diff --git a/SpineRuntimes/SpineRuntime21/Bone.cs b/SpineRuntimes/SpineRuntime21/Bone.cs
index 286fd6a..52cdbeb 100644
--- a/SpineRuntimes/SpineRuntime21/Bone.cs
+++ b/SpineRuntimes/SpineRuntime21/Bone.cs
@@ -33,7 +33,7 @@ using System.Collections.Generic;
 
 namespace SpineRuntime21 {
 	public class Bone{
-		static public bool yDown;
+		static readonly public bool yDown = false;
 
 		internal BoneData data;
 		internal Skeleton skeleton;
@@ -84,7 +84,8 @@ namespace SpineRuntime21 {
 
 		/// <summary>Computes the world SRT using the parent bone and the local SRT.</summary>
 		public void UpdateWorldTransform () {
-			Bone parent = this.parent;
+            float sx = skeleton.scaleX, sy = skeleton.scaleY;
+            Bone parent = this.parent;
 			float x = this.x, y = this.y;
 			if (parent != null) {
 				worldX = x * parent.m00 + y * parent.m01 + parent.worldX;
@@ -100,34 +101,22 @@ namespace SpineRuntime21 {
 				worldFlipX = parent.worldFlipX != flipX;
 				worldFlipY = parent.worldFlipY != flipY;
 			} else {
-				Skeleton skeleton = this.skeleton;
-				bool skeletonFlipX = skeleton.flipX, skeletonFlipY = skeleton.flipY;
-				worldX = skeletonFlipX ? -x : x;
-				worldY = skeletonFlipY != yDown ? -y : y;
+                worldX = x * sx;
+				worldY = y * sy;
 				worldScaleX = scaleX;
 				worldScaleY = scaleY;
 				worldRotation = rotationIK;
-				worldFlipX = skeletonFlipX != flipX;
-				worldFlipY = skeletonFlipY != flipY;
+				worldFlipX = (sx < 0) != flipX;
+				worldFlipY = (sy < 0) != flipY;
 			}
 			float radians = worldRotation * (float)Math.PI / 180;
 			float cos = (float)Math.Cos(radians);
 			float sin = (float)Math.Sin(radians);
-			if (worldFlipX) {
-				m00 = -cos * worldScaleX;
-				m01 = sin * worldScaleY;
-			} else {
-				m00 = cos * worldScaleX;
-				m01 = -sin * worldScaleY;
-			}
-			if (worldFlipY != yDown) {
-				m10 = -sin * worldScaleX;
-				m11 = -cos * worldScaleY;
-			} else {
-				m10 = sin * worldScaleX;
-				m11 = cos * worldScaleY;
-			}
-		}
+            m00 = cos * worldScaleX * sx;
+            m01 = -sin * worldScaleY * sx;
+            m10 = sin * worldScaleX * sy;
+			m11 = cos * worldScaleY * sy;
+        }
 
 		public void SetToSetupPose () {
 			BoneData data = this.data;
diff --git a/SpineRuntimes/SpineRuntime21/Skeleton.cs b/SpineRuntimes/SpineRuntime21/Skeleton.cs
index 53075b7..11d8763 100644
--- a/SpineRuntimes/SpineRuntime21/Skeleton.cs
+++ b/SpineRuntimes/SpineRuntime21/Skeleton.cs
@@ -42,8 +42,8 @@ namespace SpineRuntime21 {
 		internal Skin skin;
 		internal float r = 1, g = 1, b = 1, a = 1;
 		internal float time;
-		internal bool flipX, flipY;
-		internal float x, y;
+        internal float scaleX = 1, scaleY = 1;
+        internal float x, y;
 
 		public SkeletonData Data { get { return data; } }
 		public List<Bone> Bones { get { return bones; } }
@@ -58,10 +58,16 @@ namespace SpineRuntime21 {
 		public float Time { get { return time; } set { time = value; } }
 		public float X { get { return x; } set { x = value; } }
 		public float Y { get { return y; } set { y = value; } }
-		public bool FlipX { get { return flipX; } set { flipX = value; } }
-		public bool FlipY { get { return flipY; } set { flipY = value; } }
+        public float ScaleX { get { return scaleX; } set { scaleX = value; } }
+        public float ScaleY { get { return scaleY; } set { scaleY = value; } }
 
-		public Bone RootBone {
+        [Obsolete("Use ScaleX instead. FlipX is when ScaleX is negative.")]
+        public bool FlipX { get { return scaleX < 0; } set { scaleX = value ? -1f : 1f; } }
+
+        [Obsolete("Use ScaleY instead. FlipY is when ScaleY is negative.")]
+        public bool FlipY { get { return scaleY < 0; } set { scaleY = value ? -1f : 1f; } }
+
+        public Bone RootBone {
 			get {
 				return bones.Count == 0 ? null : bones[0];
 			}
diff --git a/SpineViewer/Spine/Implementations/SpineObject/SpineObject21.cs b/SpineViewer/Spine/Implementations/SpineObject/SpineObject21.cs
index a670bbf..4cd6dcb 100644
--- a/SpineViewer/Spine/Implementations/SpineObject/SpineObject21.cs
+++ b/SpineViewer/Spine/Implementations/SpineObject/SpineObject21.cs
@@ -123,45 +123,11 @@ namespace SpineViewer.Spine.Implementations.SpineObject
 
         protected override float scale
         {
-            get
-            {
-                if (skeletonBinary is not null)
-                    return skeletonBinary.Scale;
-                else if (skeletonJson is not null)
-                    return skeletonJson.Scale;
-                else
-                    return 1f;
-            }
+            get => Math.Abs(skeleton.ScaleX);
             set
             {
-                // 保存状态
-                var pos = position;
-                var fX = flipX;
-                var fY = flipY;
-                var animations = animationState.Tracks.Where(te => te is not null).Select(te => te.Animation.Name).ToArray();
-
-                if (skeletonBinary is not null)
-                {
-                    skeletonBinary.Scale = value;
-                    skeletonData = skeletonBinary.ReadSkeletonData(SkelPath);
-                }
-                else if (skeletonJson is not null)
-                {
-                    skeletonJson.Scale = value;
-                    skeletonData = skeletonJson.ReadSkeletonData(SkelPath);
-                }
-
-                // reload skel-dependent data
-                skeleton = new Skeleton(skeletonData) { Skin = new(Guid.NewGuid().ToString()) };
-                animationStateData = new AnimationStateData(skeletonData) { DefaultMix = animationStateData.DefaultMix };
-                animationState = new AnimationState(animationStateData);
-
-                // 恢复状态
-                position = pos;
-                flipX = fX;
-                flipY = fY;
-                reloadSkins();
-                for (int i = 0; i < animations.Length; i++) setAnimation(i, animations[i]);
+                skeleton.ScaleX = Math.Sign(skeleton.ScaleX) * value;
+                skeleton.ScaleY = Math.Sign(skeleton.ScaleY) * value;
             }
         }
 
@@ -177,14 +143,22 @@ namespace SpineViewer.Spine.Implementations.SpineObject
 
         protected override bool flipX
         {
-            get => skeleton.FlipX;
-            set => skeleton.FlipX = value;
+            get => skeleton.ScaleX < 0;
+            set
+            {
+                if (skeleton.ScaleX > 0 && value || skeleton.ScaleX < 0 && !value)
+                    skeleton.ScaleX *= -1;
+            }
         }
 
         protected override bool flipY
         {
-            get => skeleton.FlipY;
-            set => skeleton.FlipY = value;
+            get => skeleton.ScaleY < 0;
+            set
+            {
+                if (skeleton.ScaleY > 0 && value || skeleton.ScaleY < 0 && !value)
+                    skeleton.ScaleY *= -1;
+            }
         }
 
         protected override string getSlotAttachment(string slot) => skeleton.FindSlot(slot)?.Attachment?.Name ?? EMPTY_ATTACHMENT;
@@ -243,8 +217,8 @@ namespace SpineViewer.Spine.Implementations.SpineObject
             var maxDuration = 0f;
             var tmpSkeleton = new Skeleton(skeletonData) { Skin = new(Guid.NewGuid().ToString()) };
             var tmpAnimationState = new AnimationState(animationStateData);
-            tmpSkeleton.FlipX = skeleton.FlipX;
-            tmpSkeleton.FlipY = skeleton.FlipY;
+            tmpSkeleton.ScaleX = skeleton.ScaleX;
+            tmpSkeleton.ScaleY = skeleton.ScaleY;
             tmpSkeleton.X = skeleton.X;
             tmpSkeleton.Y = skeleton.Y;
             foreach (var (name, _) in skinLoadStatus.Where(e => e.Value))