随机图片生成器制作方法分享

/// <summary>
    /// pichandler1 的摘要说明
    /// </summary>
    public class pichandler1 : ihttphandler, irequiressessionstate
    {
        private string mcheckno = string.empty;
        protected imgbuilder _imgbuilder = new imgbuilder();
        protected vryimggen _imgbuildernew = new vryimggen();
        private string _text = string.empty;
        private string _font = "宋体";
        private int _fontsize = 8;
        private int _padding = 2;
        public void processrequest(httpcontext context)
        {
            mcheckno = discheckno();
            context.session["checkcode"] = mcheckno;
            this._imgbuilder.fontsize = this._fontsize;
            this._imgbuilder.padding = this._padding;

            if (!string.isnullorempty(this._font))
            {
                this._imgbuilder.fonts = new string[] { this._font };
            }
            this._imgbuildernew.chaoswight = 40;
            this._imgbuildernew.fontsize = 25;

            this._imgbuildernew.padding = 3;
            system.drawing.bitmap image =
             this._imgbuildernew.createimage(mcheckno);
            system.io.memorystream ms = new system.io.memorystream();
            image.save(ms, system.drawing.imaging.imageformat.jpeg);
            context.response.clearcontent();
            context.response.contenttype = "image/jpeg";
            context.response.binarywrite(ms.toarray());
            context.session["checkcode"] = mcheckno.tostring(); //如果没有实现irequiressessionstate，则这里会出错，也无法生成图片
            context.response.end();
        }

        //验证码生成
        protected string discheckno()
        {
            string hash = hashcode.getnext();
            string checkno = string.empty;
            random rd = new random(datetime.now.millisecond);
            for (int i = 0; i < 6; i++)
            {
                checkno += hash.substring(rd.next(1, hash.length - 1), 1);
            }
            checkno = checkno.replace("0", rd.next(1, 9).tostring());
            checkno = checkno.replace("o", rd.next(1, 9).tostring());
            checkno = checkno.replace("o", rd.next(1, 9).tostring());
            return checkno;
        }

        public bool isreusable
        {
            get
            {
                return false;
            }
        }
    }

using system;
using system.drawing;
using system.text;

/// <summary>
/// vryimggen 的摘要说明
/// </summary>
public class vryimggen
{
    public static string chinesechars = string.empty;

    /// <summary>
    /// 英文与数字串
    /// </summary>
    protected static readonly string englishornumchars = "0123456789abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz";

    public vryimggen()
    {
        rnd = new random(unchecked((int)datetime.now.ticks));
    }

    /// <summary>
    /// 全局随机数生成器
    /// </summary>
    private random rnd;

    int length = 5;
    /// <summary>
    /// 验证码长度(默认6个验证码的长度)
    /// </summary>
    public int length
    {
        get { return length; }
        set { length = value; }
    }

    int fontsize = 20;
    /// <summary>
    /// 验证码字体大小(为了显示扭曲效果，默认30像素，可以自行修改)
    /// </summary>
    public int fontsize
    {
        get { return fontsize; }
        set { fontsize = value; }
    }

    int padding = 4;
    /// <summary>
    /// 边框补(默认4像素)
    /// </summary>
    public int padding
    {
        get { return padding; }
        set { padding = value; }
    }

    bool chaos = true;
    /// <summary>
    /// 是否输出燥点(默认输出)
    /// </summary>
    public bool chaos
    {
        get { return chaos; }
        set { chaos = value; }
    }

    color chaoscolor = color.lightgray;
    /// <summary>
    /// 输出燥点的颜色(默认灰色)
    /// </summary>
    public color chaoscolor
    {
        get { return chaoscolor; }
        set { chaoscolor = value; }
    }

    int chaoswight = 1;
    /// <summary>
    /// 输出燥点的浓度
    /// </summary>
    public int chaoswight
    {
        get { return chaoswight; }
        set { chaoswight = value; }
    }

    color backgroundcolor = color.white;
    /// <summary>
    /// 自定义背景色(默认白色)
    /// </summary>
    public color backgroundcolor
    {
        get { return backgroundcolor; }
        set { backgroundcolor = value; }
    }

    color[] colors = { color.black, color.red, color.darkblue, color.green, color.orange, color.brown, color.darkcyan, color.purple };
    /// <summary>
    /// 自定义随机颜色数组
    /// </summary>
    public color[] colors
    {
        get { return colors; }
        set { colors = value; }
    }

    string[] fonts = { "arial", "georgia" };
    /// <summary>
    /// 自定义字体数组
    /// </summary>
    public string[] fonts
    {
        get { return fonts; }
        set { fonts = value; }
    }

    #region 产生波形滤镜效果

    private const double pi = 3.1415926535897932384626433832795;
    private const double pi2 = 6.283185307179586476925286766559;

    /// <summary>
    /// 正弦曲线wave扭曲图片（edit by 51aspx.com）
    /// </summary>
    /// <param name="srcbmp">图片路径</param>
    /// <param name="bxdir">如果扭曲则选择为true</param>
    /// <param name="nmultvalue">波形的幅度倍数，越大扭曲的程度越高，一般为3</param>
    /// <param name="dphase">波形的起始相位，取值区间[0-2*pi)</param>
    /// <returns></returns>
    public system.drawing.bitmap twistimage(bitmap srcbmp, bool bxdir, double dmultvalue, double dphase)
    {
        system.drawing.bitmap destbmp = new bitmap(srcbmp.width, srcbmp.height);

        // 将位图背景填充为白色
        system.drawing.graphics graph = system.drawing.graphics.fromimage(destbmp);
        graph.fillrectangle(new solidbrush(system.drawing.color.white), 0, 0, destbmp.width, destbmp.height);
        graph.dispose();

        double dbaseaxislen = bxdir ? (double)destbmp.height : (double)destbmp.width;

        for (int i = 0; i < destbmp.width; i++)
        {
            for (int j = 0; j < destbmp.height; j++)
            {
                double dx = 0;
                dx = bxdir ? (pi2 * (double)j) / dbaseaxislen : (pi2 * (double)i) / dbaseaxislen;
                dx += dphase;
                double dy = math.sin(dx);

                // 取得当前点的颜色
                int noldx = 0, noldy = 0;
                noldx = bxdir ? i + (int)(dy * dmultvalue) : i;
                noldy = bxdir ? j : j + (int)(dy * dmultvalue);

                system.drawing.color color = srcbmp.getpixel(i, j);
                if (noldx >= 0 && noldx < destbmp.width
                 && noldy >= 0 && noldy < destbmp.height)
                {
                    destbmp.setpixel(noldx, noldy, color);
                }
            }
        }

        return destbmp;
    }

 

    #endregion

    /// <summary>
    /// 生成校验码图片
    /// </summary>
    /// <param name="code">验证码</param>
    /// <returns></returns>
    public bitmap createimage(string code)
    {
        int fsize = fontsize;
        int fwidth = fsize + padding;

        int imagewidth = (int)(code.length * fwidth) + 4 + padding * 2;
        int imageheight = fsize * 2 + padding * 2;

        system.drawing.bitmap image = new system.drawing.bitmap(imagewidth - 10, imageheight - 10);

        graphics g = graphics.fromimage(image);

        g.clear(backgroundcolor);

        //给背景添加随机生成的燥点
        if (this.chaos)
        {

            pen pen = new pen(chaoscolor, 0);
            int c = chaoswight * 10;

            for (int i = 0; i < c; i++)
            {
                int x = rnd.next(image.width);
                int y = rnd.next(image.height);

                g.drawrectangle(pen, x, y, 1, 1);
            }
        }

        int left = 0, top = 0, top1 = 1, top2 = 1;

        int n1 = (imageheight - fontsize - padding * 2);
        int n2 = n1 / 4;
        top1 = n2;
        top2 = n2 * 2;

        font f;
        brush b;

        int cindex, findex;

        //随机字体和颜色的验证码字符
        for (int i = 0; i < code.length; i++)
        {
            cindex = rnd.next(colors.length - 1);
            findex = rnd.next(fonts.length - 1);

            f = new system.drawing.font(fonts[findex], fsize, system.drawing.fontstyle.bold);
            b = new system.drawing.solidbrush(colors[cindex]);

            if (i % 2 == 1)
            {
                top = top2;
            }
            else
            {
                top = top1;
            }

            left = i * fwidth;

            g.drawstring(code.substring(i, 1), f, b, left, top);
        }

        //画一个边框 边框颜色为color.gainsboro
        g.drawrectangle(new pen(color.gainsboro, 0), 0, 0, image.width - 1, image.height - 1);
        g.dispose();

        //产生波形（add by 51aspx.com）
        image = twistimage(image, true, 8, 4);

        return image;
    }

    /// <summary>
    /// 生成随机字符码
    /// </summary>
    /// <param name="codelen">字符串长度</param>
    /// <param name="zhcharscount">中文字符数</param>
    /// <returns></returns>
    public string createverifycode(int codelen, int zhcharscount)
    {
        char[] chs = new char[codelen];

        int index;
        for (int i = 0; i < zhcharscount; i++)
        {
            index = rnd.next(0, codelen);
            if (chs[index] == '\0')
                chs[index] = createzhchar();
            else
                --i;
        }
        for (int i = 0; i < codelen; i++)
        {
            if (chs[i] == '\0')
                chs[i] = createenornumchar();
        }

        return new string(chs, 0, chs.length);
    }

    /// <summary>
    /// 生成默认长度5的随机字符码
    /// </summary>
    /// <returns></returns>
    public string createverifycode()
    {
        return createverifycode(length, 0);
    }

    /// <summary>
    /// 生成英文或数字字符
    /// </summary>
    /// <returns></returns>
    protected char createenornumchar()
    {
        return englishornumchars[rnd.next(0, englishornumchars.length)];
    }

    /// <summary>
    /// 生成汉字字符
    /// </summary>
    /// <returns></returns>
    protected char createzhchar()
    {
        //若提供了汉字集，查询汉字集选取汉字
        if (chinesechars.length > 0)
        {
            return chinesechars[rnd.next(0, chinesechars.length)];
        }
        //若没有提供汉字集，则根据《gb2312简体中文编码表》编码规则构造汉字
        else
        {
            byte[] bytes = new byte[2];

            //第一个字节值在0xb0, 0xf7之间
            bytes[0] = (byte)rnd.next(0xb0, 0xf8);
            //第二个字节值在0xa1, 0xfe之间
            bytes[1] = (byte)rnd.next(0xa1, 0xff);

            //根据汉字编码的字节数组解码出中文汉字
            string str1 = encoding.getencoding("gb2312").getstring(bytes);

            return str1[0];
        }
    }

}