using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Drawing;
using System.Drawing.Imaging;
using System.Runtime.InteropServices;

namespace 验证码处理
{
    class VerifyCode
    {
        public Bitmap bmpobj;

        public VerifyCode(Bitmap pic)
        {
            bmpobj = new Bitmap(pic);    //转换为Format32bppRgb
        }

        /// <summary>
        /// 根据RGB，计算灰度值
        /// </summary>
        /// <param name="posClr">Color值</param>
        /// <returns>灰度值，整型</returns>
        private int GetGrayNumColor(System.Drawing.Color posClr)
        {
            return (posClr.R * 19595 + posClr.G * 38469 + posClr.B * 7472) >> 16;
        }

        /// <summary>
        /// 灰度转换,逐点方式
        /// </summary>
        public void GrayByPixels()
        {
            for (int i = 0; i < bmpobj.Height; i++)
            {
                for (int j = 0; j < bmpobj.Width; j++)
                {
                    int tmpValue = GetGrayNumColor(bmpobj.GetPixel(j, i));
                    bmpobj.SetPixel(j, i, Color.FromArgb(tmpValue, tmpValue, tmpValue));
                }
            }
        }

        /// <summary>
        /// 去图形边框
        /// </summary>
        /// <param name="borderWidth"></param>
        public void ClearPicBorder(int borderWidth)
        {
            for (int i = 0; i < bmpobj.Height; i++)
            {
                for (int j = 0; j < bmpobj.Width; j++)
                {
                    if (i < borderWidth || j < borderWidth || j > bmpobj.Width - 1 - borderWidth || i > bmpobj.Height - 1 - borderWidth)
                        bmpobj.SetPixel(j, i, Color.FromArgb(255, 255, 255));
                }
            }
        }

        /// <summary>
        /// 灰度转换,逐行方式
        /// </summary>
        public void GrayByLine()
        {
            Rectangle rec = new Rectangle(0, 0, bmpobj.Width, bmpobj.Height);
            BitmapData bmpData = bmpobj.LockBits(rec, ImageLockMode.ReadWrite, bmpobj.PixelFormat);// PixelFormat.Format32bppPArgb);
            //    bmpData.PixelFormat = PixelFormat.Format24bppRgb;
            IntPtr scan0 = bmpData.Scan0;
            int len = bmpobj.Width * bmpobj.Height;
            int[] pixels = new int[len];
            Marshal.Copy(scan0, pixels, 0, len);

            //对图片进行处理
            int GrayValue = 0;
            for (int i = 0; i < len; i++)
            {
                GrayValue = GetGrayNumColor(Color.FromArgb(pixels[i]));
                pixels[i] = (byte)(Color.FromArgb(GrayValue, GrayValue, GrayValue)).ToArgb();      //Color转byte
            }

            bmpobj.UnlockBits(bmpData);

            ////输出
            //GCHandle gch = GCHandle.Alloc(pixels, GCHandleType.Pinned);
            //bmpOutput = new Bitmap(bmpobj.Width, bmpobj.Height, bmpData.Stride, bmpData.PixelFormat, gch.AddrOfPinnedObject());
            //gch.Free();
        }

        /// <summary>
        /// 得到有效图形并调整为可平均分割的大小
        /// </summary>
        /// <param name="dgGrayValue">灰度背景分界值</param>
        /// <param name="CharsCount">有效字符数</param>
        /// <returns></returns>
        public void GetPicValidByValue(int dgGrayValue, int CharsCount)
        {
            int posx1 = bmpobj.Width; int posy1 = bmpobj.Height;
            int posx2 = 0; int posy2 = 0;
            for (int i = 0; i < bmpobj.Height; i++)      //找有效区
            {
                for (int j = 0; j < bmpobj.Width; j++)
                {
                    int pixelValue = bmpobj.GetPixel(j, i).R;
                    if (pixelValue < dgGrayValue)     //根据灰度值
                    {
                        if (posx1 > j) posx1 = j;
                        if (posy1 > i) posy1 = i;

                        if (p