/// <summary>
/// 获取一个验证码字串及PNG图片数据
/// </summary>
/// <param name="length">验证码长度(4比较合适)</param>
/// <param name="checkcode">随机生成的验证码字符串</param>
/// <returns></returns>
public static byte[] GetImage(int length, out string checkcode)
{
checkcode = RandomText.String(length);
var random = new Random();
//注意，字体应该是所在操作系统中存在的字体 "Comic Sans MS"
var font = new Font("Comic Sans MS", 20, FontStyle.Bold | FontStyle.Italic, GraphicsUnit.Pixel);
var stringFormat = new StringFormat
{
Alignment = StringAlignment.Center,
LineAlignment = StringAlignment.Center
};
using (var bitmap = new Bitmap((int)Math.Ceiling((double)(length * 18)), 27, PixelFormat.Format24bppRgb))
{
using (var graphics = Graphics.FromImage(bitmap))
{
graphics.Clear(Color.White);
graphics.SmoothingMode = SmoothingMode.AntiAlias;
graphics.TextRenderingHint = TextRenderingHint.AntiAlias;
//画图片的背景噪音线
for (int i = 0; i < 5; i++)
{
int x1 = random.Next(bitmap.Width);
int x2 = random.Next(bitmap.Width);
int y1 = random.Next(bitmap.Height);
int y2 = random.Next(bitmap.Height);
graphics.DrawLine(new Pen(Color.Silver), x1, y1, x2, y2);
}
graphics.DrawString(checkcode, font, Brushes.Black, new RectangleF(0f, 0f, (float)bitmap.Width, (float)bitmap.Height), stringFormat);
//画图片的前景噪音点
for (int i = 0; i < 20; i++)
{
int x = random.Next(bitmap.Width);
int y = random.Next(bitmap.Height);
bitmap.SetPixel(x, y, Color.FromArgb(random.Next()));
}
}
using (var bitmap2 = WaveDistortion(bitmap))
{
using (var ms = new System.IO.MemoryStream())
{
bitmap2.Save(ms, ImageFormat.Png);
//bitmap2.Save("img.jpg");
return(ms.ToArray());
}
}
}
}
