improve:显示画笔光标

Ink Canvas/MainWindow.xaml.cs

@@ -72,7 +72,8 @@ namespace Ink_Canvas
         // 全屏处理状态标志
         public bool isFullScreenApplied = false;
 
-
+        private static Cursor _cachedPenCursor = null;
+        private static readonly object _cursorLock = new object();
 
         #region Window Initialization
 
@@ -1363,9 +1364,31 @@ namespace Ink_Canvas
                 }
                 else if (canvas.EditingMode == InkCanvasEditingMode.Ink)
                 {
-                    var sri = Application.GetResourceStream(new Uri("Resources/Cursors/Pen.cur", UriKind.Relative));
-                    if (sri != null)
-                        canvas.Cursor = new Cursor(sri.Stream);
+                    if (_cachedPenCursor == null)
+                    {
+                        lock (_cursorLock)
+                        {
+                            if (_cachedPenCursor == null)
+                            {
+                                try
+                                {
+                                    var sri = Application.GetResourceStream(new Uri("Resources/Cursors/Pen.cur", UriKind.Relative));
+                                    if (sri != null)
+                                    {
+                                        _cachedPenCursor = new Cursor(sri.Stream);
+                                    }
+                                }
+                                catch (Exception ex)
+                                {
+                                    LogHelper.WriteLogToFile($"加载 Pen 光标资源失败: {ex.Message}", LogHelper.LogType.Error);
+                                }
+                            }
+                        }
+                    }
+                    if (_cachedPenCursor != null)
+                    {
+                        canvas.Cursor = _cachedPenCursor;
+                    }
                 }
 
                 // 确保光标可见，无论是鼠标、触控还是手写笔