Kurdtvs-Live-Kurdish-TV-Kur.../Mastodon/Vender/PHPickerResultLoader.swift

73 lines
2.7 KiB
Swift

//
// PHPickerResultLoader.swift
// Mastodon
//
// Created by MainasuK Cirno on 2021-3-18.
//
import os.log
import Foundation
import Combine
import MobileCoreServices
import PhotosUI
// load image with low memory usage
// Refs: https://christianselig.com/2020/09/phpickerviewcontroller-efficiently/
enum PHPickerResultLoader {
static func loadImageData(from result: PHPickerResult) -> Future<Data?, Error> {
Future { promise in
result.itemProvider.loadFileRepresentation(forTypeIdentifier: UTType.image.identifier) { url, error in
if let error = error {
promise(.failure(error))
return
}
guard let url = url else {
promise(.success(nil))
return
}
let sourceOptions = [kCGImageSourceShouldCache: false] as CFDictionary
guard let source = CGImageSourceCreateWithURL(url as CFURL, sourceOptions) else {
return
}
let downsampleOptions = [
kCGImageSourceCreateThumbnailFromImageAlways: true,
kCGImageSourceCreateThumbnailWithTransform: true,
kCGImageSourceThumbnailMaxPixelSize: 4096,
] as CFDictionary
guard let cgImage = CGImageSourceCreateThumbnailAtIndex(source, 0, downsampleOptions) else {
return
}
let data = NSMutableData()
guard let imageDestination = CGImageDestinationCreateWithData(data, kUTTypeJPEG, 1, nil) else {
promise(.success(nil))
return
}
let isPNG: Bool = {
guard let utType = cgImage.utType else { return false }
return (utType as String) == UTType.png.identifier
}()
let destinationProperties = [
kCGImageDestinationLossyCompressionQuality: isPNG ? 1.0 : 0.75
] as CFDictionary
CGImageDestinationAddImage(imageDestination, cgImage, destinationProperties)
CGImageDestinationFinalize(imageDestination)
let dataSize = ByteCountFormatter.string(fromByteCount: Int64(data.length), countStyle: .memory)
os_log(.info, log: .debug, "%{public}s[%{public}ld], %{public}s: load image %s", ((#file as NSString).lastPathComponent), #line, #function, dataSize)
promise(.success(data as Data))
}
}
}
}