tauri-plugins-workspace/plugins/camera/ios/Sources/CameraExtensions.swift

// Copyright 2019-2023 Tauri Programme within The Commons Conservancy
// SPDX-License-Identifier: Apache-2.0
// SPDX-License-Identifier: MIT

import Photos
import UIKit

internal protocol CameraAuthorizationState {
  var authorizationState: String { get }
}

extension AVAuthorizationStatus: CameraAuthorizationState {
  var authorizationState: String {
    switch self {
    case .denied, .restricted:
      return "denied"
    case .authorized:
      return "granted"
    case .notDetermined:
      fallthrough
    @unknown default:
      return "prompt"
    }
  }
}

extension PHAuthorizationStatus: CameraAuthorizationState {
  var authorizationState: String {
    switch self {
    case .denied, .restricted:
      return "denied"
    case .authorized:
      return "granted"
    #if swift(>=5.3)
      // poor proxy for Xcode 12/iOS 14, should be removed once building with Xcode 12 is required
      case .limited:
        return "limited"
    #endif
    case .notDetermined:
      fallthrough
    @unknown default:
      return "prompt"
    }
  }
}

extension PHAsset {
  /**
     Retrieves the image metadata for the asset.
     */
  var imageData: [String: Any] {
    let options = PHImageRequestOptions()
    options.isSynchronous = true
    options.resizeMode = .none
    options.isNetworkAccessAllowed = false
    options.version = .current

    var result: [String: Any] = [:]
    _ = PHCachingImageManager().requestImageDataAndOrientation(for: self, options: options) {
      (data, _, _, _) in
      if let data = data as NSData? {
        let options = [kCGImageSourceShouldCache as String: kCFBooleanFalse] as CFDictionary
        if let imgSrc = CGImageSourceCreateWithData(data, options),
          let metadata = CGImageSourceCopyPropertiesAtIndex(imgSrc, 0, options) as? [String: Any]
        {
          result = metadata
        }
      }
    }
    return result
  }
}

extension UIImage {
  /**
     Generates a new image from the existing one, implicitly resetting any orientation.
     Dimensions greater than 0 will resize the image while preserving the aspect ratio.
     */
  func reformat(to size: CGSize? = nil) -> UIImage {
    let imageHeight = self.size.height
    let imageWidth = self.size.width
    // determine the max dimensions, 0 is treated as 'no restriction'
    var maxWidth: CGFloat
    if let size = size, size.width > 0 {
      maxWidth = size.width
    } else {
      maxWidth = imageWidth
    }
    let maxHeight: CGFloat
    if let size = size, size.height > 0 {
      maxHeight = size.height
    } else {
      maxHeight = imageHeight
    }
    // adjust to preserve aspect ratio
    var targetWidth = min(imageWidth, maxWidth)
    var targetHeight = (imageHeight * targetWidth) / imageWidth
    if targetHeight > maxHeight {
      targetWidth = (imageWidth * maxHeight) / imageHeight
      targetHeight = maxHeight
    }
    // generate the new image and return
    let format: UIGraphicsImageRendererFormat = UIGraphicsImageRendererFormat.default()
    format.scale = 1.0
    format.opaque = false
    let renderer = UIGraphicsImageRenderer(
      size: CGSize(width: targetWidth, height: targetHeight), format: format)
    return renderer.image { (_) in
      self.draw(in: CGRect(origin: .zero, size: CGSize(width: targetWidth, height: targetHeight)))
    }
  }
}