You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
106 lines
3.1 KiB
C#
106 lines
3.1 KiB
C#
using System;
|
|
using System.Collections.Generic;
|
|
using System.Drawing;
|
|
using System.Drawing.Imaging;
|
|
using System.IO;
|
|
using System.Text;
|
|
using System.Threading.Tasks;
|
|
|
|
namespace Admin.Core.Common
|
|
{
|
|
public class Captcha : ICaptcha
|
|
{
|
|
private const string Letters = "1,2,3,4,5,6,7,8,9,A,B,C,D,E,F,G,H,J,K,L,M,N,P,Q,R,S,T,U,V,W,X,Y,Z";
|
|
|
|
public Task<CaptchaResult> GenerateCaptchaImage(string captchaCode, int width = 0, int height = 30)
|
|
{
|
|
//验证码颜色集合
|
|
Color[] c = { Color.Black, Color.Red, Color.DarkBlue, Color.Green, Color.Orange, Color.Brown, Color.DarkCyan, Color.Purple };
|
|
|
|
//验证码字体集合
|
|
string[] fonts = { "Verdana", "Microsoft Sans Serif", "Comic Sans MS", "Arial" };
|
|
|
|
//定义图像的大小,生成图像的实例
|
|
var image = new Bitmap(width == 0 ? captchaCode.Length * 25 : width, height);
|
|
|
|
var g = Graphics.FromImage(image);
|
|
|
|
//背景设为白色
|
|
g.Clear(Color.White);
|
|
|
|
var random = new Random();
|
|
|
|
for (var i = 0; i < 100; i++)
|
|
{
|
|
var x = random.Next(image.Width);
|
|
var y = random.Next(image.Height);
|
|
g.DrawRectangle(new Pen(Color.LightGray, 0), x, y, 1, 1);
|
|
}
|
|
|
|
//验证码绘制在g中
|
|
for (var i = 0; i < captchaCode.Length; i++)
|
|
{
|
|
//随机颜色索引值
|
|
var cindex = random.Next(c.Length);
|
|
|
|
//随机字体索引值
|
|
var findex = random.Next(fonts.Length);
|
|
|
|
//字体
|
|
var f = new Font(fonts[findex], 15, FontStyle.Bold);
|
|
|
|
//颜色
|
|
Brush b = new SolidBrush(c[cindex]);
|
|
|
|
var ii = 4;
|
|
if ((i + 1) % 2 == 0)
|
|
ii = 2;
|
|
|
|
//绘制一个验证字符
|
|
g.DrawString(captchaCode.Substring(i, 1), f, b, 17 + (i * 17), ii);
|
|
}
|
|
|
|
var ms = new MemoryStream();
|
|
image.Save(ms, ImageFormat.Png);
|
|
|
|
g.Dispose();
|
|
image.Dispose();
|
|
|
|
return Task.FromResult(new CaptchaResult
|
|
{
|
|
CaptchaCode = captchaCode,
|
|
CaptchaMemoryStream = ms,
|
|
Timestamp = DateTime.Now
|
|
});
|
|
}
|
|
|
|
public Task<string> GenerateRandomCaptcha(int codeLength = 4)
|
|
{
|
|
var array = Letters.Split(new[] { ',' });
|
|
|
|
var random = new Random();
|
|
|
|
var temp = -1;
|
|
|
|
var captcheCode = string.Empty;
|
|
|
|
for (int i = 0; i < codeLength; i++)
|
|
{
|
|
if (temp != -1)
|
|
random = new Random(i * temp * unchecked((int)DateTime.Now.Ticks));
|
|
|
|
var index = random.Next(array.Length);
|
|
|
|
if (temp != -1 && temp == index)
|
|
return GenerateRandomCaptcha(codeLength);
|
|
|
|
temp = index;
|
|
|
|
captcheCode += array[index];
|
|
}
|
|
|
|
return Task.FromResult(captcheCode);
|
|
}
|
|
}
|
|
}
|