图片加水印图片验证码

图片加水印

1 获取这张图片

System.Drawing.Image img = System.Drawing.Image.FromStream(FileUpload1.FileContent);

2 给图片加水印

Graphics g = Graphics.FromImage(img);

string s = "WWW.ITNBA.COM"; s 给图片加的水印文字

Font f = new Font("微软雅黑", 30);

Brush b = new SolidBrush(Color.Red);

PointF pf = new PointF(50, 50);

g.DrawString(s, f, b, pf);

3 保存这张图

string path = "Uploads/" + DateTime.Now.ToString("yyyyMMddhhmmssms") + FileUpload1.FileName;

img.Save(Server.MapPath(path));

Image1.ImageUrl = path;

网页保存这张图回事aspx格式将后缀改成png格式即可查看图片

小知识：图片转换成txt格式会出现乱码在乱码下方添加文字再转换成jpg个是不会影响图片

图片格式的验证码

 List<Color> clist = new List<Color>();
        clist.Add(Color.Red);
        clist.Add(Color.Firebrick);
        clist.Add(Color.LawnGreen);
        clist.Add(Color.Goldenrod);
        clist.Add(Color.Cyan);
        clist.Add(Color.DarkSlateBlue);
        clist.Add(Color.Indigo);
        Random r = new Random();
        string s = "";
        string all = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmeopqrstuvwxyz0123456789";
        for (int i = 0; i < 4; i++)
        {
            s += all.Substring(r.Next(0, all.Length), 1);
        }

        Session["YZM"] = s;

        Bitmap img = new Bitmap(120, 60);

        Graphics g2 = Graphics.FromImage(img);
        Brush b2 = new SolidBrush(clist[r.Next(0, clist.Count)]);
        g2.FillRectangle(b2, 0, 0, 120, 60);

        Graphics g = Graphics.FromImage(img);
        Font f = new Font("微软雅黑", 30);
        Brush b = new SolidBrush(Color.Red);

        g.DrawString(s, f, b, new PointF(0, 0));


        for (int i = 0; i < 8; i++)
        {
            Graphics g3 = Graphics.FromImage(img);
            Pen p3 = new Pen(new SolidBrush(clist[r.Next(0, clist.Count)]), r.Next(2, 5));
            g3.DrawLine(p3, new Point(r.Next(0, 120), r.Next(0, 60)), new Point(r.Next(0, 120), r.Next(0, 60)));
        }


        img.Save(Response.OutputStream, System.Drawing.Imaging.ImageFormat.Png);

图片后台

前台验验证验证码
var a = 0;
    document.getElementById("yzm1").onclick = function () {
        this.src = "yzm.aspx?a=" + a;
        a++;
    }

点击图片切换验证码方正验证码图片重复打开的验证码图片传个值这个值用不到

就可以实现图片无限刷新

toUpperCase 实现验证码大小写转换

图片加水印 图片验证码

图片加水印图片验证码