动态生成图片 - NE_STOP

公告

using System;
using System.Web;
using System.Drawing;

返回的是img标签

    context.Response.ContentType = "text/html";
    string html = "<img src=\" 图片路径  \" />";
    context.Response.Write(html);

返回真正的图片本身

    context.Response.ContentType = "image/png";
    context.Response.WriteFile("图片路径");

完全动态生成一张图片

    context.Response.ContentType = "image/png";
    string name = "张三";
    //获取客户端ip
    string ip = context.Request.UserHostAddress;
    //动态生成图片,Image类是抽象类，不能实例化，这里是实例化他的子类，300是高度，100是宽度
    using (Image image=new Bitmap(300,100))
    {
        //无论要向该图片上画任何内容，都需要获取图片的‘画布’
        Graphics g=Graphics.FromImage(image);
        //设置背景色
        g.Clear(Color.Blue);
        //设置高质量的图片
        g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
        //向图片写姓名、ip,10,10代表坐标，red代表字体颜色红色，NewLine换行（建议使用，不建议\r\n）
        g.DrawString(name + Environment.NewLine + ip, new Font("全新硬笔行书简", 20), Brushes.Red, 10, 10);
        //把创建好的图片发给用户,保存到输出流，设置图片格式是jpeg
        image.Save(context.Response.OutputStream, System.Drawing.Imaging.ImageFormat.Jpeg);
    }

给图片加一个图片水印

context.Response.ContentType = "text/plain";
    //1.获取用户上传的图片
    HttpPostedFile file = context.Request.Files[0];
    //根据用户上传文件的字节，创建一个图片
    using (Image originalImg=Image.FromStream(file.InputStream))
    {
        //向图片写入水印（可以是文字或者图片）
        Graphics g = Graphics.FromImage(originalImg);
        //根据一个磁盘文件创建一个图片对象
        using(Image syImg=Image.FromFile(context.Request.MapPath("相对路径")))
        {
            //画图片
            g.DrawImage(syImg,0,0);

        }
        //加一个图片水印
        originalImg.Save(context.Request.MapPath("文件夹名") + Guid.NewGuid() + System.IO.Path.GetFileName(file.FileName));
    }
}

动态创建验证码

前端代码

<head runat="server">
<title></title>
<script type="text/javascript">
    function GetImage() {
        document.getElementById('img1').src = "Handler3.ashx?id=" + Math.random();
        return false;
    }
</script>
</head>
<body>
<form id="form1" runat="server">
<div>
    <img id="img1" src="Handler3.ashx" alt="Alternate Text" />
    <a href="#" onclick="GetImage()">看不清？</a>
</div>
</form>
</body>
</html>

后台代码

using System;
using System.Web;
using System.Drawing;
using System.IO;
    public void ProcessRequest (HttpContext context) {
    Random rdn = new Random();

    CreatYAM(rdn.Next(1000, 10000).ToString(), context);
    ｝

/// <summary>
/// 创建验证码
/// </summary>
/// <param name="validateCode"></param>
/// <param name="context"></param>
public void CreatYAM(string validateCode, HttpContext context)
{
    Bitmap image = new Bitmap((int)Math.Ceiling(validateCode.Length * 12.0), 22);
    Graphics g = Graphics.FromImage(image);
    try
    {
        //随机生成器
        Random random = new Random();
        //清空图片背景色
        g.Clear(Color.Wheat);
        //画图片的干扰线
        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);
        }
        Font font = new Font("Arial", 10, (FontStyle.Bold | 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(validateCode, font, brush, 3, 2);
        //画图片的前景干扰点
        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);
        //保存图片数据
        MemoryStream stream = new MemoryStream();
        image.Save(stream, System.Drawing.Imaging.ImageFormat.Jpeg);
        //输出图片流
        context.Response.Clear();
        context.Response.ContentType = "image/jpeg";
        context.Response.BinaryWrite(stream.ToArray());
    }
    finally
    {
        g.Dispose();
        image.Dispose(); 
    }
}

缩略图

前端代码

<form id="form1" runat="server" action="Handler.ashx" method="post" enctype="multipart/form-data">
<div>
    <input type="file" name="fileData" value="" />
    <input type="submit"  value="上传" />
</div>
</form>

后台代码

using System;
using System.Web;
using System.Drawing;

public class Handler : IHttpHandler {

public void ProcessRequest (HttpContext context) {
    context.Response.ContentType = "text/plain";
    //获取上传的文件流
    HttpPostedFile file = context.Request.Files[0];
    //根据文件流创建一个图片（原始图片）
    using (Image origimalImage=Image.FromStream(file.InputStream))
    {
        //获取原始图片的宽和高
        int oWidth = origimalImage.Width;
        int oHeight = origimalImage.Height;
        //缩略图的宽
        int tWidth = 100;
        int tHeight = oHeight * 100 / oWidth;

        //根据原始图片，等比例创建小图片
        using (Image thumbnailImage=new Bitmap(tWidth,tHeight))
        {
            //把大图片的内容画到小图片上
            //基于小图创建一个画布对象
            Graphics gThumbnail = Graphics.FromImage(thumbnailImage);
            //把大图画到小图上
            gThumbnail.DrawImage(origimalImage, 0, 0, tWidth, tHeight);
            //保存2张图片
            origimalImage.Save(context.Request.MapPath("../Upload/") + Guid.NewGuid() + "_origianl_" + System.IO.Path.GetFileName(file.FileName));
            thumbnailImage.Save(context.Request.MapPath("../Upload/") + Guid.NewGuid() + "_thumbnail_" + System.IO.Path.GetFileName(file.FileName))
        }  
    }
    context.Response.Write("文件上传成功！");
}

public bool IsReusable {
    get {
        return false;
    }
}

}

posted on 2017-07-09 22:04 NE_STOP 阅读(2) 评论(0) 编辑收藏举报来源

刷新页面返回顶部

返 回的是img标签

返回真正的图片本身

完全动态生成一张图片

给图片加一个图片水印

动态创建验证码

前端代码

后台代码

缩略图

前端代码

后台代码

返回的是img标签