一、水印
1.画布
2.创建绘制对象，告诉它往哪张图片上绘制
3.绘制的内容
;
4.绘制的字体
5.绘制的画刷
6.开始绘制
二、图片验证码
图片上绘制
Random r = new Random();
string s = "";
Color color1 = Color.FromArgb(r.Next(155,255),r.Next(155,255));
g.FillRectangle(new SolidBrush(color1),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,r.Next(190,r.Next(170,255));
Pen pp = new Pen(new SolidBrush(color3),r.Next(0,5));
g.DrawLine(pp,90),40),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),155));
int w = r.Next(20,25);
Font f = new Font("黑体",w);
SolidBrush b = new SolidBrush(color2);
g.DrawString(m,wei,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(0,5));
int a = r.Next(0,90);
int b = r.Next(0,40);
g.DrawLine(pp,a,(a + 1),(b + 1));
}
bit.Save(Response.OutputStream,System.Drawing.Imaging.ImageFormat.Jpeg);
Response.End();
验证码：
以上所述是小编给大家分享的Web前端开发之水印、图片验证码，希望对大家有所帮助，如果大家有任何疑问欢迎给我留言，小编会及时回复大家的，在此也非常感谢大家对编程之家网站的支持！
原文链接：https://www.f2er.com/js/44138.html