在Windows Phone 8中将图像转换为灰度

Question

如何在Windows Phone 8中将普通图像转换为灰度图像.在WritableBitmapEx中是否有任何灰度转换的规定.

Answer 1

try this extension method...

public static WriteableBitmap ToGrayScale(this WriteableBitmap bitmapImage)
{

    for (var y = 0; y < bitmapImage.PixelHeight; y++)
    {
        for (var x = 0; x < bitmapImage.PixelWidth; x++)
        {
            var pixelLocation = bitmapImage.PixelWidth * y + x;
            var pixel = bitmapImage.Pixels[pixelLocation];
            var pixelbytes = BitConverter.GetBytes(pixel);
            var bwPixel = (byte)(.299 * pixelbytes[2] + .587 * pixelbytes[1] + .114 * pixelbytes[0]);
            pixelbytes[0] = bwPixel;
            pixelbytes[1] = bwPixel;
            pixelbytes[2] = bwPixel;
            bitmapImage.Pixels[pixelLocation] = BitConverter.ToInt32(pixelbytes, 0);
        }
    }

    return bitmapImage;
}