最近在做相册功能遇到一个问题,就是加载图片的时候然后放大,感觉有点卡。图片可能有点大,所以考虑用缩略图来实现。
也就是在查询出来一个相册图片 ,一页显示几十张,这几十张用缩略图来显示,看相信情况的时候想QQ相册样加载原图放大拉取图片相关信息。所用到的技术就是图片压缩功能。现在功能已经实现看代码。
- 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>
- /// 生成缩略图
- /// </summary>
- /// <param name="sourceFile">原始图片文件</param>
- /// <param name="quality">质量压缩比</param>
- /// <param name="multiple">收缩倍数</param>
- /// <param name="outputFile">输出文件名</param>
- /// <returns>成功返回true,失败则返回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>
- /// 获取图片编码信息
- /// </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;
- }
- }
- }
11KB
压缩前的图片
这样缩略图就成功了。