C#圖片壓縮處理

最近在做相簿功能遇到一個問題，就是載入圖片的時候然後放大，感覺有點卡。圖片可能有點大，所以考慮用縮圖來實現。

也就是在查詢出來一個相簿圖片  ，一頁顯示幾十張，這幾十張用縮圖來顯示，看相信情況的時候想QQ相簿樣載入原圖放大拉取圖片相關資訊。所用到的技術就是圖片壓縮功能。現在功能已經實現看代碼。

using System;using System.Collections.Generic;using System.ComponentModel;using System.Data;using System.Drawing;using System.Linq;using System.Text;using System.Windows.Forms;using System.Drawing.Imaging;using System.IO;namespace WindowsFormsApplication1{    public partial class Form1 : Form    {        public Form1()        {            InitializeComponent();        }        private void button1_Click(object sender, EventArgs e)        {            string pathPerc = @"D:\0046620140807150650cin.jpg";            string source = @"G:\0046620140807150650cin.jpg";            if (!File.Exists(pathPerc))            {                File.Create(pathPerc).Close();            }            else            {                File.Delete(pathPerc);                File.Create(pathPerc).Close();            }            getThumImage(source, 18, 3, pathPerc);        }        #region getThumImage        /**/        /// <summary>        /// 產生縮圖        /// </summary>        /// <param name="sourceFile">原始圖片檔案</param>        /// <param name="quality">品質壓縮比</param>        /// <param name="multiple">收縮倍數</param>        /// <param name="outputFile">輸出檔案名</param>        /// <returns>成功返回true,失敗則返回false</returns>        public static bool getThumImage(String sourceFile, long quality, int multiple, String outputFile)        {            try            {                long imageQuality = quality;                Bitmap sourceImage = new Bitmap(sourceFile);                ImageCodecInfo myImageCodecInfo = GetEncoderInfo("image/jpeg");                System.Drawing.Imaging.Encoder myEncoder = System.Drawing.Imaging.Encoder.Quality;                EncoderParameters myEncoderParameters = new EncoderParameters(1);                EncoderParameter myEncoderParameter = new EncoderParameter(myEncoder, imageQuality);                myEncoderParameters.Param[0] = myEncoderParameter;                float xWidth = sourceImage.Width;                float yWidth = sourceImage.Height;                Bitmap newImage = new Bitmap((int)(xWidth / multiple), (int)(yWidth / multiple));                Graphics g = Graphics.FromImage(newImage);                g.DrawImage(sourceImage, 0, 0, xWidth / multiple, yWidth / multiple);                g.Dispose();                newImage.Save(outputFile, myImageCodecInfo, myEncoderParameters);                return true;            }            catch            {                return false;            }        }        #endregion getThumImage        /**/        /// <summary>        /// 擷取圖片編碼資訊        /// </summary>        private static ImageCodecInfo GetEncoderInfo(String mimeType)        {            int j;            ImageCodecInfo[] encoders;            encoders = ImageCodecInfo.GetImageEncoders();            for (j = 0; j < encoders.Length; ++j)            {                if (encoders[j].MimeType == mimeType)                    return encoders[j];            }            return null;        }    }}

看下壓縮後的圖片如下

11KB

壓縮前的圖片

這樣縮圖就成功了。