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https://github.com/DrizzleTime/Foxel.git
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345 lines
13 KiB
C#
345 lines
13 KiB
C#
using SixLabors.ImageSharp;
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using SixLabors.ImageSharp.Processing;
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using SixLabors.ImageSharp.Metadata.Profiles.Exif;
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using System.Globalization;
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using Foxel.Models;
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using SixLabors.ImageSharp.PixelFormats;
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namespace Foxel.Utils;
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/// <summary>
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/// 图片处理工具类
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/// </summary>
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public static class ImageHelper
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{
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/// <summary>
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/// 获取完整URL路径
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/// </summary>
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/// <param name="serverUrl">服务器URL</param>
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/// <param name="relativePath">相对路径</param>
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/// <returns>完整URL路径</returns>
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public static string GetFullPath(string serverUrl, string relativePath)
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{
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if (string.IsNullOrEmpty(relativePath))
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return string.Empty;
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if (relativePath.StartsWith("https://"))
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return relativePath;
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return $"{serverUrl.TrimEnd('/')}{relativePath}";
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}
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/// <summary>
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/// 创建缩略图
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/// </summary>
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/// <param name="originalPath">原始图片路径</param>
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/// <param name="thumbnailPath">缩略图保存路径</param>
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/// <param name="width">缩略图宽度</param>
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/// <param name="quality">压缩质量(1-100)</param>
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/// <returns>生成的缩略图的文件大小（字节）</returns>
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public static async Task<long> CreateThumbnailAsync(string originalPath, string thumbnailPath, int width,
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int quality = 75)
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{
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// 获取原始文件大小
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var originalFileInfo = new FileInfo(originalPath);
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long originalSize = originalFileInfo.Length;
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using var image = await Image.LoadAsync(originalPath);
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// 去除EXIF元数据以减小文件大小
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image.Metadata.ExifProfile = null;
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image.Mutate(x => x.Resize(new ResizeOptions
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{
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Size = new Size(width, 0),
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Mode = ResizeMode.Max
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}));
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string extension = Path.GetExtension(thumbnailPath).ToLower();
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// 根据原图大小动态调整质量
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int adjustedQuality = AdjustQualityByFileSize(originalSize, extension, quality);
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if (extension == ".jpg" || extension == ".jpeg")
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{
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await image.SaveAsJpegAsync(thumbnailPath, new SixLabors.ImageSharp.Formats.Jpeg.JpegEncoder
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{
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Quality = adjustedQuality
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});
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}
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else if (extension == ".png")
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{
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await image.SaveAsPngAsync(thumbnailPath, new SixLabors.ImageSharp.Formats.Png.PngEncoder
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{
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CompressionLevel = SixLabors.ImageSharp.Formats.Png.PngCompressionLevel.BestCompression,
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ColorType = SixLabors.ImageSharp.Formats.Png.PngColorType.RgbWithAlpha, // 确保使用最优的颜色类型
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FilterMethod = SixLabors.ImageSharp.Formats.Png.PngFilterMethod.Adaptive // 使用自适应过滤
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});
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}
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else
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{
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await image.SaveAsync(thumbnailPath);
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}
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var thumbnailFileInfo = new FileInfo(thumbnailPath);
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if (thumbnailFileInfo.Length < originalSize) return thumbnailFileInfo.Length;
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// 再次尝试优化，但不改变扩展名
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if (extension == ".png")
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{
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await image.SaveAsPngAsync(thumbnailPath, new SixLabors.ImageSharp.Formats.Png.PngEncoder
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{
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CompressionLevel = SixLabors.ImageSharp.Formats.Png.PngCompressionLevel.BestCompression,
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FilterMethod = SixLabors.ImageSharp.Formats.Png.PngFilterMethod.Adaptive
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});
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thumbnailFileInfo = new FileInfo(thumbnailPath);
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}
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else if (extension == ".jpg" || extension == ".jpeg")
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{
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// 如果是 JPEG，尝试降低质量进一步压缩
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await image.SaveAsJpegAsync(thumbnailPath, new SixLabors.ImageSharp.Formats.Jpeg.JpegEncoder
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{
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Quality = Math.Max(adjustedQuality - 10, 60) // 再降低质量但不低于60
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});
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thumbnailFileInfo = new FileInfo(thumbnailPath);
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}
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return thumbnailFileInfo.Length;
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}
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/// <summary>
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/// 检查图像是否包含透明像素
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/// </summary>
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/// <param name="image">要检查的图像</param>
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/// <returns>如果图像包含透明像素则返回true</returns>
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private static bool HasTransparency(Image image)
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{
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// 检查图像格式是否支持透明度
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if (image.PixelType.AlphaRepresentation == PixelAlphaRepresentation.None)
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{
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return false; // 图像格式不支持透明度
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}
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// 对于小图片，逐像素检查是否有透明度
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if (image.Width * image.Height <= 1000 * 1000) // 对于不超过1000x1000的图片
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{
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using var imageWithAlpha = image.CloneAs<Rgba32>();
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for (int y = 0; y < imageWithAlpha.Height; y++)
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{
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for (int x = 0; x < imageWithAlpha.Width; x++)
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{
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if (imageWithAlpha[x, y].A < 255)
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{
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return true;
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}
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}
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}
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return false;
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}
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else
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{
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using var imageWithAlpha = image.CloneAs<Rgba32>();
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int sampleSize = Math.Max(image.Width, image.Height) / 100;
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sampleSize = Math.Max(1, sampleSize);
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for (int y = 0; y < imageWithAlpha.Height; y += sampleSize)
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{
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for (int x = 0; x < imageWithAlpha.Width; x += sampleSize)
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{
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if (imageWithAlpha[x, y].A < 255)
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{
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return true;
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}
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}
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}
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return false;
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}
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}
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/// <summary>
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/// 根据原始文件大小调整质量参数
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/// </summary>
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private static int AdjustQualityByFileSize(long originalSize, string extension, int baseQuality)
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{
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if (extension == ".jpg" || extension == ".jpeg")
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{
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if (originalSize > 10 * 1024 * 1024) // 10MB
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return Math.Min(baseQuality, 65);
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else if (originalSize > 5 * 1024 * 1024) // 5MB
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return Math.Min(baseQuality, 70);
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else if (originalSize > 1 * 1024 * 1024) // 1MB
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return Math.Min(baseQuality, 75);
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}
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return baseQuality;
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}
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/// <summary>
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/// 将图片转换为Base64编码
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/// </summary>
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/// <param name="imagePath">图片路径</param>
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/// <returns>Base64编码字符串</returns>
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public static async Task<string> ConvertImageToBase64(string imagePath)
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{
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byte[] imageBytes = await File.ReadAllBytesAsync(imagePath);
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return Convert.ToBase64String(imageBytes);
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}
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/// <summary>
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/// 提取图片的EXIF信息
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/// </summary>
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/// <param name="imagePath">图片路径</param>
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/// <returns>EXIF信息对象</returns>
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public static async Task<ExifInfo> ExtractExifInfoAsync(string imagePath)
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{
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var exifInfo = new ExifInfo();
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try
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{
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// 确保文件存在
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if (!File.Exists(imagePath))
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{
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exifInfo.ErrorMessage = "找不到图片文件";
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return exifInfo;
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}
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// 使用ImageSharp读取EXIF信息
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using var image = await Image.LoadAsync(imagePath);
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var exifProfile = image.Metadata.ExifProfile;
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// 添加基本图像信息
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exifInfo.Width = image.Width;
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exifInfo.Height = image.Height;
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if (exifProfile != null)
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{
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// 提取相机信息
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if (exifProfile.TryGetValue(ExifTag.Make, out var make))
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exifInfo.CameraMaker = make.Value;
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if (exifProfile.TryGetValue(ExifTag.Model, out var model))
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exifInfo.CameraModel = model.Value;
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if (exifProfile.TryGetValue(ExifTag.Software, out var software))
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exifInfo.Software = software.Value;
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// 提取拍摄参数
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if (exifProfile.TryGetValue(ExifTag.ExposureTime, out var exposureTime))
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exifInfo.ExposureTime = exposureTime.Value.ToString();
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if (exifProfile.TryGetValue(ExifTag.FNumber, out var fNumber))
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exifInfo.Aperture = $"f/{fNumber.Value}";
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if (exifProfile.TryGetValue(ExifTag.ISOSpeedRatings, out var iso))
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{
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if (iso.Value is { Length: > 0 } isoArray)
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{
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exifInfo.IsoSpeed = isoArray[0].ToString();
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}
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else
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{
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exifInfo.IsoSpeed = iso.Value?.ToString();
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}
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}
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if (exifProfile.TryGetValue(ExifTag.FocalLength, out var focalLength))
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exifInfo.FocalLength = $"{focalLength.Value}mm";
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if (exifProfile.TryGetValue(ExifTag.Flash, out var flash))
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exifInfo.Flash = flash.Value.ToString();
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if (exifProfile.TryGetValue(ExifTag.MeteringMode, out var meteringMode))
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exifInfo.MeteringMode = meteringMode.Value.ToString();
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if (exifProfile.TryGetValue(ExifTag.WhiteBalance, out var whiteBalance))
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exifInfo.WhiteBalance = whiteBalance.Value.ToString();
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// 提取时间信息并确保存储为字符串
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if (exifProfile.TryGetValue(ExifTag.DateTimeOriginal, out var dateTime))
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{
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exifInfo.DateTimeOriginal = dateTime.Value;
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// 解析日期时间
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if (DateTime.TryParseExact(dateTime.Value, "yyyy:MM:dd HH:mm:ss", CultureInfo.InvariantCulture,
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DateTimeStyles.None, out _))
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{
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// 只在ExifInfo中保留原始字符串格式
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}
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}
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// 提取GPS信息
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if (exifProfile.TryGetValue(ExifTag.GPSLatitude, out var latitude) &&
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exifProfile.TryGetValue(ExifTag.GPSLatitudeRef, out var latitudeRef))
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{
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string? latRef = latitudeRef.Value;
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exifInfo.GpsLatitude = ConvertGpsCoordinateToString(latitude.Value, latRef == "S");
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}
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if (exifProfile.TryGetValue(ExifTag.GPSLongitude, out var longitude) &&
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exifProfile.TryGetValue(ExifTag.GPSLongitudeRef, out var longitudeRef))
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{
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string? longRef = longitudeRef.Value;
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exifInfo.GpsLongitude = ConvertGpsCoordinateToString(longitude.Value, longRef == "W");
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}
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}
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}
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catch (Exception ex)
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{
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exifInfo.ErrorMessage = $"提取EXIF信息时出错: {ex.Message}";
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}
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return exifInfo;
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}
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/// <summary>
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/// 将GPS坐标转换为字符串表示
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/// </summary>
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/// <param name="rationals">GPS坐标的有理数数组（度、分、秒）</param>
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/// <param name="isNegative">是否为负值（南纬/西经）</param>
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/// <returns>十进制格式的GPS坐标</returns>
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private static string? ConvertGpsCoordinateToString(Rational[]? rationals, bool isNegative)
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{
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if (rationals == null || rationals.Length < 3)
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return null;
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try
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{
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// 度分秒转换为十进制度
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double degrees = rationals[0].Numerator / (double)rationals[0].Denominator;
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double minutes = rationals[1].Numerator / (double)rationals[1].Denominator;
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double seconds = rationals[2].Numerator / (double)rationals[2].Denominator;
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double coordinate = degrees + (minutes / 60) + (seconds / 3600);
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// 如果是南纬或西经，则为负值
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if (isNegative)
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coordinate = -coordinate;
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return coordinate.ToString(CultureInfo.InvariantCulture);
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}
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catch
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{
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return null;
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}
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}
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/// <summary>
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/// 从EXIF信息中解析拍摄时间
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/// </summary>
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/// <param name="dateTimeOriginal">EXIF中的拍摄时间字符串</param>
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/// <returns>UTC格式的日期时间，如果解析失败则返回null</returns>
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public static DateTime? ParseExifDateTime(string? dateTimeOriginal)
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{
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if (string.IsNullOrEmpty(dateTimeOriginal))
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return null;
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if (DateTime.TryParseExact(dateTimeOriginal, "yyyy:MM:dd HH:mm:ss", CultureInfo.InvariantCulture,
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DateTimeStyles.None, out var parsedDate))
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{
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return DateTime.SpecifyKind(parsedDate, DateTimeKind.Local).ToUniversalTime();
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}
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return null;
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}
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} |