담는 도구가 된 카메라, 그리고 사진 한 장의 값

import SwiftUI
import UIKit
import UniformTypeIdentifiers

enum CaptureResult {
    case photo(UIImage)
    case movie(URL)
}

/// The system camera: flash, lens switch, focus and shutter the person already knows.
/// Policy stays with the caller; this view never dismisses itself.
struct CameraCapture: UIViewControllerRepresentable {
    var allowsVideo = false
    let onCapture: (CaptureResult?) -> Void   // nil means cancelled

    func makeUIViewController(context: Context) -> UIImagePickerController {
        let picker = UIImagePickerController()
        // A simulator has no camera: fall back to the library instead of crashing.
        picker.sourceType = UIImagePickerController.isSourceTypeAvailable(.camera) ? .camera : .photoLibrary
        picker.mediaTypes = allowsVideo ? [UTType.image.identifier, UTType.movie.identifier] : [UTType.image.identifier]
        picker.delegate = context.coordinator
        return picker
    }

    func updateUIViewController(_ controller: UIImagePickerController, context: Context) {}

    func makeCoordinator() -> Coordinator { Coordinator(onCapture: onCapture) }

    @MainActor
    final class Coordinator: NSObject, UIImagePickerControllerDelegate, UINavigationControllerDelegate {
        let onCapture: (CaptureResult?) -> Void
        init(onCapture: @escaping (CaptureResult?) -> Void) { self.onCapture = onCapture }

        func imagePickerController(_ picker: UIImagePickerController,
                                   didFinishPickingMediaWithInfo info: [UIImagePickerController.InfoKey: Any]) {
            if let url = info[.mediaURL] as? URL {
                onCapture(.movie(url))
            } else if let image = info[.originalImage] as? UIImage {
                onCapture(.photo(image))
            } else {
                onCapture(nil)
            }
        }

        func imagePickerControllerDidCancel(_ picker: UIImagePickerController) { onCapture(nil) }
    }
}

extension ImageDownscale {
    /// Re-encoding strips EXIF, including location. That is the point, not a side effect.
    static func jpegData(_ image: UIImage, quality: CGFloat = 0.85) -> Data? {
        let size = targetSize(for: image.size)
        let format = UIGraphicsImageRendererFormat.default()
        format.scale = 1
        let resized = UIGraphicsImageRenderer(size: size, format: format).image { _ in
            image.draw(in: CGRect(origin: .zero, size: size))
        }
        return resized.jpegData(compressionQuality: quality)
    }
}

import CoreGraphics

enum ImageDownscale {
    /// The long edge a photo leaves the phone with. Never enlarges.
    static let longEdge: CGFloat = 2048

    static func targetSize(for size: CGSize, longEdge: CGFloat = longEdge) -> CGSize {
        let longest = max(size.width, size.height)
        guard longest > longEdge, longest > 0 else { return size }
        let scale = longEdge / longest
        return CGSize(width: (size.width * scale).rounded(), height: (size.height * scale).rounded())
    }
}

// targetSize(for: 4032 x 3024) -> 2048 x 1536
// targetSize(for: 3024 x 4032) -> 1536 x 2048
// targetSize(for: 1200 x 900)  -> 1200 x 900   (never enlarged)