using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Drawing.Drawing2D;

namespace 验证码
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }
        public string txt = "";
        private void Form1_Load(object sender, EventArgs e)
        {
            CreateImage();
        }
        private void CreateImage()
        {
            string[] r = new String[62]{ "0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "a", "b", "c", "d", "e", "f","g","h","i","j","k","l","m","n","o","p","q","r","s","t","u","v","w","x","y","z",
            "A","B","C","D","E","F","G","H","I","J","K","L","M","N","O","P","Q","R","S","T","U","V","W","X","Y","Z"}; 
            Random x = new Random();
            string str1 = r[x.Next(0, 62)], str2 =r[x.Next(0, 62)], str3 =r[x.Next(0, 62)], str4 =r[x.Next(0, 62)];
            txt = str1 + str2 + str3 + str4;
            if (txt == null || txt == String.Empty)
            {
                return;
            }
            Bitmap image = new Bitmap((int)Math.Ceiling((txt.Length*15.0)), 20);
            Graphics g = Graphics.FromImage(image);
            try
            {
                //生成随机生成器
                Random random = new Random();
                //清空图片背景色以白色填充
                g.Clear(Color.White);
                //画图片的背景噪音线
                for (int i = 0; i < 3; i++)
                {
                    Point tem_Point_1 = new Point(random.Next(image.Width), random.Next(image.Height));
                    Point tem_Point_2 = new Point(random.Next(image.Width), random.Next(image.Height));
                    g.DrawLine(new Pen(Color.Black), tem_Point_1, tem_Point_2);
                }
                Font font = new Font("Arial", 12, (FontStyle.Bold));
                LinearGradientBrush brush = new LinearGradientBrush(new Rectangle(0, 0, image.Width, image.Height), Color.Pink , Color.Red, 1.2f, true);
                g.DrawString(txt, font, brush, 2, 2);
                //画图片的前景噪音点
                for (int i = 0; i < 100; i++)
                {
                    Point tem_point = new Point(random.Next(image.Width), random.Next(image.Height));
                    image.SetPixel(tem_point.X, tem_point.Y, Color.FromArgb(random.Next()));
                }
                //画图片的边框线
                g.DrawRectangle(new Pen(Color.Silver), 0, 0, image.Width - 1, image.Height - 1);
                pictureBox1.Image = image;
            }
            catch (Exception e)
            {
                MessageBox.Show(e.Message);
            }
        }

        private void button2_Click(object sender, EventArgs e)
        {
            CreateImage();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            if (textBox1.Text.Trim() =="")