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[ASP.net教程]C# 生成验证码图片时消除锯齿

引言

      基于生成图片实现了一个手机号转图片的需求。 内容也很简单,直接用手机号生成一个png图片。就是为了背景透明以便其他地方调用。 有无锯齿主要依靠一句代码:g.TextRenderingHint= TextRenderingHint.AntiAlias;

 

生成图片 

1、有锯齿

2、无锯齿

 

生成方法

string color = "#ff6633";    System.Drawing.Bitmap image = new System.Drawing.Bitmap(170, 35);    Graphics g = Graphics.FromImage(image);        try    {      g.TextRenderingHint= TextRenderingHint.AntiAlias; //消除锯齿            //生成随机生成器      Random random = new Random();      //清空图片背景色      //g.Clear(Color.Transparent);      //画图片的背景噪音线      /*for (int i = 0; i < 2; 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.Black), x1, y1, x2, y2);      }      */      System.Drawing.ColorConverter colConvert = new System.Drawing.ColorConverter();      Color fontColor =(System.Drawing.Color)colConvert.ConvertFromString(color);            Font font = new System.Drawing.Font("Arial", 18, System.Drawing.FontStyle.Bold);      LinearGradientBrush brush = new LinearGradientBrush(new Rectangle(0, 0, image.Width, image.Height), fontColor, fontColor,LinearGradientMode.Horizontal);      g.DrawString(phone, font, brush, 2, 2);            //画图片的前景噪音点      //for (int i = 0; i < 50; i++)      //{      //  int x = random.Next(image.Width);      //  int y = random.Next(image.Height);      //  image.SetPixel(x, y, Color.FromArgb(random.Next()));      //}      //画图片的边框线      //g.DrawRectangle(new Pen(Color.White), 0, 0, image.Width - 1, image.Height - 1);      System.IO.MemoryStream ms = new System.IO.MemoryStream();      Color backColor = image.GetPixel(1, 1);      image.MakeTransparent(backColor);      image.Save(ms, System.Drawing.Imaging.ImageFormat.Png);      context.Response.ClearContent();      context.Response.ContentType = "image/x-png";      context.Response.BinaryWrite(ms.ToArray());    }    finally    {      g.Dispose();      image.Dispose();    }

 

参考资料

http://www.blue1000.com/bkhtml/c17/2013-03/71115.htm