Workaround sRGB issue in UIElements such that previews are now rendered correctly

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

         AbstractNodeEditorView m_EditorView;
 
         TypeMapper m_TypeMapper;
-        Image m_Preview;
+        PreviewView m_Preview;
 
         AbstractMaterialGraph m_Graph;
         PreviewSystem m_PreviewSystem;
                     bottomContainer.Add(layersContainer);
                 }
 
-                m_Preview = new Image {name = "preview", image = Texture2D.blackTexture};
+                m_Preview = new PreviewView {name = "preview", image = Texture2D.blackTexture};
                 bottomContainer.Add(m_Preview);
             }
             Add(bottomContainer);

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Drawing/Views/MaterialNodeView.cs

     {
         List<VisualElement> m_ControlViews;
         PreviewData m_Preview;
-        Image m_PreviewImage;
+        PreviewView m_PreviewImage;
         VisualElement m_PreviewToggle;
         VisualElement m_ControlsContainer;
 
             previewExpanded = node.previewExpanded;
             leftContainer.Add(m_PreviewToggle);
 
-            m_PreviewImage = new Image
+            m_PreviewImage = new PreviewView
             {
                 name = "preview",
                 pickingMode = PickingMode.Ignore,
 
                 UpdateSize();
             }
+
+            clippingOptions = ClippingOptions.ClipContents;
         }
 
         public AbstractMaterialNode node { get; private set; }

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Resources/Shaders/Checkerboard.shader

             static const float rows = 32;
             static const float columns = 32;
 
-            static const float4 col1 = float4(0.389297, 0.389297, 0.389297, 1.0);
-            static const float4 col2 = float4(0.442601, 0.442601, 0.442601, 1.0);
+            static const float4 col1 = float4(32.0/255.0, 32.0/255.0, 32.0/255.0, 1.0);
+            static const float4 col2 = float4(42.0/255.0, 42.0/255.0, 42.0/255.0, 1.0);
 
             float4 frag(v2f_img i) : COLOR
             {

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Drawing/Views/PreviewView.cs

+using UnityEngine;
+using UnityEngine.Experimental.UIElements;
+using UnityEngine.Rendering;
+
+namespace UnityEditor.MaterialGraph.Drawing
+{
+    public sealed class PreviewView : VisualElement
+    {
+        Texture m_Image;
+
+        public Texture image
+        {
+            get { return m_Image; }
+            set
+            {
+                if (value == m_Image)
+                    return;
+                m_Image = value;
+                Dirty(ChangeType.Repaint);
+            }
+        }
+
+        public override void DoRepaint()
+        {
+            EditorGUI.DrawPreviewTexture(contentRect, image);
+        }
+    }
+}

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Drawing/Views/PreviewView.cs.meta

+fileFormatVersion: 2
+guid: 524b1aa8d68043cd81a6514d805eb50d
+timeCreated: 1508917442