Home  >  Article  >  php教程  >  Web front-end development watermark, picture verification code

Web front-end development watermark, picture verification code

高洛峰
高洛峰Original
2016-12-05 10:00:261275browse

1. Watermark

1. Canvas

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

2. Create a drawing object and tell it which picture to draw on

Graphics g = Graphics.FromImage(img);

3. Drawing content

string s = <a href="http://www.php.cn">www.php.cn</a>;

4 . Drawing font

Font f = new Font("黑体",130);

5. Drawing brush

Brush b = new SolidBrush(Color.Red);

6. Start drawing

g.DrawString(s, f, b, 5, 5);

2. Picture verification code

Bitmap bit = new Bitmap(90, 40);//画布大小
    Graphics g = Graphics.FromImage(bit);//创建绘制对象,告诉它往哪张图片上绘制
    Random r = new Random();
    string s = "";
    Color color1 = Color.FromArgb(r.Next(155, 255), r.Next(155, 255), r.Next(155, 255));
    g.FillRectangle(new SolidBrush(color1), 0, 0, 90, 40);//画布颜色随机
    for (int i = 0; i < 10; i++)//随机画干扰线
    {
      Color color3 = Color.FromArgb(r.Next(170, 255), r.Next(190, 255), r.Next(170, 255));
      Pen pp = new Pen(new SolidBrush(color3), r.Next(0, 5));
      g.DrawLine(pp, r.Next(0, 90), r.Next(0, 40), r.Next(0, 90), r.Next(0, 40));
    }
    string yan = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890";//设置随机的验证码,从里面抽取
    int wei = 0;
    for (int i = 0; i < 4; i++)//取四位验证码,颜色随机
    {
      string m = yan.Substring(r.Next(0, yan.Length), 1);
      s += m;
      Color color2 = Color.FromArgb(r.Next(0, 155), r.Next(0, 155), r.Next(0, 155));
      int w = r.Next(20, 25);
      Font f = new Font("黑体", w);
      SolidBrush b = new SolidBrush(color2);
      g.DrawString(m, f, b, wei, r.Next(0, 10));
      wei += w;
    }
    Session["YZM"] = s;//把验证码保存到session中
    for (int i = 0; i < 251; i++)
    {
      Color color3 = Color.FromArgb(r.Next(0, 255), r.Next(0, 255), r.Next(0, 255));
      Pen pp = new Pen(new SolidBrush(color3), r.Next(0, 5));
      int a = r.Next(0, 90);
      int b = r.Next(0, 40);
      g.DrawLine(pp, a, b, (a + 1), (b + 1));
    }
    bit.Save(Response.OutputStream, System.Drawing.Imaging.ImageFormat.Jpeg);
    Response.End();

Verification code:

<asp:TextBox ID="TextBox3" runat="server"></asp:TextBox>
    <asp:Image ID="Image1" runat="server" ImageUrl="Default2.aspx" />//这里图片路径不是一张图片的话会默认打开

The above is the watermark and image verification code for Web front-end development shared by the editor. I hope it will be helpful to everyone


Statement:
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn