CODEWITHSUNDEEP
c#wpfwindows-8
emoacht
emoacht

Reputation: 3556

How to get title bar color of WPF window in Windows 8.1?

To customize window's appearance using WindowChrome class, I would like to get the title bar color of WPF window in Windows 8.1.

First, I tried 

SystemParameters.WindowGlassColor

But this property but does not include correct alpha value (it is always 255).

Second, I tried the function:

DwmGetColorizationColor

It seemed to work fine at first. The return value has correct color information including alpha channel. However, as changing "Color intensity" by slide bar in "Color and Appearance" dialog, the return value will go away from the actual one and indicate a weird color.

So, does anyone have idea on alternate method or workaround?

Upvotes: 3

Views: 3047

Answers (1)

emoacht
emoacht

Reputation: 3556

I found a solution. Actually, the basic point has been already discussed.

The sequence will be:

  1. Get parameters by DwmGetColorizationParameters function (undocumented API).
  2. Convert colorizationColor parameter to Color ignoring alpha channel.
  3. Prepare base gray color (R=217, G=217, B=217).
  4. Blend the two colors using colorizationColorBalance parameter which corresponds to "Color Intensity".

So, my code is as follows:

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));
}

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);
}

[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;
}

Upvotes: 9

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