月更

AntDesignWPF/Converters/BackgroundToForegroundConverter.cs

@@ -0,0 +1,60 @@
+namespace AntDesign.WPF.Converters
+{
+    using System;
+    using System.Globalization;
+    using System.Linq;
+    using System.Windows;
+    using System.Windows.Data;
+    using System.Windows.Media;
+
+    public class BackgroundToForegroundConverter : IValueConverter, IMultiValueConverter
+    {
+        public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
+        {
+            if (value is SolidColorBrush)
+            {
+                var brush = new SolidColorBrush(GetIdealColor(((SolidColorBrush)value).Color));
+                brush.Freeze();
+                return brush;
+            }
+
+            return Brushes.White;
+        }
+
+        public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
+        {
+            return DependencyProperty.UnsetValue;
+        }
+
+        public object Convert(object[] values, Type targetType, object parameter, CultureInfo culture)
+        {
+            var bgBrush = values.Length > 0 ? values[0] as Brush : null;
+            var titleBrush = values.Length > 1 ? values[1] as Brush : null;
+
+            if (titleBrush != null)
+            {
+                return titleBrush;
+            }
+
+            return Convert(bgBrush, targetType, parameter, culture);
+        }
+
+        public object[] ConvertBack(object value, Type[] targetTypes, object parameter, CultureInfo culture)
+        {
+            return targetTypes.Select(t => DependencyProperty.UnsetValue).ToArray();
+        }
+
+        /// <summary>
+        /// Determining Ideal Text Color Based on Specified Background Color
+        /// http://www.codeproject.com/KB/GDI-plus/IdealTextColor.aspx
+        /// </summary>
+        /// <param name="color">background color</param>
+        /// <param name="threshold"></param>
+        /// <returns></returns>
+        private Color GetIdealColor(Color color,int threshold = 86)
+        {
+            var delta = System.Convert.ToInt32((color.R * 0.299) + (color.G * 0.587) + (color.B * 0.114));
+            return  (255 - delta < threshold) ? Colors.Black : Colors.White;
+        }
+    }
+}