensSpecification etc enter image description here

LensModel, ShutterSpeedValue etc details

Upvotes: 0

Ralf Ebert
Ralf Ebert

Reputation: 4082

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 }

}

Upvotes: 2

shanezzar
shanezzar

Reputation: 1170

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;
    }
}];

Upvotes: 1

Berlin
Berlin

Reputation: 2227

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).

Upvotes: 0

kurtanamo
kurtanamo

Reputation: 1828

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
  }

Upvotes: 5

Usman Nisar
Usman Nisar

Reputation: 3081

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]

Upvotes: 14

Satyanarayana
Satyanarayana

Reputation: 1067

-(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
    }];
}

Upvotes: 0

Chris Prince
Chris Prince

Reputation: 7574

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;
    };
}
*/

Upvotes: 0

Gaurav Taywade
Gaurav Taywade

Reputation: 8347

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

Upvotes: -2

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