improve:展台功能

Ink Canvas/Models/CapturedImage.cs

@@ -14,20 +14,28 @@ namespace Ink_Canvas.Models
 
         public CapturedImage(BitmapImage image)
         {
-            Image = image;
-            Thumbnail = CreateThumbnail(image);
+            if (image == null)
+                throw new ArgumentNullException(nameof(image), "图像不能为空");
+
+            // 确保 Image 被冻结，避免跨线程访问风险
+            Image = EnsureFrozen(image);
+            Thumbnail = CreateThumbnail(Image);
             Strokes = new StrokeCollection();
-            Timestamp = DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss");
+            Timestamp = DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss.fff");
             FilePath = null;
         }
 
         public CapturedImage(BitmapImage image, string filePath)
         {
-            Image = image;
-            Thumbnail = CreateThumbnail(image);
+            if (image == null)
+                throw new ArgumentNullException(nameof(image), "图像不能为空");
+
+            // 确保 Image 被冻结，避免跨线程访问风险
+            Image = EnsureFrozen(image);
+            Thumbnail = CreateThumbnail(Image);
             Strokes = new StrokeCollection();
             FilePath = filePath;
-            Timestamp = TryExtractTimestampFromFilePath(filePath) ?? DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss");
+            Timestamp = TryExtractTimestampFromFilePath(filePath) ?? DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss.fff");
         }
 
         private static string TryExtractTimestampFromFilePath(string filePath)
@@ -43,7 +51,7 @@ namespace Ink_Canvas.Models
                         System.Globalization.DateTimeStyles.None,
                         out var dt))
                 {
-                    return dt.ToString("yyyy-MM-dd HH:mm:ss");
+                    return dt.ToString("yyyy-MM-dd HH:mm:ss.fff");
                 }
                 if (name.Length >= 23)
                 {
@@ -55,7 +63,7 @@ namespace Ink_Canvas.Models
                             System.Globalization.DateTimeStyles.None,
                             out var dt2))
                     {
-                        return dt2.ToString("yyyy-MM-dd HH:mm:ss");
+                        return dt2.ToString("yyyy-MM-dd HH:mm:ss.fff");
                     }
                 }
                 return null;
@@ -66,11 +74,53 @@ namespace Ink_Canvas.Models
             }
         }
 
-        private BitmapImage CreateThumbnail(BitmapImage original)
+        private static BitmapImage EnsureFrozen(BitmapImage image)
         {
+            if (image == null)
+                throw new ArgumentNullException(nameof(image));
+
+            if (image.IsFrozen)
+                return image;
+
+            var encoder = new System.Windows.Media.Imaging.PngBitmapEncoder();
+            encoder.Frames.Add(System.Windows.Media.Imaging.BitmapFrame.Create(image));
+
+            var stream = new System.IO.MemoryStream();
+            encoder.Save(stream);
+            stream.Position = 0;
+
+            var frozenCopy = new BitmapImage();
+            frozenCopy.BeginInit();
+            frozenCopy.CacheOption = BitmapCacheOption.OnLoad;
+            frozenCopy.StreamSource = stream;
+            frozenCopy.EndInit();
+            frozenCopy.Freeze();
+
+            return frozenCopy;
+        }
+
+        private static BitmapImage CreateThumbnail(BitmapImage original)
+        {
+            if (original == null)
+                throw new ArgumentNullException(nameof(original));
+
+            if (original.PixelWidth <= 0 || original.PixelHeight <= 0)
+            {
+                throw new ArgumentException(
+                    $"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。",
+                    nameof(original));
+            }
+
             double targetWidth = 290.0;
             double targetHeight = 180.0;
             double scale = Math.Min(targetWidth / original.PixelWidth, targetHeight / original.PixelHeight);
+            
+            if (double.IsInfinity(scale) || double.IsNaN(scale) || scale <= 0)
+            {
+                throw new InvalidOperationException(
+                    $"无法计算有效的缩放比例：scale={scale}, 图像尺寸={original.PixelWidth}x{original.PixelHeight}");
+            }
+
             var thumbnail = new TransformedBitmap(original, new System.Windows.Media.ScaleTransform(scale, scale));
 
             var bmp = new JpegBitmapEncoder { QualityLevel = 85 };