////////////////////////////////////////////////////////////////////////////////////////////////////////////////
/// <summary>
/// Method: Change Format of Drawing text.
/// </summary>
/// <param name="format"> The format.</param>
/// <returns>
/// The old format.
/// </returns>
////////////////////////////////////////////////////////////////////////////////////////////////////////////////
public DrawFormat ChangeFormat(DrawFormat format)
{
var old = _format;
_format = format;
return(old);
}
private static ImageFormat GetImageFormat(DrawFormat imageFormat)
{
switch (imageFormat)
{
case DrawFormat.Bmp: return(ImageFormat.Bmp);
case DrawFormat.Emf: return(ImageFormat.Emf);
case DrawFormat.Exif: return(ImageFormat.Exif);
case DrawFormat.Gif: return(ImageFormat.Gif);
case DrawFormat.Icon: return(ImageFormat.Icon);
case DrawFormat.Jpeg: return(ImageFormat.Jpeg);
case DrawFormat.MemoryBmp: return(ImageFormat.MemoryBmp);
case DrawFormat.Tiff: return(ImageFormat.Tiff);
case DrawFormat.Wmf: return(ImageFormat.Wmf);
default: return(ImageFormat.Png);
}
}
public DrawSettings(DrawFormat drawFormat, Font font, Color color, IColorizer colorizer)
{
DrawFormat = drawFormat;
Font = font;
Color = color;
Colorizer = colorizer;
}
////////////////////////////////////////////////////////////////////////////////////////////////////////////////
/// <summary>
/// Method: Start Drawing, sets the background color and clears the clip region, set tab and basic draw format.
/// </summary>
/// <param name="graphics"> The graphics.</param>
/// <param name="background"> The background.</param>
/// <param name="tabSize"> The tab Size.</param>
/// <param name="font"> The font.</param>
/// <param name="format"> [optional=(DrawFormat.DT_NOPREFIX | DrawFormat.DT_NOCLIP)] The format.</param>
////////////////////////////////////////////////////////////////////////////////////////////////////////////////
public void StartDrawing(Graphics graphics, Color background, int tabSize, Font font, DrawFormat format = (DrawFormat.DT_NOPREFIX | DrawFormat.DT_NOCLIP))
{
graphics.Clear(background);
_dc = graphics.GetHdc();
_textParams = new DRAWTEXTPARAMS(tabSize);
_format = format;
SetBkMode(_dc, BkMode.TRANSPARENT);
SelectFont(font);
}
/// <summary>
/// 生成验证码图片
/// </summary>
/// <param name="chkCode">验证码内容</param>
/// <param name="imageFormat">图片格式（默认为Png）</param>
/// <param name="codeWidth">图片宽度</param>
/// <param name="codeHeight">图片高度</param>
/// <param name="fontSize">字体大小</param>
/// <returns>验证码图片字节流</returns>
public static byte[] Generate(string chkCode, DrawFormat imageFormat = DrawFormat.Png, int codeWidth = 80, int codeHeight = 30, int fontSize = 16)
{
bmp = new Bitmap(codeWidth, codeHeight);
Random rnd = new Random();
//颜色列表，用于验证码、噪线、噪点
//颜色列表，用于验证码、噪线、噪点
//字体列表，用于验证码
//字体列表，用于验证码
//验证码的字符集，去掉了一些容易混淆的字符
//验证码的字符集，去掉了一些容易混淆的字符
//写入Session、验证码加密
//WebHelper.WriteSession("session_verifycode", Md5Helper.MD5(chkCode.ToLower(), 16));
//创建画布
Graphics g = Graphics.FromImage(bmp);
g.Clear(Color.White);
//画噪线
for (int i = 0; i < 5; i++)
{
int x1 = rnd.Next(codeWidth);
int y1 = rnd.Next(codeHeight);
int x2 = rnd.Next(codeWidth);
int y2 = rnd.Next(codeHeight);
Color clr = color[rnd.Next(color.Length)];
g.DrawLine(new Pen(clr), x1, y1, x2, y2);
}
//画验证码字符串
for (int i = 0; i < chkCode.Length; i++)
{
string fnt = fonts[rnd.Next(fonts.Length)];
Font ft = new Font(fnt, fontSize, FontStyle.Bold);
Color clr = color[rnd.Next(color.Length)];
g.DrawString(chkCode[i].ToString(), ft, new SolidBrush(clr), (float)i * 18, (float)0);
}
MemoryStream ms = new MemoryStream();
try
{
bmp.Save(ms, GetImageFormat(imageFormat));
return(ms.ToArray());
}
catch (Exception)
{
return(null);
}
finally
{
g.Dispose();
bmp.Dispose();
}
}
/// <summary>
/// Performs application-defined tasks associated with freeing, releasing, or resetting unmanaged resources.
/// </summary>
public void Dispose()
{
DrawFormat?.Dispose();
StringFormat?.Dispose();
Font?.Dispose();
}
