Write XMP

Writer.swift

import UIKit
import CoreServices
import ImageIO

class Writer {

    let output = NSTemporaryDirectory().appending("output.heic")
    lazy var outputUrl: CFURL = {
        return URL(fileURLWithPath: output) as CFURL
    }()

    /// The plist to encode
    let plist = "123"

    func run() {
        
        if let file = Bundle.main.url(forResource: "test", withExtension: "heic"),
            let data = try? Data(contentsOf: file) as CFData,
            let source = CGImageSourceCreateWithData(data, nil) {
            
            // Get the UTI for the image (maybe we should harcode this as public.heic)
            let uti = CGImageSourceGetType(source)!
        
            // Get the count of image source
            let count = CGImageSourceGetCount(source)
            
            // Create the destination
            let destination = CGImageDestinationCreateWithURL(outputUrl, uti, count, nil)!
    

            // Create the new XMP metadata
            let toWrite = "<x:xmpmeta xmlns:x=\"adobe:ns:meta/\" x:xmptk=\"XMP Core 5.4.0\"><rdf:RDF xmlns:rdf=\"http://www.w3.org/1999/02/22-rdf-syntax-ns#\"><rdf:Description rdf:about=\"\" xmlns:apple_desktop=\"http://ns.apple.com/namespace/1.0/\"><apple_desktop:solar>\(plist)</apple_desktop:solar></rdf:Description></rdf:RDF></x:xmpmeta>"
            
            let newData = toWrite.data(using: .ascii)! as CFData
            let meta = CGImageMetadataCreateFromXMPData(newData)!
            
            // Set the options to include metadata
            let destOptions: [String: AnyObject] = [
                kCGImageDestinationMergeMetadata as String: NSNumber(value: false),
                kCGImageDestinationMetadata as String: meta
            ]
            
            var error: Unmanaged<CFError>?
            withUnsafeMutablePointer(to: &error) { (ptr) in
                CGImageDestinationCopyImageSource(destination, source, destOptions as CFDictionary, ptr)
            }
            
            print("ERROR: ", error)
            
            CGImageDestinationFinalize(destination)
            
        }
        
    }
    

}

let writer = Writer()
writer.run()