如何在iOS图像元数据(How to get image metadata in ios)

我想用IOS显示图像元数据。 像光圈，Shutterspeed，曝光补偿，ISO，镜头焦距等元数据，请帮助我，如果任何人有想法。

Answer 1:

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

查了字典的内容在这里 。

Answer 2:

下面是代码，从成像路径获取元数据：

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

或者，如果使用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]

Answer 3:

-(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
    }];
}

Answer 4:

更新到iOS 11张照片框架

Objective - C的：

#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];
}

您还需要照片库使用（NSPhotoLibraryUsageDescription）的许可，然后可以添加以下代码来查看并加载或查看并出现

[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;
    }
}];

Answer 5:

下面是我用得到的图像尺寸是什么：

+ (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;
    };
}
*/

Answer 6:

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
  }

Answer 7:

回答我的问题。 内存有效和快速的方式获得GPS的元数据

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]
}

第二个选项是

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

它看起来更好斯威夫特但会占用更多的内存（通过探查测试）。

Answer 8:

您需要使用资产库来读取图像EXIF的元数据。

#import <AssetsLibrary/AssetsLibrary.h>

然后添加以下代码：

- (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) {
            }];
}

希望这将有助于

文章来源: How to get image metadata in ios