WPF - Workaround for Cursors not loading correctly

- For cursors that are embedded in libcef.dll the OnCursorChange method is passing
 in IntPtr.Zero so we're unable to load the cursor.
 This commit adds a manual mapping of CursorType to resource Id and loads the cursors manually
- Adds a basic test to assert the cursors load, should validate if the resource ids change

This needs to be fixed upstream https://bitbucket.org/chromiumembedded/cef/issues/3270/osr-pan-icon-missing-when-pressing-the

Test url https://developer.mozilla.org/en-US/docs/Web/CSS/cursor#values

Issue #4021

Author: amaitland

CefSharp.Core.Runtime/NativeMethodWrapper.cpp

@@ -60,5 +60,23 @@ namespace CefSharp
                 SetWindowLongPtr(hwnd, GWL_EXSTYLE, exStyle & ~WS_EX_NOACTIVATE);
             }
         }
+
+        IntPtr NativeMethodWrapper::LoadCursorFromLibCef(int resourceIdentifier)
+        {
+            auto moduleName = L"libcef.dll";
+
+            HMODULE hModule = GetModuleHandle(moduleName);
+
+            if (hModule == nullptr)
+            {
+                return IntPtr::Zero;
+            }
+
+            auto lpCursorName = MAKEINTRESOURCE(resourceIdentifier);
+
+            auto cursor = LoadCursor(hModule, lpCursorName);
+
+            return static_cast<IntPtr>(cursor);
+        }        
     }
 }

CefSharp.Core.Runtime/NativeMethodWrapper.h

@@ -23,6 +23,7 @@ namespace CefSharp
             static void SetWindowPosition(IntPtr handle, int x, int y, int width, int height);
             static void SetWindowParent(IntPtr child, IntPtr newParent);
             static void RemoveExNoActivateStyle(IntPtr browserHwnd);
+            static IntPtr LoadCursorFromLibCef(int resourceIdentifier);
         };
     }
 }

CefSharp.Core/NativeMethodWrapper.cs

@@ -38,5 +38,10 @@ public static void RemoveExNoActivateStyle(IntPtr browserHwnd)
         {
             CefSharp.Core.NativeMethodWrapper.RemoveExNoActivateStyle(browserHwnd);
         }
+
+        public static IntPtr LoadCursorFromLibCef(int resourceIdentifier)
+        {
+            return CefSharp.Core.NativeMethodWrapper.LoadCursorFromLibCef(resourceIdentifier);
+        }
     }
 }

CefSharp.Test/Wpf/EmbeddedCursorLoadTests.cs

@@ -0,0 +1,50 @@
+// Copyright © 2022 The CefSharp Authors. All rights reserved.
+//
+// Use of this source code is governed by a BSD-style license that can be found in the LICENSE file.
+
+using System;
+using CefSharp.Enums;
+using CefSharp.Wpf.Internals;
+using Xunit;
+
+namespace CefSharp.Test.Wpf
+{
+    //NOTE: All Test classes must be part of this collection as it manages the Cef Initialize/Shutdown lifecycle
+    /// <summary>
+    /// Issue #4021
+    /// Validate Cursor resource Ids
+    /// </summary>
+    [Collection(CefSharpFixtureCollection.Key)]
+    public class EmbeddedCursorLoadTests
+    {
+        [Theory]
+        [InlineData(CursorType.Alias)]
+        [InlineData(CursorType.Cell)]
+        [InlineData(CursorType.ColumnResize)]
+        [InlineData(CursorType.Copy)]
+        [InlineData(CursorType.Grab)]
+        [InlineData(CursorType.Grabbing)]
+        [InlineData(CursorType.EastPanning)]
+        [InlineData(CursorType.MiddlePanning)]
+        [InlineData(CursorType.MiddlePanningHorizontal)]
+        [InlineData(CursorType.MiddlePanningVertical)]
+        [InlineData(CursorType.NorthPanning)]
+        [InlineData(CursorType.NortheastPanning)]
+        [InlineData(CursorType.NorthwestPanning)]
+        [InlineData(CursorType.SouthPanning)]
+        [InlineData(CursorType.SoutheastPanning)]
+        [InlineData(CursorType.SouthwestPanning)]
+        [InlineData(CursorType.WestPanning)]
+        [InlineData(CursorType.RowResize)]
+        [InlineData(CursorType.VerticalText)]
+        [InlineData(CursorType.ZoomIn)]
+        [InlineData(CursorType.ZoomOut)]
+        public void CanGetEmbeddedCursors(CursorType cursorType)
+        {
+            var actual = EmbeddedCursor.TryLoadCursor(cursorType, out IntPtr cursorPtr);
+
+            Assert.True(actual);
+            Assert.NotEqual(IntPtr.Zero, cursorPtr);
+        }
+    }
+}

CefSharp.Wpf/ChromiumWebBrowser.cs

@@ -1007,7 +1007,16 @@ protected virtual void OnCursorChange(IntPtr handle, CursorType type, CursorInfo
             {
                 UiThreadRunAsync(() =>
                 {
-                    Cursor = CursorInteropHelper.Create(new SafeFileHandle(handle, ownsHandle: false));
+                    //Workaround for upstream issue
+                    //See #4021
+                    if (EmbeddedCursor.TryLoadCursor(type, out IntPtr cursorHandle))
+                    {
+                        Cursor = CursorInteropHelper.Create(new SafeFileHandle(cursorHandle, ownsHandle: false));
+                    }
+                    else
+                    {
+                        Cursor = CursorInteropHelper.Create(new SafeFileHandle(handle, ownsHandle: false));
+                    }
                 });
             }
         }

CefSharp.Wpf/Internals/EmbeddedCursor.cs

@@ -0,0 +1,85 @@
+// Copyright © 2022 The CefSharp Authors. All rights reserved.
+//
+// Use of this source code is governed by a BSD-style license that can be found in the LICENSE file.
+
+using System;
+using System.Collections.Generic;
+using CefSharp.Enums;
+
+namespace CefSharp.Wpf.Internals
+{
+    // Workaround for upstream issue
+    // It's possible resources Ids might change between versions, so this might need to be updated
+    // for different builds, will need to test after upgrading
+    // See #4021
+    public static class EmbeddedCursor
+    {
+        //const int IDC_ALIAS = 35610;
+        //const int IDC_CELL = 35611;
+        //const int IDC_COLRESIZE = 35612;
+        //const int IDC_COPYCUR = 35613;
+        //const int IDC_HAND_GRAB = 35614;
+        //const int IDC_HAND_GRABBING = 35615;
+        //const int IDC_PAN_EAST = 35616;
+        //const int IDC_PAN_MIDDLE = 35617;
+        //const int IDC_PAN_MIDDLE_HORIZONTAL = 35618;
+        //const int IDC_PAN_MIDDLE_VERTICAL = 35619;
+        //const int IDC_PAN_NORTH = 35620;
+        //const int IDC_PAN_NORTH_EAST = 35621;
+        //const int IDC_PAN_NORTH_WEST = 35622;
+        //const int IDC_PAN_SOUTH = 35623;
+        //const int IDC_PAN_SOUTH_EAST = 35624;
+        //const int IDC_PAN_SOUTH_WEST = 35625;
+        //const int IDC_PAN_WEST = 35626;
+        //const int IDC_ROWRESIZE = 35627;
+        //const int IDC_VERTICALTEXT = 35628;
+        //const int IDC_ZOOMIN = 35629;
+        //const int IDC_ZOOMOUT = 35630;
+
+        private static Dictionary<CursorType, int> EmbeddedCursors = new Dictionary<CursorType, int>
+        {
+            { CursorType.Alias, 35610 },
+            { CursorType.Cell, 35611 },
+            { CursorType.ColumnResize, 35612 },
+            { CursorType.Copy, 35613 },
+            { CursorType.Grab, 35614 },
+            { CursorType.Grabbing, 35615 },
+            { CursorType.EastPanning, 35616 },
+            { CursorType.MiddlePanning, 35617 },
+            { CursorType.MiddlePanningHorizontal, 35618 },
+            { CursorType.MiddlePanningVertical, 35619 },
+            { CursorType.NorthPanning, 35620 },
+            { CursorType.NortheastPanning, 35621 },
+            { CursorType.NorthwestPanning, 35622 },
+            { CursorType.SouthPanning, 35623 },
+            { CursorType.SoutheastPanning, 35624 },
+            { CursorType.SouthwestPanning, 35625 },
+            { CursorType.WestPanning, 35626 },
+            { CursorType.RowResize, 35627 },
+            { CursorType.VerticalText, 35628 },
+            { CursorType.ZoomIn, 35629 },
+            { CursorType.ZoomOut, 35630 }
+        };
+
+        public static bool TryLoadCursor(CursorType cursorType, out IntPtr cursor)
+        {
+            cursor = IntPtr.Zero;
+
+            try
+            {
+                if (EmbeddedCursors.TryGetValue(cursorType, out int key))
+                {
+                    cursor = NativeMethodWrapper.LoadCursorFromLibCef(key);
+
+                    return cursor != IntPtr.Zero;
+                }
+            }
+            catch (Exception)
+            {
+
+            }
+
+            return false;
+        }
+    }
+}