/// <summary>
    /// 對圖像進行點運算,
    /// </summary>
    public class PointTrans
    {
        private readonly double cb;
        private readonly double cg;
        private readonly double cr;

        /// <summary>
        /// 做點運算,要給每一個偏量,做一下設置,比如做圖像的灰度圖就需要現設置
        /// </summary>
        /// <param name="cr"></param>
        /// <param name="cg"></param>
        /// <param name="cb"></param>
        public PointTrans(double cr, double cg, double cb)
        {
            this.cr = cr;
            this.cg = cg;
            this.cb = cb;
        }

        public  Bitmap GrayScaleBmp(Bitmap orgData)
        {
            int bmpWidth = orgData.Width, bmpHeight = orgData.Height;
            Bitmap destData = ImageTools.CreateGrayscaleImage(bmpWidth, bmpHeight);
            Rectangle bmpRect=new Rectangle(0,0,bmpWidth,bmpHeight);

            BitmapData orgBmpData = orgData.LockBits(bmpRect, ImageLockMode.ReadOnly, PixelFormat.Format24bppRgb);

            BitmapData destBmpData = destData.LockBits(bmpRect, ImageLockMode.WriteOnly, PixelFormat.Format8bppIndexed);
            ProcessFilter(orgBmpData,destBmpData);

            orgData.UnlockBits(orgBmpData);
            destData.UnlockBits(destBmpData);
            return destData;

        }

        protected unsafe void ProcessFilter(BitmapData sourceData, BitmapData destinationData)
        {
            // get width and height
            int width = sourceData.Width;
            int height = sourceData.Height;

            int srcOffset = sourceData.Stride - width*3;
            int dstOffset = destinationData.Stride - width;

            // do the job
            byte* src = (byte*) sourceData.Scan0.ToPointer();
            byte* dst = (byte*) destinationData.Scan0.ToPointer();

            // for each line
            for (int y = 0; y < height; y++)
            {
                // for each pixel
                for (int x = 0; x < width; x++, src += 3, dst++)
                {
                    *dst = (byte) (cr*src[RGB.R] + cg*src[RGB.G] + cb*src[RGB.B]);
                }
                src += srcOffset;
                dst += dstOffset;
            }
        }

    }