Make resize handels properly stay handle parent layout bounds (fixes #183)

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

             RegisterCallback<MouseUpEvent>(HandleDraggableMouseUp);
         }
 
-        void OnResize(Vector2 resizeDelta, ResizeDirection direction, bool moveWhileResizeHorizontal, bool moveWhileresizerVertical)
+        void OnResize(Vector2 resizeDelta, ResizeDirection direction, bool moveWhileResizeHorizontal, bool moveWhileresizeVertical)
         {
             Vector2 normalizedResizeDelta = resizeDelta / 2f;
 
 
             Rect newLayout = m_ResizeTarget.layout;
 
-            // Resize form bottom/right
+            // Resize from bottom/right
             if (!moveWhileResizeHorizontal)
             {
                 newLayout.width = Mathf.Max(newLayout.width + normalizedResizeDelta.x, minSize.x);
-            if (!moveWhileresizerVertical)
+            if (!moveWhileresizeVertical)
             {
                 newLayout.height = Mathf.Max(newLayout.height + normalizedResizeDelta.y, minSize.y);
                 normalizedResizeDelta.y = 0f;
 
             if (m_StayWithinParentBounds)
             {
-                if (newLayout.x < 0f || (newLayout.x + newLayout.width) > m_ResizeTarget.parent.layout.width)
+                float horizontalTranscendance = Mathf.Min(newLayout.x, 0f) + Mathf.Max(newLayout.xMax - m_ResizeTarget.parent.layout.width, 0f);
+                float verticalTranscendance = Mathf.Min(newLayout.y, 0f) + Mathf.Max(newLayout.yMax - m_ResizeTarget.parent.layout.height, 0f);
+
+                if (moveWhileResizeHorizontal)
-                    newLayout.width = m_ResizeTarget.layout.width;
+                    newLayout.x -= horizontalTranscendance;
+                newLayout.width -= Mathf.Abs(horizontalTranscendance);
-                if (newLayout.y < 0f || (newLayout.y + newLayout.height) > m_ResizeTarget.parent.layout.height)
+                if (moveWhileresizeVertical)
-                    newLayout.height = m_ResizeTarget.layout.height;
+                    newLayout.y -= verticalTranscendance;
+                newLayout.height -= Mathf.Abs(verticalTranscendance);
             }
 
             m_ResizeTarget.layout = newLayout;