close #397

src/Shared/HandyControl_Shared/Tools/Extension/ValueExtension.cs

@@ -1,9 +1,21 @@
 using System.Windows;
+using HandyControl.Expression.Drawing;
 
 namespace HandyControl.Tools.Extension
 {
     public static class ValueExtension
     {
         public static Thickness Add(this Thickness a, Thickness b) => new Thickness(a.Left + b.Left, a.Top + b.Top, a.Right + b.Right, a.Bottom + b.Bottom);
+
+        public static bool IsZero(this Thickness thickness) =>
+            MathHelper.IsZero(thickness.Left)
+            && MathHelper.IsZero(thickness.Top)
+            && MathHelper.IsZero(thickness.Right)
+            && MathHelper.IsZero(thickness.Bottom);
+
+        public static bool IsUniform(this Thickness thickness) =>
+            MathHelper.AreClose(thickness.Left, thickness.Top)
+            && MathHelper.AreClose(thickness.Left, thickness.Right)
+            && MathHelper.AreClose(thickness.Left, thickness.Bottom);
     }
 }

src/Shared/HandyControl_Shared/Tools/GifImageAnimator.cs

@@ -92,10 +92,7 @@ namespace HandyControl.Tools
                 {
                     // Construct the image array
                     //                               
-                    if (ImageInfoList == null)
-                    {
-                        ImageInfoList = new List<GifImageInfo>();
-                    }
+                    ImageInfoList ??= new List<GifImageInfo>();
 
                     // Add the new image
                     //
@@ -108,7 +105,7 @@ namespace HandyControl.Tools
                     {
                         AnimationThread = new Thread(AnimateImages50Ms)
                         {
-                            Name = typeof(ImageAnimator).Name,
+                            Name = nameof(ImageAnimator),
                             IsBackground = true
                         };
                         AnimationThread.Start();
@@ -168,13 +165,18 @@ namespace HandyControl.Tools
 
                     if (Equals(image, imageInfo.Image))
                     {
-                        if ((onFrameChangedHandler == imageInfo.FrameChangedHandler) || (onFrameChangedHandler != null && onFrameChangedHandler.Equals(imageInfo.FrameChangedHandler)))
+                        if (onFrameChangedHandler == imageInfo.FrameChangedHandler || onFrameChangedHandler != null && onFrameChangedHandler.Equals(imageInfo.FrameChangedHandler))
                         {
                             ImageInfoList.Remove(imageInfo);
                         }
                         break;
                     }
                 }
+
+                if (!ImageInfoList.Any())
+                {
+                    AnimationThread = null;
+                }
             }
             finally
             {
@@ -224,7 +226,7 @@ namespace HandyControl.Tools
         [SuppressMessage("Microsoft.Performance", "CA1804:RemoveUnusedLocals")]
         private static void AnimateImages50Ms()
         {
-            while (true)
+            while (ImageInfoList.Any())
             {
                 // Acquire reader-lock to access imageInfoList, elemens in the list can be modified w/o needing a writer-lock.
                 // Observe that we don't need to check if the thread is waiting or a writer lock here since the thread this 

src/Shared/HandyControl_Shared/Tools/Helper/DpiHelper.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Windows;
 using System.Windows.Media;
+using HandyControl.Expression.Drawing;
 using HandyControl.Tools.Interop;
 
 namespace HandyControl.Tools
@@ -79,5 +80,25 @@ namespace HandyControl.Tools
             result.Transform(TransformFromDevice.Matrix);
             return result;
         }
+
+        public static double RoundLayoutValue(double value, double dpiScale)
+        {
+            double newValue;
+
+            if (!MathHelper.AreClose(dpiScale, 1.0))
+            {
+                newValue = Math.Round(value * dpiScale) / dpiScale;
+                if (double.IsNaN(newValue) || double.IsInfinity(newValue) || MathHelper.AreClose(newValue, double.MaxValue))
+                {
+                    newValue = value;
+                }
+            }
+            else
+            {
+                newValue = Math.Round(value);
+            }
+
+            return newValue;
+        }
     }
 }