C#压缩图片算法
2018-07-20 来源：open-open
using System.IO;
using System.Drawing;
using System.Drawing.Imaging;
using System;
namespace Bll
{
/// <summary>
/// 图片处理类
/// 1、生成缩略图片或按照比例改变图片的大小和画质
/// 2、将生成的缩略图放到指定的目录下
/// </summary>
public class ImageHepler
{
public Image ResourceImage, ReducedImage;
private int ImageWidth;
private int ImageHeight;
public string ErrMessage;
/// <summary>
/// 类的构造函数
/// </summary>
/// <param name="ImageFileName">图片文件的全路径名称</param>
public ImageHepler(string ImageFileName)
{
ResourceImage = Image.FromFile(ImageFileName);
ErrMessage = "";
}
public bool ThumbnailCallback()
{
return false;
}
/// <summary>
/// 生成缩略图，返回缩略图的Image对象
/// </summary>
/// <param name="Width">缩略图的宽度</param>
/// <param name="Height">缩略图的高度</param>
/// <returns>缩略图的Image对象</returns>
public Image GetReducedImage(int Width, int Height)
{
double LengthLong; //存储（长和宽中）较短的长度
int widthOK, heightOK; //存储实际要生成的图片的长宽
if (Width < Height) //判断输入的长和宽那个较短
{
LengthLong = Width; //把较短的存储在 LengthLonh 用于计算
}
else
{
LengthLong = Height;
}
try
{
//判断原图片 长和宽
//原图比较长的一个边要和缩略图的边相等
if (ResourceImage.Width > ResourceImage.Height)
{
widthOK = (int)LengthLong;
heightOK = (int)(LengthLong / ResourceImage.Width * ResourceImage.Height);
}
else
{
heightOK = (int)LengthLong;
widthOK = (int)LengthLong / ResourceImage.Height * ResourceImage.Width;
}
Image ReducedImage;
Image.GetThumbnailImageAbort callb = new Image.GetThumbnailImageAbort(ThumbnailCallback);
ReducedImage = ResourceImage.GetThumbnailImage(widthOK, heightOK, callb, IntPtr.Zero);
return ReducedImage;
}
catch (Exception e)
{
ErrMessage = e.Message;
return null;
}
}
/// <summary>
/// 生成缩略图，将缩略图文件保存到指定的路径
/// </summary>
/// <param name="Width">缩略图的宽度</param>
/// <param name="Height">缩略图的高度</param>
/// <param name="targetFilePath">缩略图保存的全文件名，(带路径)，参数格式：D:\Images\filename.jpg</param>
/// <returns>成功返回true，否则返回false</returns>
public bool GetReducedImage(int Width, int Height, string targetFilePath)
{
double LengthLong; //存储（长和宽中）较短的长度
int widthOK, heightOK; //存储实际要生成的图片的长宽
if (Width < Height) //判断输入的长和宽那个较短
{
LengthLong = Width; //把较短的存储在 LengthLonh 用于计算
}
else
{
LengthLong = Height;
}
try
{
//判断原图片 长和宽
//原图比较长的一个边要和缩略图的边相等
if (ResourceImage.Width > ResourceImage.Height)
{
widthOK = (int)LengthLong;
heightOK = (int)(LengthLong / ResourceImage.Width * ResourceImage.Height);
}
else
{
heightOK = (int)LengthLong;
widthOK = (int)LengthLong / ResourceImage.Height * ResourceImage.Width;
}
Image.GetThumbnailImageAbort callb = new Image.GetThumbnailImageAbort(ThumbnailCallback);
ReducedImage = ResourceImage.GetThumbnailImage(widthOK, heightOK, callb, IntPtr.Zero);
ReducedImage.Save(@targetFilePath, ImageFormat.Jpeg);
//ReducedImage.Dispose();
return true;
}
catch (Exception e)
{
ErrMessage = e.Message;
return false;
}
}
/// <summary>
/// 生成缩略图，返回缩略图的Image对象
/// </summary>
/// <param name="Percent">缩略图的宽度百分比 如：需要百分之80，就填0.8</param>
/// <returns>缩略图的Image对象</returns>
public Image GetReducedImage(double Percent)
{
try
{
Image ReducedImage;
Image.GetThumbnailImageAbort callb = new Image.GetThumbnailImageAbort(ThumbnailCallback);
ImageWidth = Convert.ToInt32(ResourceImage.Width * Percent);
ImageHeight = Convert.ToInt32(ResourceImage.Width * Percent);
ReducedImage = ResourceImage.GetThumbnailImage(ImageWidth, ImageHeight, callb, IntPtr.Zero);
return ReducedImage;
}
catch (Exception e)
{
ErrMessage = e.Message;
return null;
}
}
/// <summary>
/// 生成缩略图，返回缩略图的Image对象
/// </summary>
/// <param name="Percent">缩略图的宽度百分比 如：需要百分之80，就填0.8</param>
/// <param name="targetFilePath">缩略图保存的全文件名，(带路径)，参数格式：D:\Images\filename.jpg</param>
/// <returns>成功返回true,否则返回false</returns>
public bool GetReducedImage(double Percent, string targetFilePath)
{
try
{
Image.GetThumbnailImageAbort callb = new Image.GetThumbnailImageAbort(ThumbnailCallback);
ImageWidth = Convert.ToInt32(ResourceImage.Width * Percent);
ImageHeight = Convert.ToInt32(ResourceImage.Width * Percent);
ReducedImage = ResourceImage.GetThumbnailImage(ImageWidth, ImageHeight, callb, IntPtr.Zero);
ReducedImage.Save(@targetFilePath, ImageFormat.Jpeg);
//ReducedImage.Dispose();
return true;
}
catch (Exception e)
{
ErrMessage = e.Message;
return false;
}
}
}
}
[csharp] view plaincopy
using System;
using System.Data;
using System.Configuration;
using System.Linq;
using System.Web;
using System.IO;
using System.Collections;
using System.Collections.Generic;
using System.Security.AccessControl;
using System.Security.Permissions;
namespace Bll
{
public class FolderHelper
{
//判断文件夹是否存在
public static bool checkFolderExits(string path)
{
DirectoryInfo dir = new DirectoryInfo(path);
if (dir.Exists)//文件夹存在
{
return true;
}
else
{
//dir.Create();//不存在就创建一个
return false;
}
}
//创建一个文件夹，存在就创建失败
public static bool CreateNewFolder(string path)
{
DirectoryInfo dir = new DirectoryInfo(path);
if (!dir.Exists)
{
dir.Create();
return true;
}
else
return false;
}
/// <summary>
/// 在指定目录下创建指定名称文件夹
/// </summary>
/// <param name="ParentsPath"></param>
/// <param name="NewFolderName"></param>
/// <returns></returns>
public static bool CreateNewFolder(string ParentsPath, string NewFolderName)
{
string CreatePath = ParentsPath + @"\" + NewFolderName;
DirectoryInfo dir = new DirectoryInfo(CreatePath);
if (!dir.Exists)
{
dir.Create();
return true;
}
else
return false;
}
/// <summary>
/// 返回目录下的所有文件名
/// </summary>
/// <param name="path"></param>
/// <returns></returns>
public static ArrayList getAllFiles(string path)
{
DirectoryInfo dir = new DirectoryInfo(path);
if (dir.Exists)
{
FileInfo[] fileinfo = dir.GetFiles();
ArrayList list = new ArrayList();
foreach (FileInfo f in fileinfo)
{
list.Add(f.Name);
}
return list;
}
else
return null;
}
/// <summary>
/// 计算文件夹的大小
/// </summary>
/// <param name="d"></param>
/// <returns></returns>
public static long DirSize(DirectoryInfo d)
{
long Size = 0;
// Add file sizes.
FileInfo[] fis = d.GetFiles();//获得目录文件列表
foreach (FileInfo fi in fis)
{
Size += fi.Length;
}
// Add subdirectory sizes.
DirectoryInfo[] dis = d.GetDirectories();//获取目录子目录列表
foreach (DirectoryInfo di in dis)
{
Size += DirSize(di);
}
return Size;
}
/// <summary>
/// 把文件夹得大小转换成比较合适的表示单位
/// </summary>
/// <param name="size"></param>
/// <returns></returns>
public static string ViewSize(long size)
{
long m=size;
string viewstr;
if ((m / 1024) > 0)//表示可以转换成KB
{
m = m / 1024;//转换成KB
if ((m / 1024) > 0)//表示可以转换成MB
{
m = m / 1024;//转换成MB了
if ((m / 1024) > 0)//表示可以转换成GB
{
m = m / 1024;//转换成GB了
viewstr = m.ToString() + "GB";
}
else
{
viewstr = m.ToString() + "MB";
}
}
else
{
viewstr = m.ToString() + "KB";
}
}
else
{
viewstr = m.ToString() + "byte";
}
return viewstr;
}
/// <summary>
/// 删除指定目录和内容
/// </summary>
/// <param name="dir"></param>
/// <returns></returns>
public static bool delDir(string dir)
{
bool flag = false;
DirectoryInfo d = new DirectoryInfo(dir);
if (d.Exists)//判断目录是否存在
{
try
{
d.Delete();
flag = true;
}
catch (Exception e) { flag = false; }
}
return flag;
}
/// <summary>
/// 删除指定文件
/// </summary>
/// <param name="fil"></param>
/// <returns></returns>
public static bool delFile(string fil)
{
bool flag = false;
FileInfo d = new FileInfo(fil);
if (d.Exists)//判断目录是否存在
{
try
{
d.Delete();
flag = true;
}
catch (Exception e) { flag = false; }
}
return flag;
}
public static void Copy(string sourceDirectory, string targetDirectory)
{
DirectoryInfo diSource = new DirectoryInfo(sourceDirectory);
DirectoryInfo diTarget = new DirectoryInfo(targetDirectory);
CopyAll(diSource, diTarget);
}
/// <summary>
/// 复制目录及子文件到指定目录
/// </summary>
/// <param name="source"></param>
/// <param name="target"></param>
public static void CopyAll(DirectoryInfo source, DirectoryInfo target)
{
// Check if the target directory exists, if not, create it.
if (Directory.Exists(target.FullName) == false)
{
Directory.CreateDirectory(target.FullName);
}
// Copy each file into it's new directory.
foreach (FileInfo fi in source.GetFiles())
{
Console.WriteLine(@"Copying {0}\{1}", target.FullName, fi.Name);
fi.CopyTo(Path.Combine(target.ToString(), fi.Name), true);
}
// Copy each subdirectory using recursion.
foreach (DirectoryInfo diSourceSubDir in source.GetDirectories())
{
DirectoryInfo nextTargetSubDir =
target.CreateSubdirectory(diSourceSubDir.Name);
CopyAll(diSourceSubDir, nextTargetSubDir);
}
}
/// <summary>
/// 循环读取某个目录下的所有文件和目录，查询有关每一项的一些信息。返回一个文件列表
/// </summary>
/// <param name="strCurrentDir"></param>
public static List<fileEntity> FileView(string strCurrentDir)
{
List<fileEntity> fileList = new List<fileEntity>();
DirectoryInfo dir = new DirectoryInfo(strCurrentDir);
foreach (FileSystemInfo fsi in dir.GetFileSystemInfos())//这个循环再读取文件的信息
{
try
{
//FileSystemInfo 对象可以表示文件或目录，从而可以作为 FileInfo 或 DirectoryInfo 对象的基础。 当分析许多文件和目录时，请使用该基类。
FileInfo fi;
DirectoryInfo di;
//创建一个自己写的实体类的实体
fileEntity newfile = new fileEntity();
if (fsi is FileInfo)//外层循环读取文件信息
{
//表示当前fsi是文件
fi = (FileInfo)fsi;
newfile.fileName = fi.Name;
newfile.fileExt = fi.Extension;
newfile.fileSize = fi.Length;
newfile.FileModify = fi.LastWriteTime;
//通过扩展名来选择文件显示图标
switch (newfile.fileExt)
{
case ".gif":
newfile.picName = "gif.gif";
break;
default:
newfile.picName = "other.gif";
break;
}
newfile.picName = "<img src='" + newfile.picName + "' width=25 height=20>";
}
else
{
di = (DirectoryInfo)fsi;
newfile.fileName = di.Name;
newfile.fileSize = DirSize(di);//调用计算文件夹大小的方法
newfile.FileModify = di.LastWriteTime;
newfile.picName = "<img src='directory.gif' width=25 height=20>";
}
fileList.Add(newfile);
}
catch (Exception e) { }
}
return fileList;
}
/// <summary>
/// 显示目录和文件
/// </summary>
/// <param name="path"></param>
public static void All(string path)
{
FileInfo fi;//文件
DirectoryInfo di;//目录
DirectoryInfo dir=null;
int i = 0; //控制行的颜色
try
{
dir = new DirectoryInfo(path);
}
catch (Exception e) { }
foreach (FileSystemInfo fsi in dir.GetFileSystemInfos())
{
try
{
fileEntity newfile = new fileEntity();
FolderEntity folder = new FolderEntity();
newfile.fileName = "";
newfile.picName = "";
newfile.fileExt = "";
newfile.fileSize = 0;
folder.folderName = "";
folder.picName = "";
i += 1;
if (fsi is FileInfo)//判断当前读取的是不是一个文件
{
//表示当前fsi是文件
fi = (FileInfo)fsi;
newfile.fileName = fi.Name;
newfile.fileExt = fi.Extension;
newfile.fileSize = fi.Length;
newfile.FileModify = fi.LastWriteTime;
//将文件加上可以下载文件的链接
newfile.fileName = "<a href='........'></a>";
//通过扩展名来选择文件显示图标
//Response.Write(Session["DataBasePath"].ToString()+"\\filetype\\"+pfun.getFileExt(FileExt)+".gif");
if (fsi.Exists)
{
switch (newfile.fileExt)
{
case ".gif":
newfile.picName = "gif.gif";
break;
default:
newfile.picName = "other.gif";
break;
}
}
else
{
newfile.picName = "unknown.gif";
}
/*
switch(FileExt)
{
case ".gif":
FilePic = "gif.gif";
break;
default:
FilePic = "other.gif";
break;
}
*/
newfile.picName = "<img src='filetype/" + newfile.picName + "' width=16 height=16>";
}
else
{
//当前为目录
di = (DirectoryInfo)fsi;
folder.folderName = di.Name;
//给目录加上链接
folder.folderName = "<a href='.......'><a>";
folder.lastTime = di.LastWriteTime;
folder.picName = "<img src='filetype/folder.gif' width=16 height=16>";
}
}catch(Exception e){}
}
}
}
}
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