73 lines
2.7 KiB
Swift
73 lines
2.7 KiB
Swift
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import Foundation
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import UIKit
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final class FileProcessing {
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static let shared = FileProcessing()
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static var fileFolder: URL {
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// swiftlint:disable:next force_unwrapping
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let documentsURL = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first!
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return documentsURL.appendingPathComponent(Const.fileFolder)
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}
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func createThumbnail(id: String, localUrl: URL) -> URL? {
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// make path for thumbnail
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let thumbnailUrl = FileProcessing.fileFolder.appendingPathComponent(id).appendingPathExtension("png")
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// check if thumbnail already exists
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if FileManager.default.fileExists(atPath: thumbnailUrl.path) {
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return thumbnailUrl
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}
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// create thumbnail if not exists
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switch localUrl.lastPathComponent.attachmentType {
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case .image:
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guard let image = UIImage(contentsOfFile: localUrl.path) else { return nil }
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let targetSize = CGSize(width: Const.attachmentPreviewSize, height: Const.attachmentPreviewSize)
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guard let thumbnail = scaleAndCropImage(image, targetSize) else { return nil }
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guard let data = thumbnail.pngData() else { return nil }
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do {
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try data.write(to: thumbnailUrl)
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return thumbnailUrl
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} catch {
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return nil
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}
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default:
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return nil
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}
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}
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}
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private extension FileProcessing {
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func scaleAndCropImage(_ img: UIImage, _ size: CGSize) -> UIImage? {
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guard let cgImage = img.cgImage else {
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return nil
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}
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let contextImage: UIImage = .init(cgImage: cgImage)
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var contextSize: CGSize = contextImage.size
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var posX: CGFloat = 0.0
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var posY: CGFloat = 0.0
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let cgwidth: CGFloat = size.width
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let cgheight: CGFloat = size.height
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// Check and handle if the image is wider than the requested size
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if contextSize.width > contextSize.height {
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posX = ((contextSize.width - contextSize.height) / 2)
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contextSize.width = contextSize.height
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} else if contextSize.width < contextSize.height {
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// Check and handle if the image is taller than the requested size
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posY = ((contextSize.height - contextSize.width) / 2)
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contextSize.height = contextSize.width
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}
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let rect: CGRect = .init(x: posX, y: posY, width: cgwidth, height: cgheight)
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guard let contextCg = contextImage.cgImage, let imgRef = contextCg.cropping(to: rect) else {
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return nil
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}
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let image: UIImage = .init(cgImage: imgRef, scale: img.scale, orientation: img.imageOrientation)
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return image
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}
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}
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