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import UIKit
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import Foundation
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import Combine
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// MARK: - 图片缓存管理器
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class ImageCacheManager: ObservableObject {
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static let shared = ImageCacheManager()
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private let cache = NSCache<NSString, UIImage>()
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private let fileManager = FileManager.default
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private let documentsPath: String
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init() {
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// 设置缓存限制
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cache.countLimit = 50 // 限制缓存数量
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cache.totalCostLimit = 50 * 1024 * 1024 // 限制缓存大小（50MB）
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// 获取文档目录路径
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documentsPath = NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true)[0]
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// 监听内存警告
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NotificationCenter.default.addObserver(
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self,
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selector: #selector(handleMemoryWarning),
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name: UIApplication.didReceiveMemoryWarningNotification,
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object: nil
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)
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}
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deinit {
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NotificationCenter.default.removeObserver(self)
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}
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// MARK: - 内存缓存管理
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/// 设置图片到内存缓存
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func setImage(_ image: UIImage, forKey key: String) {
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cache.setObject(image, forKey: key as NSString)
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}
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/// 从内存缓存获取图片
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func getImage(forKey key: String) -> UIImage? {
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return cache.object(forKey: key as NSString)
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}
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/// 从内存缓存移除图片
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func removeImage(forKey key: String) {
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cache.removeObject(forKey: key as NSString)
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}
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/// 清空内存缓存
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func clearCache() {
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cache.removeAllObjects()
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print("🧹 图片内存缓存已清空")
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}
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// MARK: - 文件缓存管理
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/// 保存图片到文件系统
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func saveImageToFile(_ image: UIImage, withName name: String) -> String? {
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let imagePath = (documentsPath as NSString).appendingPathComponent("\(name).jpg")
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if let imageData = image.jpegData(compressionQuality: 0.8) {
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do {
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try imageData.write(to: URL(fileURLWithPath: imagePath))
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print("💾 图片已保存到文件: \(imagePath)")
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return imagePath
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} catch {
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print("❌ 保存图片失败: \(error)")
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return nil
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}
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}
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return nil
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}
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/// 从文件系统加载图片
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func loadImageFromFile(path: String) -> UIImage? {
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return UIImage(contentsOfFile: path)
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}
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/// 删除文件系统中的图片
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func deleteImageFromFile(path: String) {
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do {
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try fileManager.removeItem(atPath: path)
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print("🗑️ 图片文件已删除: \(path)")
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} catch {
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print("❌ 删除图片文件失败: \(error)")
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}
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}
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/// 清理过期的文件缓存
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func cleanupExpiredFiles() {
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let imageCachePath = (documentsPath as NSString).appendingPathComponent("ImageCache")
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do {
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let files = try fileManager.contentsOfDirectory(atPath: imageCachePath)
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let currentDate = Date()
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for file in files {
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let filePath = (imageCachePath as NSString).appendingPathComponent(file)
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let attributes = try fileManager.attributesOfItem(atPath: filePath)
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if let creationDate = attributes[.creationDate] as? Date {
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// 删除7天前的文件
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if currentDate.timeIntervalSince(creationDate) > 7 * 24 * 60 * 60 {
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try fileManager.removeItem(atPath: filePath)
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print("🗑️ 删除过期文件: \(file)")
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}
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}
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}
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} catch {
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print("❌ 清理过期文件失败: \(error)")
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}
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}
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// MARK: - 智能缓存管理
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/// 智能获取图片（先查内存缓存，再查文件缓存）
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func getImageIntelligently(forKey key: String) -> UIImage? {
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// 1. 先查内存缓存
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if let cachedImage = getImage(forKey: key) {
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return cachedImage
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}
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// 2. 再查文件缓存
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let imagePath = (documentsPath as NSString).appendingPathComponent("\(key).jpg")
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if let fileImage = loadImageFromFile(path: imagePath) {
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// 加载到内存缓存
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setImage(fileImage, forKey: key)
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return fileImage
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}
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return nil
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}
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/// 智能保存图片（同时保存到内存和文件）
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func saveImageIntelligently(_ image: UIImage, forKey key: String) {
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// 1. 保存到内存缓存
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setImage(image, forKey: key)
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// 2. 保存到文件缓存
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_ = saveImageToFile(image, withName: key)
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}
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// MARK: - 内存警告处理
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@objc private func handleMemoryWarning() {
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print("🚨 收到内存警告，清理图片缓存")
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clearCache()
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}
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// MARK: - 缓存统计
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/// 获取缓存统计信息
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func getCacheStatistics() -> (memoryCount: Int, memorySize: String, fileCount: Int) {
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let memoryCount = cache.totalCostLimit > 0 ? cache.totalCostLimit : 0
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let memorySize = ByteCountFormatter.string(fromByteCount: Int64(memoryCount), countStyle: .memory)
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let imageCachePath = (documentsPath as NSString).appendingPathComponent("ImageCache")
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var fileCount = 0
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do {
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let files = try fileManager.contentsOfDirectory(atPath: imageCachePath)
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fileCount = files.count
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} catch {
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fileCount = 0
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}
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return (memoryCount, memorySize, fileCount)
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}
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/// 打印缓存统计信息
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func printCacheStatistics() {
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let stats = getCacheStatistics()
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print("📊 图片缓存统计:")
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print(" - 内存缓存数量: \(stats.memoryCount)")
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print(" - 内存缓存大小: \(stats.memorySize)")
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print(" - 文件缓存数量: \(stats.fileCount)")
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}
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}
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// MARK: - 图片压缩工具
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extension ImageCacheManager {
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/// 压缩图片到指定大小
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func compressImage(_ image: UIImage, maxSize: CGSize) -> UIImage {
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let originalSize = image.size
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// 如果图片已经小于最大尺寸，直接返回
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if originalSize.width <= maxSize.width && originalSize.height <= maxSize.height {
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return image
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}
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// 计算缩放比例
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let scaleX = maxSize.width / originalSize.width
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let scaleY = maxSize.height / originalSize.height
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let scale = min(scaleX, scaleY)
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let newSize = CGSize(width: originalSize.width * scale, height: originalSize.height * scale)
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// 重新渲染图片
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let renderer = UIGraphicsImageRenderer(size: newSize)
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return renderer.image { context in
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image.draw(in: CGRect(origin: .zero, size: newSize))
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}
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}
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/// 压缩图片到指定文件大小
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func compressImageToFileSize(_ image: UIImage, targetSizeInKB: Double) -> UIImage {
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let targetSizeInBytes = Int64(targetSizeInKB * 1024)
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// 尝试不同的压缩质量
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let compressionQualities: [CGFloat] = [0.8, 0.6, 0.4, 0.2, 0.1, 0.05]
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for quality in compressionQualities {
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if let imageData = image.jpegData(compressionQuality: quality) {
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let dataSize = Int64(imageData.count)
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if dataSize <= targetSizeInBytes {
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if let compressedImage = UIImage(data: imageData) {
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print("✅ 图片压缩成功: \(dataSize) bytes (质量: \(quality))")
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return compressedImage
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}
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}
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}
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}
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// 如果JPEG压缩仍然太大，尝试缩小尺寸
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print("⚠️ JPEG压缩后仍超过目标大小，尝试缩小尺寸")
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return compressImageByReducingSize(image, targetSizeInBytes: targetSizeInBytes)
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}
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/// 通过缩小尺寸来压缩图片
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private func compressImageByReducingSize(_ image: UIImage, targetSizeInBytes: Int64) -> UIImage {
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let originalSize = image.size
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let originalWidth = originalSize.width
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let originalHeight = originalSize.height
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// 计算当前图片的内存大小
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let currentMemorySize = Int64(originalWidth * originalHeight * 4) // 假设RGBA格式
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// 计算需要的缩放比例
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let scaleFactor = sqrt(Double(targetSizeInBytes) / Double(currentMemorySize))
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let newWidth = max(originalWidth * CGFloat(scaleFactor), 40) // 最小40像素
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let newHeight = max(originalHeight * CGFloat(scaleFactor), 40)
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let newSize = CGSize(width: newWidth, height: newHeight)
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// 重新渲染到新尺寸
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let renderer = UIGraphicsImageRenderer(size: newSize)
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let resizedImage = renderer.image { context in
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image.draw(in: CGRect(origin: .zero, size: newSize))
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}
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// 再次尝试JPEG压缩
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if let imageData = resizedImage.jpegData(compressionQuality: 0.3) {
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let finalSize = Int64(imageData.count)
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print("✅ 通过缩小尺寸压缩成功: \(finalSize) bytes (新尺寸: \(newWidth) x \(newHeight))")
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if let finalImage = UIImage(data: imageData) {
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return finalImage
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}
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}
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// 如果还是太大，返回最小尺寸的图片
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print("⚠️ 无法压缩到目标大小，返回最小尺寸图片")
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let minSize = CGSize(width: 40, height: 40)
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let rendererMin = UIGraphicsImageRenderer(size: minSize)
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return rendererMin.image { context in
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image.draw(in: CGRect(origin: .zero, size: minSize))
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}
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}
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}
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