C#图片压缩处理
来源：程序员人生 发布时间：2014-09-16 21:43:57 阅读次数：2377次
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: 046620140807150650cin.jpg";
string source = @"G: 046620140807150650cin.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;
}
}
}
看下压缩后的图片如下
11KB
压缩前的图片
这样缩略图就成功了。
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