/// <summary>
/// 构造函数
/// </summary>
public VerificationCodeHelper(VerificationCodeRule rule)
{
HttpContext.Current.Response.Expires = 0;
HttpContext.Current.Response.Buffer = true;
HttpContext.Current.Response.ExpiresAbsolute = DateTime.Now.AddSeconds(-1);
HttpContext.Current.Response.AddHeader("pragma", "no-cache");
HttpContext.Current.Response.CacheControl = "no-cache";
CreateImage(rule);
}
/// <summary>
/// 绘制验证码
/// </summary>
public void CreateImage(VerificationCodeRule rule)
{
_text = RandomHelper.Number(rule.LetterCount);
int intImageWidth = _text.Length * rule.LetterWidth;
Bitmap dstImage = new Bitmap(intImageWidth, rule.LetterHeight);
Graphics g = Graphics.FromImage(dstImage);
g.Clear(Color.White);
for (int i = 0; i < 2; i++)
{
int x1 = Next(dstImage.Width - 1);
int x2 = Next(dstImage.Width - 1);
int y1 = Next(dstImage.Height - 1);
int y2 = Next(dstImage.Height - 1);
g.DrawLine(new Pen(Color.Silver), x1, y1, x2, y2);
}
int px = -12;
for (int intIndex = 0; intIndex < this._text.Length; intIndex++)
{
px += Next(12, 16);
var py = Next(-2, 2);
string strChar = this._text.Substring(intIndex, 1);
strChar = Next(1) == 1 ? strChar.ToLower() : strChar.ToUpper();
Brush newBrush = new SolidBrush(GetRandomColor());
Point thePos = new Point(px, py);
g.DrawString(strChar, _fonts[Next(_fonts.Length - 1)], newBrush, thePos);
}
for (int i = 0; i < 10; i++)
{
int x = Next(dstImage.Width - 1);
int y = Next(dstImage.Height - 1);
dstImage.SetPixel(x, y, Color.FromArgb(Next(0, 255), Next(0, 255), Next(0, 255)));
}
dstImage = TwistImage(dstImage, true, Next(1, 3), Next(4, 6));
g.DrawRectangle(new Pen(Color.LightGray, 1), 0, 0, intImageWidth - 1, rule.LetterHeight - 1);
_image = dstImage;
}