62 lines
2.1 KiB
Swift
62 lines
2.1 KiB
Swift
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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func scaleAndCropImage(_ img: UIImage, _ size: CGSize) -> UIImage? {
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let aspect = img.size.width / img.size.height
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let targetAspect = size.width / size.height
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var newWidth: CGFloat
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var newHeight: CGFloat
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if aspect < targetAspect {
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newWidth = size.width
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newHeight = size.width / aspect
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} else {
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newHeight = size.height
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newWidth = size.height * aspect
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}
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UIGraphicsBeginImageContextWithOptions(size, false, 0.0)
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img.draw(in: CGRect(x: (size.width - newWidth) / 2, y: (size.height - newHeight) / 2, width: newWidth, height: newHeight))
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let newImage = UIGraphicsGetImageFromCurrentImageContext()
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UIGraphicsEndImageContext()
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return newImage
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}
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