webform（十）——圖片水印和圖片驗證碼，webform水印

webform（十）——圖片水印和圖片驗證碼，webform水印

兩者都需要引入命名空間：using System.Drawing;

一、圖片水印

前台Photoshuiyin.aspx代碼：

<div>
    <asp:FileUpload ID="FileUpload1" runat="server" />
        <asp:Button ID="Button1" runat="server" Text="上傳" /><br />
        <asp:Image ID="Image1" runat="server" />
    </div>

後台Photoshuiyin.aspx.cs代碼：

protected void Page_Load(object sender, EventArgs e)
    {
        Button1.Click += Button1_Click;
    }

    void Button1_Click(object sender, EventArgs e)
    {
        //1、制作畫布
        System.Drawing.Image img = System.Drawing.Image.FromStream(FileUpload1.FileContent);

        Graphics g = Graphics.FromImage(img);
        //水印樣式：畫什麼東西
        string a = "http://www.itnba.com";
        //字體、大小
        Font f = new Font("黑體", 30);
        //顏色
        Brush b = new SolidBrush(Color.Red);
        //0,0——開始畫水印的位置
        g.DrawString(a, f, b, 0, 0);
        //保存路徑
        string path = "images/" + FileUpload1.FileName;
        img.Save(Server.MapPath(path));
        //在image控件中展示
        Image1.ImageUrl = path;

    }

效果展示：

二、圖片驗證碼

前台Photoyanzhengma.aspx代碼：

<form id="form1" runat="server">
    <div>
            用戶名：<asp:TextBox ID="TextBox1" runat="server"></asp:TextBox>
            <br />
            密碼：<asp:TextBox ID="TextBox2" runat="server"></asp:TextBox>
            <br />
            驗證碼：<asp:TextBox ID="TextBox3" runat="server"></asp:TextBox>
            <asp:Image ID="Image1" runat="server" ImageUrl="YZM.aspx" />
            <asp:Label ID="Label1" runat="server" Text="Label"></asp:Label>
            <br />
            <asp:Button ID="Button1" runat="server" Text="Button" />
    </div>
    </form>
</body>
</html>
<script type="text/javascript">
    var aaa = 1;
    document.getElementById("Image1").onclick = function () {
        this.setAttribute("src", "YZM.aspx?id=" + aaa);
        aaa++;
    };
</script>

鏈接頁面“YZM.aspx”——無需前台代碼，後台代碼是：

protected void Page_Load(object sender, EventArgs e)
    {
        Random r = new Random();
        string aaa = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890";
        //生成畫布
        Bitmap img = new Bitmap(80, 30);
        //畫布背景色泛性組合
        List<Color> Clist = new List<Color>();
        Clist.Add(Color.Yellow);
        Clist.Add(Color.Green);
        Clist.Add(Color.Blue);
        Clist.Add(Color.Aqua);
        Clist.Add(Color.Orange);
        Clist.Add(Color.Pink);

        Graphics g = Graphics.FromImage(img);

        g.FillRectangle(new SolidBrush(Clist[r.Next(0, Clist.Count)]), 0, 0, 80, 30);
        //隨機生成顯示的驗證碼組合
        string str = "";
        for (int i = 0; i < 4; i++)
        {
            str += aaa.Substring(r.Next(0, aaa.Length), 1);
        }

        Session["YZM"] = str;
        Font f = new Font("黑體", 20);
        Brush b = new SolidBrush(Color.Red);
        //生成
        g.DrawString(str, f, b, 10, 0);
        //添加干擾線
        for (int i = 0; i < r.Next(6, 20); i++)
        {
            Brush bb = new SolidBrush(Clist[r.Next(0, Clist.Count)]);
            Pen p = new Pen(bb, 1);
            g.DrawLine(p, r.Next(0, 80), r.Next(0, 30), r.Next(0, 80), r.Next(0, 30));
        }
        //保存完成
        img.Save(Response.OutputStream, System.Drawing.Imaging.ImageFormat.Jpeg);
        Response.End();
    }

效果展示：