update AnimationPath

The PathLength can now be calculated automatically

HandyControl/Tools/Extension/GeometryExtension.cs

@@ -0,0 +1,50 @@
+using System;
+using System.Windows;
+using System.Windows.Media;
+using HandyControl.Expression.Drawing;
+
+namespace HandyControl.Tools.Extension
+{
+    public static class GeometryExtension
+    {
+        /// <summary>
+        ///     获取路径总长度
+        /// </summary>
+        /// <param name="geometry"></param>
+        /// <returns></returns>
+        public static double GetTotalLength(this Geometry geometry)
+        {
+            if (geometry == null) return 0;
+
+            var pathGeometry = PathGeometry.CreateFromGeometry(geometry);
+            pathGeometry.GetPointAtFractionLength(1e-4, out var point, out _);
+            var length = (pathGeometry.Figures[0].StartPoint - point).Length * 1e+4;
+
+            return length;
+        }
+
+        /// <summary>
+        ///     获取路径总长度
+        /// </summary>
+        /// <param name="geometry"></param>
+        /// <param name="size"></param>
+        /// <param name="strokeThickness"></param>
+        /// <returns></returns>
+        public static double GetTotalLength(this Geometry geometry, Size size, double strokeThickness = 1)
+        {
+            if (geometry == null) return 0;
+
+            if (MathHelper.IsVerySmall(size.Width) || MathHelper.IsVerySmall(size.Height)) return 0;
+
+            var length = GetTotalLength(geometry);
+            var sw = geometry.Bounds.Width / size.Width;
+            var sh = geometry.Bounds.Height / size.Height;
+            var min = Math.Min(sw, sh);
+
+            if (MathHelper.IsVerySmall(min) || MathHelper.IsVerySmall(strokeThickness)) return 0;
+
+            length /= min;
+            return length / strokeThickness;
+        }
+    }
+}