Get window's chome color (title bar color) in Windows 8.1.

WindowsEightChromeColor.cs

using System;
using System.Runtime.InteropServices;
using System.Windows.Media;

public static class WindowsEightChromeColor
{
	public static Color? GetChromeColor()
	{
		bool isEnabled;
		var hr1 = DwmIsCompositionEnabled(out isEnabled);
		if ((hr1 != 0) || !isEnabled) // 0 means S_OK.
			return null;

		DWMCOLORIZATIONPARAMS parameters;
		try
		{
			// This API is undocumented and so may become unusable in future versions of OSes.
			var hr2 = DwmGetColorizationParameters(out parameters);
			if (hr2 != 0) // 0 means S_OK.
				return null;
		}
		catch
		{
			return null;
		}

		// Convert colorization color parameter to Color ignoring alpha channel.
		var targetColor = Color.FromRgb(
			(byte)(parameters.colorizationColor >> 16),
			(byte)(parameters.colorizationColor >> 8),
			(byte)parameters.colorizationColor);

		// Prepare base gray color.
		var baseColor = Color.FromRgb(217, 217, 217);

		// Blend the two colors using colorization color balance parameter.
		return BlendColor(targetColor, baseColor, (double)(100 - parameters.colorizationColorBalance));
	}


	#region Helper

	private static Color BlendColor(Color color1, Color color2, double color2Perc)
	{
		if ((color2Perc < 0) || (100 < color2Perc))
			throw new ArgumentOutOfRangeException("color2Perc");

		return Color.FromRgb(
			BlendColorChannel(color1.R, color2.R, color2Perc),
			BlendColorChannel(color1.G, color2.G, color2Perc),
			BlendColorChannel(color1.B, color2.B, color2Perc));
	}

	private static byte BlendColorChannel(double channel1, double channel2, double channel2Perc)
	{
		var buff = channel1 + (channel2 - channel1) * channel2Perc / 100D;
		return Math.Min((byte)Math.Round(buff), (byte)255);
	}

	#endregion


	#region Win32

	[DllImport("Dwmapi.dll")]
	private static extern int DwmIsCompositionEnabled([MarshalAs(UnmanagedType.Bool)] out bool pfEnabled);

	[DllImport("Dwmapi.dll", EntryPoint = "#127")] // Undocumented API
	private static extern int DwmGetColorizationParameters(out DWMCOLORIZATIONPARAMS parameters);

	[StructLayout(LayoutKind.Sequential)]
	private struct DWMCOLORIZATIONPARAMS
	{
		public uint colorizationColor;
		public uint colorizationAfterglow;
		public uint colorizationColorBalance; // Ranging from 0 to 100
		public uint colorizationAfterglowBalance;
		public uint colorizationBlurBalance;
		public uint colorizationGlassReflectionIntensity;
		public uint colorizationOpaqueBlend;
	}

	#endregion
}