Asp.net(C#)-彩色圖片轉化為黑白

    /// <summary> 
    /// 彩色圖片轉化為黑白 
    /// </summary> 
    /// <param name="source"></param> 
    /// <returns></returns> 
    public static Bitmap ConvertToGrayscale(Bitmap bitmap) 
    { 
        Bitmap bm = new Bitmap(bitmap.Width, bitmap.Height); 
        for (int y = 0; y < bm.Height; y++) 
        { 
            for (int x = 0; x < bm.Width; x++) 
            { 
                Color c = bitmap.GetPixel(x, y); 
                int rgb = (int)(c.R * 0.3 + c.G * 0.59 + c.B * 0.11); 
                bm.SetPixel(x, y, Color.FromArgb(rgb, rgb, rgb)); 
            } 
        } 
        return bm; 
    }