问如何着色图像@ Windows-10地铁应用程序？

EN

private static async void changeImage(Molecule molecule)
{
    Molecule.Reaction++;    // Used as Working/Loading status here
    var atoms = molecule.Atoms;
    if (atoms > 5) atoms = 5;

    var stream = await GetStream("Assets/Images/" + atoms + ".png");
    var decoder = await BitmapDecoder.CreateAsync(stream); 
    var pixelData = await decoder.GetPixelDataAsync();
    var data = pixelData.DetachPixelData(); // Finally something where I can get my pixels

    var wb = new WriteableBitmap(16, 16);
    //wb.SetSource(stream);     // Get pixel not working so I dont need this

    for(int y = 0; y < decoder.PixelHeight; y++)
    {
        for(int x = 0; x < decoder.PixelWidth; x++)
        {
            // var rgba = wb.GetPixel(x, y);    // This is not working, only returnning empty pixels (A:0, R:0, G:0, B:0)

            // Get RGBA value of pixel
            var rgba = new Color {
                R = data[x * 4 + y * decoder.PixelWidth * 4 + 0],
                G = data[x * 4 + y * decoder.PixelWidth * 4 + 1],
                B = data[x * 4 + y * decoder.PixelWidth * 4 + 2],
                A = data[x * 4 + y * decoder.PixelWidth * 4 + 3]
            };

            // Array can't have index -1 and -1 is for gray what is default
            if (molecule.Owner != -1)
            {
                // Colorize pixel
                var z = ((rgba.R + rgba.G + rgba.B) / 3.0) / 256;
                rgba.R = Convert.ToByte(z * Settings.Colors[molecule.Owner].Item1.Color.R);
                rgba.G = Convert.ToByte(z * Settings.Colors[molecule.Owner].Item1.Color.G);
                rgba.B = Convert.ToByte(z * Settings.Colors[molecule.Owner].Item1.Color.B);
                data[x * 4 + y * decoder.PixelWidth * 4 + 0] = rgba.R;
                data[x * 4 + y * decoder.PixelWidth * 4 + 1] = rgba.G;
                data[x * 4 + y * decoder.PixelWidth * 4 + 2] = rgba.B;
            }

            wb.SetPixel(x, y, rgba); // I tried to connect byte[] and WriteAbleBitmap via stream but Failed so I'm using this
        }
    }

    if (atoms == molecule.Atoms)    // Because it's async method so If value is already different don't change it to old picture
    {
        molecule.parent.Content = new Image();
        (molecule.parent.Content as Image).Source = wb;
        (molecule.parent.Content as Image).Width = 24;
        (molecule.parent.Content as Image).Height = 24;
    }

    Molecule.Reaction--;    // done changing picture
}

internal static async Task<IRandomAccessStream> GetStream(string relativePath)
{
    var storageFile = await Package.Current.InstalledLocation.GetFileAsync(relativePath.Replace('/', '\\'));
    var stream = await storageFile.OpenReadAsync();
    return stream;
}