後臺生產驗證碼code和byte[]圖片

引用命名空間

using System.Drawing;
using System.Drawing.Drawing2D;
using System.Drawing.Imaging;
using System.IO;

生成方法

/// <summary>生成驗證碼
/// </summary>
/// <returns></returns>
public string GetCheckCode()
{
int number;
char code;
string checkCode = String.Empty;

System.Random random = new Random();
do
{
number = random.Next();
if (number % 2 == 0)
code = (char)('0' + (char)(number % 10));
else
code = (char)('A' + (char)(number % 26));
if (code == 'o' || code == 'O') continue;
checkCode += code.ToString();
} while (checkCode.Length < 4);
//code儲存.在session
KMHC.Infrastructure.SessionHelper.SetSession("checkCode", checkCode.ToUpper());

byte[] bytes = CreateValidateGraphic(checkCode.ToLower());
var response = new BaseResponse<string>();
var src = "data:image/jpeg;base64," + Convert.ToBase64String(bytes);//Base64轉換 HTML標簽img 直接顯示 <img src="" />
return src;
}

/// <summary>
/// 創建驗證碼的圖片
/// </summary>
/// <param name="containsPage"></param>
/// <param name="validateNum"></param>
public static byte[] CreateValidateGraphic(string checkCode)
{
Bitmap image = new Bitmap((int)Math.Ceiling(checkCode.Length * 13.5), 22);
Graphics g = Graphics.FromImage(image);
try
{
//生成隨機生成器
Random random = new Random();
//清空圖片背景色
g.Clear(Color.White);
//畫圖片的干擾線
for (int i = 0; i < 25; i++)
{
int x1 = random.Next(image.Width); int x2 = random.Next(image.Width);
int y1 = random.Next(image.Height);
int y2 = random.Next(image.Height);
g.DrawLine(new Pen(Color.Silver), x1, y1, x2, y2);
}
Font font = new Font("Arial", 12, (FontStyle.Bold | FontStyle.Italic));
LinearGradientBrush brush = new LinearGradientBrush(new Rectangle(0, 0, image.Width, image.Height),
Color.Blue, Color.DarkRed, 1.2f, true); g.DrawString(checkCode, font, brush, 3, 2);
//畫圖片的前景干擾點
for (int i = 0; i < 100; i++)
{
int x = random.Next(image.Width); int y = random.Next(image.Height);
image.SetPixel(x, y, Color.FromArgb(random.Next()));
}
//畫圖片的邊框線
g.DrawRectangle(new Pen(Color.Silver), 0, 0, image.Width - 1, image.Height - 1);
//保存圖片數據
MemoryStream stream = new MemoryStream();
image.Save(stream, ImageFormat.Jpeg);
//輸出圖片

return stream.ToArray();
}
finally
{
g.Dispose();
image.Dispose();
}
}