网站微缩图

[woaishapi]

很早就发现opera浏览器的一个有趣的功能，将鼠标放在网页选项卡上的时候可以看到网页的缩略图；

今天在一个网站www.293.net（查询网站价值及网站详细报告的网站）里面也发现了这个功能，就是可以看到姚查询价值的网站微缩图。。。

这个是用什么技术做的呢？？？ 很好奇……

[子夜__]

步骤1 HTMl转图片

using System;
using System.ComponentModel;
using System.Drawing;
using System.Windows.Forms;
using System.Runtime.InteropServices;
using mshtml;
using SHDocVw;

namespace WindowsApplication1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            try
            {
                webBrowser1.Navigate("http://www.google.com/");
                while (webBrowser1.ReadyState != WebBrowserReadyState.Complete)
                {
                    Application.DoEvents();
                }

                mshtml.IHTMLDocument2 doc = webBrowser1.Document.DomDocument as IHTMLDocument2;
                IHTMLElementRender render = doc.body as IHTMLElementRender;

                using (System.Drawing.Bitmap img = new Bitmap(webBrowser1.Width, webBrowser1.Height))
                using (Graphics g = Graphics.FromImage(img))
                {
                    IntPtr hdc = g.GetHdc();
                    render.DrawToDC(hdc);
                    g.ReleaseHdc(hdc); 
                    img.Save("c:\\temp\\a.jpg");
                }
            }
            catch (Exception err)
            {
                MessageBox.Show(err.ToString());
            }
        }
    }

    /// <remarks>
    ///  prototype from Tlbimp  
    /// </remarks>
    [
    Guid("3050F669-98B5-11CF-BB82-00AA00BDCE0B"),
    InterfaceTypeAttribute(ComInterfaceType.InterfaceIsIUnknown),
    ComImport
    ]
    interface IHTMLElementRender
    {
        void DrawToDC([In] IntPtr hDC);
        void SetDocumentPrinter([In, MarshalAs(UnmanagedType.BStr)] string bstrPrinterName, [In] IntPtr hDC);
    };
}

html生成图片

步骤2 图片生成缩略图

public class ImagesTest
    {
        /// <summary>
        /// 生成缩略图
        /// </summary>
        /// <param name="originalImagePath">源图路径（物理路径）</param>
        /// <param name="thumbnailPath">缩略图路径（物理路径）</param>
        /// <param name="width">缩略图宽度</param>
        /// <param name="height">缩略图高度</param>
        /// <param name="mode">生成缩略图的方式:HW,W,H,Cut</param>    
        public void MakeThumbnail(string originalImagePath, string thumbnailPath, int width, int height, string mode)
        {
            System.Drawing.Image originalImage = System.Drawing.Image.FromFile(originalImagePath);

            int towidth = width;
            int toheight = height;

            int x = 0;
            int y = 0;
            int ow = originalImage.Width;
            int oh = originalImage.Height;

            switch (mode)
            {
                case "HW"://指定高宽缩放（可能变形）                
                    break;
                case "W"://指定宽，高按比例                    
                    toheight = originalImage.Height * width / originalImage.Width;
                    break;
                case "H"://指定高，宽按比例
                    towidth = originalImage.Width * height / originalImage.Height;
                    break;
                case "Cut"://指定高宽裁减（不变形）                
                    if ((double)originalImage.Width / (double)originalImage.Height > (double)towidth / (double)toheight)
                    {
                        oh = originalImage.Height;
                        ow = originalImage.Height * towidth / toheight;
                        y = 0;
                        x = (originalImage.Width - ow) / 2;
                    }
                    else
                    {
                        ow = originalImage.Width;
                        oh = originalImage.Width * height / towidth;
                        x = 0;
                        y = (originalImage.Height - oh) / 2;
                    }
                    break;
                default:
                    break;
            }

            //新建一个bmp图片
            System.Drawing.Image bitmap = new System.Drawing.Bitmap(towidth, toheight);

            //新建一个画板
            Graphics g = System.Drawing.Graphics.FromImage(bitmap);

            //设置高质量插值法
            g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High;

            //设置高质量,低速度呈现平滑程度
            g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;

            //清空画布并以透明背景色填充
            g.Clear(Color.Transparent);

            //在指定位置并且按指定大小绘制原图片的指定部分
            g.DrawImage(originalImage, new Rectangle(0, 0, towidth, toheight),
                new Rectangle(x, y, ow, oh),
                GraphicsUnit.Pixel);

            try
            {
                //以jpg格式保存缩略图
                bitmap.Save(thumbnailPath, System.Drawing.Imaging.ImageFormat.Jpeg);//走这里就错了
            }
            catch (System.Exception e)
            {
                throw e;
            }
            finally
            {
                originalImage.Dispose();
                bitmap.Dispose();
                g.Dispose();
            }
        }
    }

调用

/// <summary>
    /// 生成缩略图
    /// </summary>
    /// <param name="sender"></param>
    /// <param name="e"></param>
    protected void btnSearch_Click(object sender, EventArgs e)
    {
        if (this.txtImageName.Text=="")
        {
              Response.Write("<script>alert('请输入图片名称');top.location.reload();</script>");
        }
        else if(this.txtWidth.Text=="")
        {
            Response.Write("<script>alert('请输入图片宽度');top.location.reload();</script>");
        }
        else if (this.txtHeigh.Text=="")
        {
              Response.Write("<script>alert('请输入图片高度');top.location.reload();</script>");
        }
        else
        {
            string images = this.txtImageName.Text.ToString();
            int w = Convert.ToInt32(this.txtWidth.Text.ToString());//自己定义的图像宽度
            int h = Convert.ToInt32(this.txtHeigh.Text.ToString());//自己定义的图像高度

            ImagesTest imagesTest = new ImagesTest();
            string images1 = Server.MapPath("ImagesI/"+images);
            string images2 = Server.MapPath("ImagesII/"+images);
            int width = w;
            int heigh = h;
            string code = "";
            imagesTest.MakeThumbnail(images1, images2, width, heigh, code);
        }
    }

图片处理函数

步骤3 在需要的地方显示图片

[le616]

调用cmd命令生成 图片

        Process p = new Process();
        p.StartInfo.FileName = "cmd.exe";
        p.StartInfo.UseShellExecute = false;
        p.StartInfo.RedirectStandardInput = true;
        p.StartInfo.RedirectStandardOutput = true;
        p.StartInfo.RedirectStandardError = true;
        p.StartInfo.CreateNoWindow = true;
        string strOutput = null;
       string commandText="IeCapt.exe所在的目录" + Environment.NewLine +@"IECapt --url=http://www.qq.com/ --out=localfile.png（图片存放的路径)"；
        try
        {
            p.Start();
            p.StandardInput.WriteLine(commandText);
            p.StandardInput.WriteLine("exit");
            strOutput = p.StandardOutput.ReadToEnd();
            p.WaitForExit();
            p.Close();
        }
        catch (Exception e)
        {
            
        }

IeCapt.exe 下载