asp.net 可以自己生成图像吗?

Question

我想自己建个jpg的图像,上面放些文字和背景,请问c#能做到吗?
谢谢

Answer 1

生成验证码的,就是自己生成的,参考:
protected void Page_Load(object sender, EventArgs e)
    {
        Response.Expires = 0;
        Response.CacheControl = "no-cache";
        Session["VNum"] = GenerateCheckCode();
        this.CreateCheckCodeImage(GenerateCheckCode());
    }
    private string GenerateCheckCode()
    {
        int number;
        char code;
        string checkCode = String.Empty;        System.Random random = new Random();        for (int i = 0; i < 4; i++)
        {
            number = random.Next();            if(number % 2 == 0)
                code = (char)('0' + (char)(number % 10));
            else
                code = (char)('A' + (char)(number % 26));            checkCode += code.ToString();
        }        Response.Cookies.Add(new HttpCookie("CheckCode", checkCode));        return checkCode;
    }    private void CreateCheckCodeImage(string checkCode)
    {
        if (checkCode == null || checkCode.Trim() == String.Empty)
            return;        System.Drawing.Bitmap image = new System.Drawing.Bitmap((int)Math.Ceiling((checkCode.Length * 16.0)), 25);  //15.0是每个字符的宽度,25是高度
        Graphics g = Graphics.FromImage(image);        try
        {
            //生成随机生成器
            Random random = new Random();            //清空图片背景色
            g.Clear(Color.White);            //画图片的背景噪音线
            for (int i = 0; i < 25; 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.Silver), x1, y1, x2, y2);
            }            //15是字号大小
            Font font = new System.Drawing.Font("Arial", 15, (System.Drawing.FontStyle.Bold | System.Drawing.FontStyle.Italic));
            System.Drawing.Drawing2D.LinearGradientBrush brush = new System.Drawing.Drawing2D.LinearGradientBrush(new Rectangle(0, 0, image.Width, image.Height), Color.Blue, Color.DarkRed, 1.2f, true);
            g.DrawString(checkCode, font, brush, 2, 2);            //画图片的前景噪音点
            for (int i = 0; i < 100; 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.Silver), 0, 0, image.Width - 1, image.Height - 1);            System.IO.MemoryStream ms = new System.IO.MemoryStream();
            image.Save(ms, System.Drawing.Imaging.ImageFormat.Gif);
            Response.ClearContent();
            Response.ContentType = "image/Gif";
            Response.BinaryWrite(ms.ToArray());
        }
        finally
        {
            g.Dispose();
            image.Dispose();
        }
    }

Answer 2

还要加上这个命名空间:
using System.Drawing;

Answer 3

应该是可以在画布上做到这些的, 我没有做过, 大概提供一个思路参考一下吧
读取一个图片得到Image对象,调用Graphics.FromImage方法, 得到Graphics;或者是用Graphics的DrawImage把image画到Graphics上. 然后调用Graphics.DrawString方法在Graphics上写文字.
最后然后保存, 保存怎么做我还没想到

Answer 4

参看
http://blog.csdn.net/knight94/archive/2006/03/24/637727.aspx

Answer 5

看看这个,生成验证码的
 Bitmap newBitmap = new Bitmap(86, 26, System.Drawing.Imaging.PixelFormat.Format32bppArgb);
        Graphics g = Graphics.FromImage(newBitmap);
        Random r = new Random();
        g.Clear(Color.White);
        System.Drawing.Drawing2D.LinearGradientBrush brush = new System.Drawing.Drawing2D.LinearGradientBrush(new Rectangle(0, 0, 86, 26), Color.Red, Color.Blue, 1.2f, true);
        
        for (int i = 0; i < 25; i++)
        {
            int x1 = r.Next(newBitmap.Width);
            int x2 = r.Next(newBitmap.Width);
            int y1 = r.Next(newBitmap.Height);
            int y2 = r.Next(newBitmap.Height);
            g.DrawLine(new Pen(Color.Silver), x1, y1, x2, y2);
        }
        for (int i = 0; i < 100; i++)
        {
            int x = r.Next(newBitmap.Width);
            int y = r.Next(newBitmap.Height);
            newBitmap.SetPixel(x, y, Color.FromArgb(r.Next()));
        }
        string value = GenerateRandom(4);
        Font font = new Font("黑体", 14, System.Drawing.FontStyle.Bold);
        g.DrawString(value, font, brush,2, 2);
        g.DrawRectangle(new Pen(Color.Silver),0,0,85,25);
        //g.FillRectangle(new SolidBrush(Color.Green), 0, 12, 80, 1);
        System.IO.MemoryStream ms = new System.IO.MemoryStream();
        newBitmap.Save(ms, System.Drawing.Imaging.ImageFormat.Gif);
        Response.ClearContent();
        Response.ContentType = "image/gif";
        Response.BinaryWrite(ms.ToArray());
    }
    private static char[] constant =
        {
            '0','1','2','3','4','5','6','7','8','9',
            'a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z','
        };
    public static string GenerateRandom(int Length)
    {
        System.Text.StringBuilder newRandom = new System.Text.StringBuilder(47);
        Random rd = new Random();
        for (int i = 0; i < Length; i++)
        {
            newRandom.Append(constant[rd.Next(47)]);
        }
        return newRandom.ToString();
    }

Answer 6

http://www.webjx.com/htmldata/2006-01-21/1137824356.html

Answer 7

WeekZero(星期零)的不错，可以参考