176 lines
7.9 KiB
C#
176 lines
7.9 KiB
C#
using System;
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using System.Windows.Ink;
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using System.Windows.Media.Imaging;
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namespace Ink_Canvas.Models
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{
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public class CapturedImage
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{
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public BitmapImage Image { get; }
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public BitmapImage Thumbnail { get; }
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public StrokeCollection Strokes { get; }
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public string Timestamp { get; }
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public string FilePath { get; }
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/// <summary>
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/// 使用指定的位图创建一个 CapturedImage 实例，并为其生成缩略图、空白笔划集合和时间戳。
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/// </summary>
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/// <param name="image">用于初始化的位图；不能为空。传入的图像将在内部确保为冻结状态以便安全跨线程使用。</param>
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/// <exception cref="System.ArgumentNullException">当 <paramref name="image"/> 为 null 时抛出。</exception>
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public CapturedImage(BitmapImage image)
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{
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if (image == null)
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throw new ArgumentNullException(nameof(image), "图像不能为空");
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// 确保 Image 被冻结，避免跨线程访问风险
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Image = EnsureFrozen(image);
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Thumbnail = CreateThumbnail(Image);
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Strokes = new StrokeCollection();
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Timestamp = DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss.fff");
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FilePath = null;
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}
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/// <summary>
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/// 初始化 CapturedImage 实例：将指定图像冻结用于线程安全、生成缩略图并初始化空的笔迹集合，同时设置文件路径和时间戳（尝试从文件名提取时间戳，失败则使用当前时间）。
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/// </summary>
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/// <param name="image">源图像，不能为空。</param>
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/// <param name="filePath">关联文件的路径，可能为 null。</param>
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/// <exception cref="ArgumentNullException">当 <paramref name="image"/> 为 null 时抛出。</exception>
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public CapturedImage(BitmapImage image, string filePath)
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{
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if (image == null)
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throw new ArgumentNullException(nameof(image), "图像不能为空");
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// 确保 Image 被冻结，避免跨线程访问风险
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Image = EnsureFrozen(image);
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Thumbnail = CreateThumbnail(Image);
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Strokes = new StrokeCollection();
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FilePath = filePath;
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Timestamp = TryExtractTimestampFromFilePath(filePath) ?? DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss.fff");
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}
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/// <summary>
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/// 尝试从给定文件路径的文件名中解析并返回规范化的时间戳。
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/// </summary>
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/// <param name="filePath">要从其文件名中解析时间戳的文件路径；可以为 null 或空字符串。</param>
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/// <returns>解析得到的时间戳，格式为 "yyyy-MM-dd HH:mm:ss.fff"；无法解析时返回 null。</returns>
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private static string TryExtractTimestampFromFilePath(string filePath)
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{
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try
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{
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if (string.IsNullOrEmpty(filePath)) return null;
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var name = System.IO.Path.GetFileNameWithoutExtension(filePath);
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if (DateTime.TryParseExact(
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name,
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"yyyy-MM-dd HH-mm-ss-fff",
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System.Globalization.CultureInfo.InvariantCulture,
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System.Globalization.DateTimeStyles.None,
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out var dt))
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{
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return dt.ToString("yyyy-MM-dd HH:mm:ss.fff");
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}
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if (name.Length >= 23)
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{
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var tail = name.Substring(name.Length - 23);
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if (DateTime.TryParseExact(
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tail,
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"yyyy-MM-dd HH-mm-ss-fff",
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System.Globalization.CultureInfo.InvariantCulture,
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System.Globalization.DateTimeStyles.None,
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out var dt2))
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{
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return dt2.ToString("yyyy-MM-dd HH:mm:ss.fff");
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}
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}
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return null;
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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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/// 确保并返回一个已冻结的 BitmapImage 副本，以便在跨线程场景中安全使用。
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/// </summary>
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/// <param name="image">要确保为冻结状态的源 BitmapImage。</param>
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/// <returns>与输入图像内容一致且已调用 Freeze 的 BitmapImage 实例。</returns>
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/// <exception cref="ArgumentNullException">在 <paramref name="image"/> 为 null 时抛出。</exception>
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private static BitmapImage EnsureFrozen(BitmapImage image)
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{
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if (image == null)
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throw new ArgumentNullException(nameof(image));
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if (image.IsFrozen)
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return image;
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var encoder = new System.Windows.Media.Imaging.PngBitmapEncoder();
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encoder.Frames.Add(System.Windows.Media.Imaging.BitmapFrame.Create(image));
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var stream = new System.IO.MemoryStream();
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encoder.Save(stream);
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stream.Position = 0;
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var frozenCopy = new BitmapImage();
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frozenCopy.BeginInit();
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frozenCopy.CacheOption = BitmapCacheOption.OnLoad;
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frozenCopy.StreamSource = stream;
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frozenCopy.EndInit();
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frozenCopy.Freeze();
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return frozenCopy;
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}
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/// <summary>
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/// 生成并返回一个在 290×180 约束内按比例缩放并已冻结的缩略图。
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/// </summary>
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/// <param name="original">用于生成缩略图的源 <see cref="BitmapImage"/>；不得为 <c>null</c>，且其像素宽度和高度必须大于 0。</param>
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/// <returns>已冻结的 <see cref="BitmapImage"/> 缩略图，尺寸不超过 290×180 且保持原图纵横比。</returns>
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/// <exception cref="ArgumentNullException">当 <paramref name="original"/> 为 <c>null</c> 时抛出。</exception>
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/// <exception cref="ArgumentException">当 <paramref name="original"/> 的像素宽度或高度小于等于 0 时抛出。</exception>
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/// <exception cref="InvalidOperationException">当无法计算出有效的缩放比例（例如结果为 NaN、Infinity 或非正数）时抛出。</exception>
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private static BitmapImage CreateThumbnail(BitmapImage original)
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{
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if (original == null)
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throw new ArgumentNullException(nameof(original));
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if (original.PixelWidth <= 0 || original.PixelHeight <= 0)
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{
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throw new ArgumentException(
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$"图像尺寸无效：宽度={original.PixelWidth}, 高度={original.PixelHeight}。图像必须具有有效的像素尺寸。",
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nameof(original));
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}
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double targetWidth = 290.0;
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double targetHeight = 180.0;
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double scale = Math.Min(targetWidth / original.PixelWidth, targetHeight / original.PixelHeight);
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if (double.IsInfinity(scale) || double.IsNaN(scale) || scale <= 0)
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{
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throw new InvalidOperationException(
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$"无法计算有效的缩放比例：scale={scale}, 图像尺寸={original.PixelWidth}x{original.PixelHeight}");
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}
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var thumbnail = new TransformedBitmap(original, new System.Windows.Media.ScaleTransform(scale, scale));
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var bmp = new JpegBitmapEncoder { QualityLevel = 85 };
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bmp.Frames.Add(BitmapFrame.Create(thumbnail));
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using (var stream = new System.IO.MemoryStream())
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{
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bmp.Save(stream);
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stream.Seek(0, System.IO.SeekOrigin.Begin);
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var result = new BitmapImage();
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result.BeginInit();
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result.CacheOption = BitmapCacheOption.OnLoad;
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result.StreamSource = stream;
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result.EndInit();
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result.Freeze();
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return result;
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}
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}
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}
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}
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