1 files changed, 65 insertions, 0 deletions

diff --git a/src/WixToolset.WixBA/WindowProperties.cs b/src/WixToolset.WixBA/WindowProperties.cs
new file mode 100644
index 00000000..bead5cc1
--- /dev/null
+++ b/src/WixToolset.WixBA/WindowProperties.cs
@@ -0,0 +1,65 @@
+// Copyright (c) .NET Foundation and contributors. All rights reserved. Licensed under the Microsoft Reciprocal License. See LICENSE.TXT file in the project root for full license information.
+
+namespace WixToolset.UX
+{
+    using System;
+    using System.Windows;
+    using System.Windows.Media;
+
+    /// <summary>
+    /// Dependency Properties associated with the main Window object.
+    /// </summary>
+    public class WindowProperties : DependencyObject
+    {
+        /// <summary>
+        /// Dependency Property to hold the result of detecting the relative luminosity (or brightness) of a Windows background.
+        /// </summary>
+        public static readonly DependencyProperty IsLightBackgroundProperty = DependencyProperty.Register(
+            "IsLightBackground", typeof(bool), typeof(WindowProperties), new PropertyMetadata( false ));
+
+        private static Lazy<WindowProperties> _instance = new Lazy<WindowProperties>(() =>
+        {
+            WindowProperties wp = new WindowProperties();
+            wp.CheckBackgroundBrightness();
+            return wp;
+        });
+
+        public static WindowProperties Instance
+        {
+            get
+            {
+                return _instance.Value;
+            }
+        }
+
+
+        public bool IsLightBackground
+        {
+            get { return (bool)GetValue(IsLightBackgroundProperty); }
+            private set { SetValue(IsLightBackgroundProperty, value); }
+        }
+
+        /// <summary>
+        /// Use the Luminosity parameter of the background color to detect light vs dark theme settings.
+        /// </summary>
+        /// <remarks>
+        /// This approach detects both the common High Contrast themes (White vs Black) and custom themes which may have relatively lighter backgrounds.
+        /// </remarks>
+        public void CheckBackgroundBrightness()
+        {
+            SolidColorBrush windowbrush = System.Windows.SystemColors.WindowBrush;
+            System.Drawing.Color dcolor = System.Drawing.Color.FromArgb(windowbrush.Color.A, windowbrush.Color.R, windowbrush.Color.G, windowbrush.Color.B);
+
+            var brightness = dcolor.GetBrightness();
+            // Test for 'Lightness' at an arbitrary point, approaching 1.0 (White).           
+            if (0.7 < brightness)
+            {
+                this.IsLightBackground = true;
+            }
+            else
+            {
+                this.IsLightBackground = false;
+            }
+        }
+    }
+}