this.OnPaint();
}
}
/**//**//**//// <summary>
/// 设置页面不被缓存
/// </summary>
private void SetPageNoCache()
...{
Response.Buffer = true;
Response.ExpiresAbsolute = System.DateTime.Now.AddSeconds(-1);
Response.Expires = 0;
Response.CacheControl = "no-cache";
Response.AppendHeader("Pragma","No-Cache");
}
/**//**//**//// <summary>
/// 取得一个 4 位的随机码
/// </summary>
/// <returns></returns>
private string GetRandomCode()
...{
return Guid.NewGuid().ToString().Substring(0, 4);
}
/**//**//**//// <summary>
/// 随机取一个字体
/// </summary>
/// <returns></returns>
private Font GetFont()
...{
int fontIndex = _random.Next(0, FontItems.Length);
FontStyle fontStyle = GetFontStyle(_random.Next(0, 2));
return new Font(FontItems[fontIndex], 12, fontStyle);
}
/**//**//**//// <summary>
/// 取一个字体的样式
/// </summary>
/// <param name="index"></param>
/// <returns></returns>
private FontStyle GetFontStyle(int index)
...{
switch (index)
...{
case 0:
return FontStyle.Bold;
case 1:
return FontStyle.Italic;
default:
return FontStyle.Regular;
}
}
/**//**//**//// <summary>
/// 随机取一个笔刷
/// </summary>
/// <returns></returns>
private Brush GetBrush()
...{
int brushIndex = _random.Next(0, BrushItems.Length);
_brushNameIndex = brushIndex;
return BrushItems[brushIndex];
}
/**//**//**//// <summary>
/// 绘画事件
/// </summary>
private void OnPaint()
...{
Bitmap objBitmap = null;
Graphics g = null;
try
...{
objBitmap = new Bitmap(Width, Height);
g = Graphics.FromImage(objBitmap);
Paint_Background(g);
Paint_Text(g);
Paint_TextStain(objBitmap);
Paint_Border(g);
objBitmap.Save(Response.OutputStream, ImageFormat.Gif);
Response.ContentType = "image/gif";
}
catch ...{}
finally
...{
if (null != objBitmap)
objBitmap.Dispose();
if (null != g)
g.Dispose();
}
}
/**//**//**//// <summary>
/// 绘画背景颜色
/// </summary>
/// <param name="g"></param>
private void Paint_Background(Graphics g)
...{
g.Clear(BackColor);
}
/**//**//**//// <summary>
/// 绘画边框
/// </summary>
/// <param name="g"></param>
private void Paint_Border(Graphics g)
...{
g.DrawRectangle(BorderColor, 0, 0, Width - 1, Height - 1);
}
/**//**//**//// <summary>
/// 绘画文字
/// </summary>
/// <param name="g"></param>
private void Paint_Text(Graphics g)
...{
g.DrawString(_code, GetFont(), GetBrush(), 3, 1);
}
/**//**//**//// <summary>
/// 绘画文字噪音点
/// </summary>
