一个可以返回验证码图片的类库源码（C#）

验证码字符个数、生成图片宽度、高度自定均可由构造方法自定，无参构造生成默认字符个数和默认大小的Image,方法 GetImgWithValidateCode()返回生成的验证码图片，方法 IsRight(string inputValCode) 判断用户输入的验证码 inputValCode与图片显示的字符是否一致，不区分大小写


using System;


using System.IO;


using System.Data;


using System.Configuration;


using System.Collections;


using System.Drawing;


using System.Drawing.Imaging;


using System.Drawing.Drawing2D;



namespace DrawValidateImageLib


{


        public class DrawValImg


        {


                /// <summary>


                /// 无参构造


                /// </summary>


                public DrawValImg() { }


                /// <summary>


                /// 带有生成字符个数的构造


                /// </summary>


                /// <param name="charNum">验证码中包含随机字符的个数</param>


                public DrawValImg(int charNum)


                {


                        this.CharNum = charNum;


                }


                /// <summary>


                /// 带有验证码图片宽度和高度的构造


                /// </summary>


                /// <param name="width">验证码图片宽度</param>


                /// <param name="height">验证码图片高度</param>


                public DrawValImg(int width,int height)


                {


                        this.width = width;


                        this.height = height;


                }


                /// <summary>


                /// 带有生成字符个数，验证码图片宽度和高度的构造


                /// </summary>


                /// <param name="charNum">验证码中包含随机字符的个数</param>


                /// <param name="width">验证码图片宽度</param>


                /// <param name="height">验证码图片高度</param>


                public DrawValImg(int charNum,int width,int height)


                {


                        this.CharNum = charNum;


                        this.width = width;


                        this.height = height;


                }



                /// <summary>


                /// 验证码中字符个数


                /// </summary>


                int charNum = 5; //默认字符个数为5



                public int CharNum


                {


                        get { return charNum; }


                        set { charNum = value; }


                }


                /// <summary>


                /// 字号


                /// </summary>


                int fontSize = 20;



                public int FontSize


                {


                        get { return fontSize; }


                }


                /// <summary>


                /// 图片宽度


                /// </summary>


                int width=200;



                public int Width


                {


                        get { return width; }


                }



                /// <summary>


                /// 图片高度


                /// </summary>


                int height=45;



                public int Height


                {


                        get { return height; }


                        set { height = value; }


                }


                


                /// <summary>


                /// 随机生成的字符串


                /// </summary>


                string validStr="";



                public string ValidStr


                {


                        get { return validStr; }


                        set { validStr = value; }


                }



                /// <summary>


                /// 产生指定个数的随机字符串，默认字符个数为5


                /// </summary>


                void GetValidateCode()


                {


                        Random rd = new Random(); //创建随机数对象            



                        //产生由 charNum 个字母或数字组成的一个字符串


                        string str = "abcdefghijkmnpqrstuvwyzABCDEFGHJKLMNPQRSTUVWYZ23456789田国兴";//共57个字符，除 l,o,x,I,O,X,1,0 的所有数字和大写字母


                        for (int i = 0; i < charNum; i++)


                        {


                                validStr = validStr + str.Substring(rd.Next(57), 1);//返回0到56共57个


                        }


                        


                }


                


                /// <summary>


                /// 由随机字符串，随即颜色背景，和随机线条产生的Image


                /// </summary>


                /// <returns>Image</returns>


                public Image GetImgWithValidateCode()//返回 Image


                {


                        //产生随机字符串


                        GetValidateCode();



                        //声明一个位图对象


                        Bitmap bitMap = null;


                        //声明一个绘图画面


                        Graphics gph = null;


                        //创建内存流


                        MemoryStream memStream = new MemoryStream();


                        


                        Random random = new Random();


                        


                        //由给定的需要生成字符串中字符个数 CharNum， 图片宽度 Width 和高度 Height 确定字号 FontSize，


                        //确保不因字号过大而不能全部显示在图片上


                        int fontWidth=(int)Math.Round(width/(charNum+2)/1.3);


                        int fontHeight=(int)Math.Round(height/1.5);


                        //字号取二者中小者，以确保所有字符能够显示，并且字符的下半部分也能显示


                        fontSize = fontWidth <= fontHeight ? fontWidth : fontHeight;



                        //创建位图对象


                        bitMap = new Bitmap(width+FontSize,height);


                        //根据上面创建的位图对象创建绘图图面


                        gph = Graphics.FromImage(bitMap);



                        //设定验证码图片背景色


                        gph.Clear(GetControllableColor(200));


                        //产生随机干扰线条


                        for (int i = 0; i < 10; i++)


                        {


                                Pen backPen = new Pen(GetControllableColor(100), 2);


                                //线条起点


                                int x = random.Next(width);


                                int y = random.Next(height);


                                //线条终点


                                int x2 = random.Next(width);


                                int y2 = random.Next(height);


                                //划线


                                gph.DrawLine(backPen, x, y, x2, y2);


                        }



                        //定义一个含10种字体的数组


                        String[] fontFamily ={ "Arial", "Verdana", "Comic Sans MS", "Impact", "Haettenschweiler",


                                                "Lucida Sans Unicode", "Garamond", "Courier New", "Book Antiqua", "Arial Narrow" };


                        SolidBrush sb = new SolidBrush(GetControllableColor(0));


                        //通过循环,绘制每个字符,


                        for (int i = 0; i < validStr.Length; i++)


                        {


                                Font textFont = new Font(fontFamily[random.Next(10)], fontSize, FontStyle.Bold);//字体随机,字号大小30,加粗


                                


                                //每次循环绘制一个字符,设置字体格式,画笔颜色,字符相对画布的X坐标,字符相对画布的Y坐标


                                int space = (int)Math.Round((double)((width - fontSize * (CharNum + 2)) / CharNum));


                                //纵坐标


                                int y = (int)Math.Round((double)((height - fontSize)/3));


                                gph.DrawString(validStr.Substring(i, 1), textFont, sb, fontSize + i * (fontSize + space), y);


                        }


                        //扭曲图片


                        bitMap=TwistImage(bitMap, true, random.Next(3,5),random.Next(3));


                        


                        try


                        {


                                


                                bitMap.Save(memStream, ImageFormat.Gif);


                            


                        }


                        catch (Exception ex)


                        {


                                System.Windows.Forms.MessageBox.Show(ex.Message);


                        }


                        //gph.Dispose();


                        bitMap.Dispose();



                        Image img = Image.FromStream(memStream);


                        gph.DrawImage(img, 50, 20, width, 10);



                        return img;


                }


                /// <summary>


                /// 产生一种 R,G,B 均大于 colorBase 随机颜色，以确保颜色不会过深


                /// </summary>


                /// <returns>背景色</returns>


                Color GetControllableColor(int colorBase)


                {


                        Color color=Color.Black;


                        if (colorBase > 200)


                        {


                                System.Windows.Forms.MessageBox.Show("可控制颜色参数大于200，颜色默认位黑色");


                        }


                        Random random = new Random();


                        //确保 R,G,B 均大于 colorBase，这样才能保证背景色较浅


                         color= Color.FromArgb(random.Next(56) + colorBase, random.Next(56) + colorBase, random.Next(56) + colorBase);


                        return color;


                }



                /// <summary>


                /// 扭曲图片


                /// </summary>


                /// <param name="srcBmp"></param>


                /// <param name="bXDir"></param>


                /// <param name="dMultValue"></param>


                /// <param name="dPhase"></param>


                /// <returns></returns>


                Bitmap TwistImage(Bitmap srcBmp, bool bXDir, double dMultValue, double dPhase)


                {


                        int leftMargin = 0;


                        int rightMargin = 0;


                        int topMargin = 0;


                        int bottomMargin = 0;


                        //float PI = 3.14159265358979f;


                        float PI2 = 6.28318530717959f;


                        Bitmap destBmp = new Bitmap(srcBmp.Width, srcBmp.Height);


                        double dBaseAxisLen = bXDir ? Convert.ToDouble(destBmp.Height) : Convert.ToDouble(destBmp.Width);


                        for (int i = 0; i < destBmp.Width; i++)


                     {


                                for (int j = 0; j < destBmp.Height; j++)


                             {


                                        double dx = 0;


                                        dx = bXDir ? PI2 * Convert.ToDouble(j) / dBaseAxisLen : PI2 * Convert.ToDouble(i) / dBaseAxisLen;


                                        dx += dPhase;


                                        double dy = Math.Sin(dx);



                                        //取得当前点的颜色        


                                        int nOldX = 0;


                                        int nOldY = 0;


                                        nOldX = bXDir ? i + Convert.ToInt32(dy * dMultValue) : i;


                                        nOldY = bXDir ? j : j + Convert.ToInt32(dy * dMultValue);


                                        System.Drawing.Color color = srcBmp.GetPixel(i, j);


                                        if (nOldX >= leftMargin && nOldX < destBmp.Width - rightMargin && nOldY >= bottomMargin && nOldY < destBmp.Height - topMargin)


                                     {


                                                destBmp.SetPixel(nOldX, nOldY, color);


                                        }


                                }


                }


                return destBmp;


        }








                /// <summary>


                /// 判断验证码是否正确


                /// </summary>


                /// <param name="inputValCode">待判断的验证码</param>


                /// <returns>正确返回 true,错误返回 false</returns>


                public bool IsRight(string inputValCode)


                {



                        if (validStr.ToUpper().Equals(inputValCode.ToUpper()))//无论输入大小写都转换为大些判断


                        {


                                return true;


                        }


                        else


                        {


                                return false;


                        }


                }



        }


}

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