convert_heic02.swift

import Foundation
import AppKit
import AVFoundation

extension NSImage {
    @objc var CGImage: CGImage? {
        get {
            guard let imageData = self.tiffRepresentation else { return nil }
            guard let sourceData = CGImageSourceCreateWithData(imageData as CFData, nil) else { return nil }
            return CGImageSourceCreateImageAtIndex(sourceData, 0, nil)
        }
    }
}

let output = "wallpapers-new/output.heic"
let quality = 0.9
var imageData: Data? = nil

if let dir = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first {

    let destinationData = NSMutableData()
    if let destination = CGImageDestinationCreateWithData(destinationData, AVFileType.heic as CFString, 16, nil) {
        let options = [kCGImageDestinationLossyCompressionQuality: quality]

        for index in 1...16 {
            let fileURL = dir.appendingPathComponent("wallpapers-new/\(index).png")
            let orginalImage = NSImage(contentsOf: fileURL)

            if let cgImage = orginalImage?.CGImage {

                if index == 1 {
                    let imageMetadata = CGImageMetadataCreateMutable()

                    let imageMetadataTag = CGImageMetadataTagCreate("http://ns.apple.com/namespace/1.0/" as CFString, 
                                                                    "apple_desktop" as CFString, 
                                                                    "solar" as CFString, 
                                                                    CGImageMetadataType.string, 
                                                                    "YnBsaXN0MDDRAQJSc2mvEBADDBAUGBwgJCgsMDQ4PEFF1AQFB" +
                                                                    "gcICQoLUWlRelFhUW8QACNAcO7vOubr3yO/1e+pmkOtXBAB1A" +
                                                                    "QFBgcNDg8LEAEjQFRxqCKOFiAjwCR6waUkDgHUBAUGBxESEws" +
                                                                    "QAiNAVZV4BI4c+CPAEP2uFrMcrdQEBQYHFRYXCxADI0BWtALK" +
                                                                    "mrjwIz/2ObLnx6l21AQFBgcZGhsLEAQjQFfTrJlEjnwjQByrL" +
                                                                    "le1Q0rUBAUGBx0eHwsQBSNAWPrrmI0ISCNAKiwhpSRpc9QEBQ" +
                                                                    "YHISIjCxAGI0BgJff9KDpyI0BENTOsilht1AQFBgclJicLEAc" +
                                                                    "jQGbHdYIVQKojQEq3fAg86lXUBAUGBykqKwsQCCNAbTGmpC2Y" +
                                                                    "RiNAQ2WFOZGjntQEBQYHLS4vCxAJI0BwXfII2B+SI0AmLcjfu" +
                                                                    "C7g1AQFBgcxMjMLEAojQHCnF6YrsxcjQBS9AVBLTq3UBAUGBz" +
                                                                    "U2NwsQCyNAcTcSnimmjCPAGP5E0ASXJtQEBQYHOTo7CxAMI0B" +
                                                                    "xgSADjxK2I8AoalieOTyE1AQFBgc9Pj9AEA0jQHNWsnnMcWIj" +
                                                                    "wEO+oq1pXr8QANQEBQYHQkNEQBAOI0ABZpkFpAcAI8BKYGg/V" +
                                                                    "vMf1AQFBgdGR0hAEA8jQErBKblRzPgjwEMGElBIUO0ACAALAA" +
                                                                    "4AIQAqACwALgAwADIANAA9AEYASABRAFMAXABlAG4AcAB5AII" +
                                                                    "AiwCNAJYAnwCoAKoAswC8AMUAxwDQANkA4gDkAO0A9gD/AQEB" +
                                                                    "CgETARwBHgEnATABOQE7AUQBTQFWAVgBYQFqAXMBdQF+AYcBk" +
                                                                    "AGSAZsBpAGtAa8BuAHBAcMBzAHOAdcB4AHpAesB9AAAAAAAAA" +
                                                                    "IBAAAAAAAAAEkAAAAAAAAAAAAAAAAAAAH9" as CFTypeRef)

                    let success = CGImageMetadataSetTagWithPath(imageMetadata, nil, "xmp:solar" as CFString, imageMetadataTag!)
                    if !success {
                        print("Error!!!")
                    }

                    CGImageDestinationAddImageAndMetadata(destination, cgImage, imageMetadata, options as CFDictionary)

                } else {
                    CGImageDestinationAddImage(destination, cgImage, options as CFDictionary)
                }
            }
        }

        CGImageDestinationFinalize(destination)
        imageData = destinationData as Data

        let outputURL = dir.appendingPathComponent(output)
        try! imageData?.write(to: outputURL)
    }
}

Great work! Are you still planing to release an App?