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+//
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+// KMImageOptimization.swift
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+// PDF Master
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+//
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+// Created by lizhe on 2023/5/25.
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+//
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+
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+import AppKit
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+import CoreGraphics
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+import CoreImage
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+
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+class KMImageOptimization: NSObject {
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+ static func compressImageLosslessly(image: NSImage, targetSize: CGSize, maxSizeInBytes: Int, targetCompression: CGFloat) -> Data? {
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+ guard let cgImage = image.cgImage(forProposedRect: nil, context: nil, hints: nil) else {
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+ return nil
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+ }
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+
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+ //宽高自适应
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+ let newSize: CGSize
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+ let widthRatio = targetSize.width / image.size.width
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+ let heightRatio = targetSize.height / image.size.height
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+
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+ if widthRatio > heightRatio {
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+ newSize = CGSize(width: targetSize.height * image.size.width / image.size.height, height: targetSize.height)
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+ } else {
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+ newSize = CGSize(width: targetSize.width, height: targetSize.width * image.size.height / image.size.width)
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+ }
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+
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+ let options: [CFString: Any] = [
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+ kCGImageSourceThumbnailMaxPixelSize: max(newSize.width, newSize.height),
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+ kCGImageSourceCreateThumbnailFromImageAlways: true,
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+ kCGImageDestinationLossyCompressionQuality: 1.0
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+ ]
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+
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+ guard var imageData = CFDataCreateMutable(nil, 0) else {
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+ return nil
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+ }
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+
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+ guard let destination = CGImageDestinationCreateWithData(imageData, kUTTypeJPEG, 1, nil) else {
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+ return nil
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+ }
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+
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+ CGImageDestinationAddImage(destination, cgImage, options as CFDictionary)
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+ CGImageDestinationFinalize(destination)
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+
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+ var dataSize = CFDataGetLength(imageData)
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+ let targetSizeInBytes = Int(CGFloat(maxSizeInBytes) * targetCompression)
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+
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+ if dataSize <= targetSizeInBytes {
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+ return imageData as Data
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+ }
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+
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+ var compressedData: Data?
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+
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+ let optionsLow: [CFString: Any] = [
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+ kCGImageSourceThumbnailMaxPixelSize: max(newSize.width, newSize.height) / 2,
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+ kCGImageSourceCreateThumbnailFromImageAlways: true,
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+ kCGImageDestinationLossyCompressionQuality: targetCompression
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+ ]
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+
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+ let optionsHigh: [CFString: Any] = [
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+ kCGImageSourceThumbnailMaxPixelSize: max(newSize.width, newSize.height),
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+ kCGImageSourceCreateThumbnailFromImageAlways: true,
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+ kCGImageDestinationLossyCompressionQuality: targetCompression
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+ ]
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+
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+ while compressedData == nil {
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+ autoreleasepool {
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+ if targetSizeInBytes > 0 {
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+ if dataSize <= targetSizeInBytes {
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+ compressedData = imageData as Data
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+ } else {
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+ let resizedImageData = NSMutableData()
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+
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+ guard let resizedDestination = CGImageDestinationCreateWithData(resizedImageData as CFMutableData, kUTTypeJPEG, 1, nil) else {
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+ return
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+ }
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+
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+ let bitmapInfo = CGImageAlphaInfo.premultipliedLast.rawValue
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+ let contextBounds = CGRect(origin: .zero, size: newSize)
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+
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+ if let context = CGContext(data: nil, width: Int(newSize.width), height: Int(newSize.height), bitsPerComponent: 8, bytesPerRow: 0, space: CGColorSpaceCreateDeviceRGB(), bitmapInfo: bitmapInfo) {
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+ context.interpolationQuality = .high
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+ context.draw(cgImage, in: contextBounds)
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+ let resizedCGImage = context.makeImage()
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+
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+ if let resizedCGImage = resizedCGImage {
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+ CGImageDestinationAddImage(resizedDestination, resizedCGImage, optionsLow as CFDictionary)
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+ CGImageDestinationFinalize(resizedDestination)
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+
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+ imageData = resizedImageData
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+ dataSize = CFDataGetLength(imageData)
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+ } else {
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+ compressedData = imageData as Data
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+ }
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+ }
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+ }
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+ } else {
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+ compressedData = imageData as Data
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+ }
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+ }
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+ }
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+
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+ return compressedData
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+ }
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+
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+ static func needCompressImageLosslessly(image: NSImage, targetSize: CGSize, maxSizeInBytes: Int, targetCompression: CGFloat) -> String {
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+ let kFilePath: NSString = FileManager.default.urls(for: .cachesDirectory, in: .userDomainMask).first!.path + "KMImageOptimizationCache" as NSString
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+ let string: NSString = (kFilePath as String) + "/" + "optimization.png" as NSString
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+ if (!FileManager.default.fileExists(atPath: string.deletingLastPathComponent as String)) {
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+ try?FileManager.default.createDirectory(atPath: string.deletingLastPathComponent as String, withIntermediateDirectories: true, attributes: nil)
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+ }
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+
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+ if (!FileManager.default.fileExists(atPath: string as String)) {
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+ FileManager.default.createFile(atPath: string as String, contents: nil)
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+ }
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+
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+ // 示例用法
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+ if let compressedData = KMImageOptimization.compressImageLosslessly(image: image, targetSize: targetSize, maxSizeInBytes: maxSizeInBytes, targetCompression: targetCompression) {
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+ let saveURL = URL(fileURLWithPath: string as String)//URL(fileURLWithPath: "/path/to/save/compressed_image.png")
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+ do {
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+ try compressedData.write(to: saveURL)
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+ // 图像已成功保存在指定路径中
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+ print("保存图像成功：\(string)")
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+ } catch {
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+ print("保存图像失败：\(error)")
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+ }
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+ }
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+ return string as String
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+ }
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+}
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