Add resize handle class and reuse some resize handle uss styling in inspector window

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Drawing/Inspector/GraphInspectorView.cs

 {
     public class GraphInspectorView : VisualElement, IDisposable
     {
-        enum ResizeDirection
-        {
-            Any,
-            Vertical,
-            Horizontal
-        }
-
         int m_SelectionHash;
 
         VisualElement m_PropertyItems;
             foreach (var property in m_Graph.properties)
                 m_PropertyItems.Add(new ShaderPropertyView(m_Graph, property));
 
-            var resizeHandleTop = new Label { name = "resize-top", text = "" };
-            resizeHandleTop.AddManipulator(new Draggable(mouseDelta => OnResize(mouseDelta, ResizeDirection.Vertical, true)));
-            Add(resizeHandleTop);
-
-            var resizeHandleRight = new Label { name = "resize-right", text = "" };
-            resizeHandleRight.AddManipulator(new Draggable(mouseDelta => OnResize(mouseDelta, ResizeDirection.Horizontal, false)));
-            Add(resizeHandleRight);
-
-            var resizeHandleLeft = new Label { name = "resize-left", text = "" };
-            resizeHandleLeft.AddManipulator(new Draggable(mouseDelta => OnResize(mouseDelta, ResizeDirection.Horizontal, true)));
-            Add(resizeHandleLeft);
-
-            var resizeHandleBottom = new Label { name = "resize-bottom", text = "" };
-            resizeHandleBottom.AddManipulator(new Draggable(mouseDelta => OnResize(mouseDelta, ResizeDirection.Vertical, false)));
-            Add(resizeHandleBottom);
+            Add(new ResizeSideHandle(this, ResizeHandleAnchor.Top, new string[] {"resize", "vertical", "top"}));
+            Add(new ResizeSideHandle(this, ResizeHandleAnchor.Right, new string[] {"resize", "horizontal", "right"}));
+            Add(new ResizeSideHandle(this, ResizeHandleAnchor.Bottom, new string[] {"resize", "vertical", "bottom"}));
+            Add(new ResizeSideHandle(this, ResizeHandleAnchor.Left, new string[] {"resize", "horizontal", "left"}));
 
             // Nodes missing custom editors:
             // - PropertyNode

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Resources/Styles/MaterialGraph.uss

     padding-bottom: 4;
 }
 
-GraphInspectorView > #resize-right {
-    cursor: resize-horizontal;
+GraphInspectorView > .resize {
-    width: 10;
+}
+
+GraphInspectorView > .resize.vertical {
+    cursor: resize-vertical;
+    height: 10;
+    position-left: 0;
-    position-top: 0;
-    position-bottom: 0;
+    padding-top: 0;
+    padding-bottom: 0;
+    margin-top: 0;
+    margin-bottom: 0;
-GraphInspectorView > #resize-left {
+GraphInspectorView > .resize.horizontal {
-    background-color: rgba(0, 0, 0, 0);
-    position-type: absolute;
-    position-left: 0;
+    padding-right: 0;
+    margin-right: 0;
-GraphInspectorView > #resize-top {
-    cursor: resize-vertical;
-    background-color: rgba(0, 0, 0, 0);
-    position-type: absolute;
-    height: 10;
-    position-left: 0;
-    position-right: 0;
+GraphInspectorView > .resize.vertical.top {
-    padding-top: 0;
-    margin-top: 0;
+}
+
+GraphInspectorView > .resize.vertical.bottom {
+    position-bottom: 0;
-GraphInspectorView > #resize-bottom {
-    cursor: resize-vertical;
-    background-color: rgba(0, 0, 0, 0);
-    position-type: absolute;
-    height: 10;
+GraphInspectorView > .resize.horzontal.left {
+}
+
+GraphInspectorView > .resize.horizontal.right {
-    position-bottom: 0;
 }
 
 ShaderPropertyView {

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Drawing/Manipulators/ResizeSideHandle.cs

+using System;
+using UnityEngine;
+using UnityEngine.Experimental.UIElements;
+
+namespace UnityEditor.ShaderGraph.Drawing
+{
+    enum ResizeDirection
+    {
+        Any,
+        Vertical,
+        Horizontal
+    }
+
+    public enum ResizeHandleAnchor
+    {
+        Top,
+        Right,
+        Bottom,
+        Left
+    }
+
+    public class ResizeSideHandle : VisualElement
+    {
+        VisualElement m_ResizeTarget;
+
+        ResizeHandleAnchor m_HandleAnchor;
+
+        public ResizeSideHandle(VisualElement resizeTarget, ResizeHandleAnchor anchor, string[] styleClasses)
+        {
+            m_ResizeTarget = resizeTarget;
+
+            foreach (string styleClass in styleClasses)
+            {
+                AddToClassList(styleClass);
+            }
+
+            m_HandleAnchor = anchor;
+
+            ResizeDirection resizeDirection;
+
+            bool moveWhileResize = anchor == ResizeHandleAnchor.Top || anchor == ResizeHandleAnchor.Left;
+
+            if (anchor == ResizeHandleAnchor.Left || anchor == ResizeHandleAnchor.Right)
+            {
+                resizeDirection = ResizeDirection.Horizontal;
+            }
+            else
+            {
+                resizeDirection = ResizeDirection.Vertical;
+            }
+
+            this.AddManipulator(new Draggable(mouseDelta => OnResize(mouseDelta, resizeDirection, moveWhileResize)));
+        }
+
+        void OnResize(Vector2 resizeDelta, ResizeDirection direction, bool moveWhileResize)
+        {
+            Vector2 normalizedResizeDelta = resizeDelta / 2f;
+
+            if (direction == ResizeDirection.Vertical)
+            {
+                normalizedResizeDelta.x = 0f;
+            }
+            else if (direction == ResizeDirection.Horizontal)
+            {
+                normalizedResizeDelta.y = 0f;
+            }
+
+            Rect newLayout = m_ResizeTarget.layout;
+
+            // Resize form bottom/right
+            if (!moveWhileResize)
+            {
+                newLayout.width = Mathf.Max(m_ResizeTarget.layout.width + normalizedResizeDelta.x, 60f);
+                newLayout.height = Mathf.Max(m_ResizeTarget.layout.height + normalizedResizeDelta.y, 60f);
+
+                m_ResizeTarget.layout = newLayout;
+
+                return;
+            }
+
+            float previousFarX = m_ResizeTarget.layout.x + m_ResizeTarget.layout.width;
+            float previousFarY = m_ResizeTarget.layout.y + m_ResizeTarget.layout.height;
+
+            newLayout.width = Mathf.Max(m_ResizeTarget.layout.width - normalizedResizeDelta.x, 60f);
+            newLayout.height = Mathf.Max(m_ResizeTarget.layout.height - normalizedResizeDelta.y, 60f);
+
+            newLayout.x = Mathf.Min(m_ResizeTarget.layout.x + normalizedResizeDelta.x, previousFarX - 60f);
+            newLayout.y = Mathf.Min(m_ResizeTarget.layout.y + normalizedResizeDelta.y, previousFarY - 60f);
+
+            m_ResizeTarget.layout = newLayout;
+        }
+    }
+}

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Drawing/Manipulators/ResizeSideHandle.cs.meta

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