如何减少图像文件大小？ [英] How to reduce image file size?
问题描述
在从客户端上传文件后，我是否可以调用任何减少图像文件大小的例程。我希望在上传后使用C＃以编程方式减少文件大小
。我知道
Photoshop可以做到但我需要在我的网页中动态完成。我尝试用自己的一些Bitmap缩略图说明来做这件事，但是
产生的图像非常糟糕。我需要一个文件缩减程序，它可以创建一个更小的优质图像。我想如果Photoshop可以做到那么我可以这样吗b / b但是如何？
Is there any routine I can call to reduce the size of an image file after
uploading a file from a client. I am looking to reduce file sizes
programmatically using C# in my web page after uploading. I know that
Photoshop can do it but I need to do it dynamically in my web page. I tried
doing it myself with some of the Bitmap thumbnail instructions but the
resulting image is very bad. I need a file reduction routine that creates a
good image that is smaller. I figured if Photoshop can do it then so can I
but how?
推荐答案
查看Bitmap.GetThumbnailImage
-Brock
http：//工作人员。 develop.com/ballen
Check out Bitmap.GetThumbnailImage
-Brock
http://staff.develop.com/ballen
在上传文件后，我是否可以调用任何减少图像文件大小的例程？客户。我希望在上传后使用C＃在我的网页中以编程方式减少文件大小。我知道Photoshop可以做到但我需要在我的网页上动态地完成它。我尝试用一些Bitmap缩略图指令自己做，但结果图像非常糟糕。我需要一个文件减少例程来创建一个更小的好图像。我想
如果Photoshop可以做到那么我可以，但是如何？
Is there any routine I can call to reduce the size of an image file
after uploading a file from a client. I am looking to reduce file
sizes programmatically using C# in my web page after uploading. I know
that Photoshop can do it but I need to do it dynamically in my web
page. I tried doing it myself with some of the Bitmap thumbnail
instructions but the resulting image is very bad. I need a file
reduction routine that creates a good image that is smaller. I figured
if Photoshop can do it then so can I but how?
Brock;
感谢你答复。我尝试了Get ThumbnailImage函数，但
结果图像是模糊的。我将1360 X 2048图像缩小为272 X 408，并且
边缘模糊不清。我需要一些能让我获得更好分辨率的东西。
" Brock Allen"写道：
Brock;
Thanks for yur reply. I tried the Get ThumbnailImage function but the
resulting image is fuzzy. I reduced a 1360 X 2048 image to 272 X 408 and the
edges are blurry. I need something that gives me a better resolution.
"Brock Allen" wrote:
查看Bitmap.GetThumbnailImage
-Brock
http://staff.develop.com/ballen
Check out Bitmap.GetThumbnailImage
-Brock
http://staff.develop.com/ballen
我可以打电话到从客户端上传文件后，减小图像文件的大小。我希望在上传后使用C＃在我的网页中以编程方式减少文件大小。我知道Photoshop可以做到但我需要在我的网页上动态地完成它。我尝试用一些Bitmap缩略图指令自己做，但结果图像非常糟糕。我需要一个文件减少例程来创建一个更小的好图像。我想
如果Photoshop可以做到那么我可以，但是如何？
Is there any routine I can call to reduce the size of an image file
after uploading a file from a client. I am looking to reduce file
sizes programmatically using C# in my web page after uploading. I know
that Photoshop can do it but I need to do it dynamically in my web
page. I tried doing it myself with some of the Bitmap thumbnail
instructions but the resulting image is very bad. I need a file
reduction routine that creates a good image that is smaller. I figured
if Photoshop can do it then so can I but how?
鹦鹉 <帕**** @ discussions.microsoft.com>在消息中写道
news：53 ********************************** @ microsof t.com ...
"Parrot" <Pa****@discussions.microsoft.com> wrote in message
news:53**********************************@microsof t.com...
Brock;
感谢您的回复。我尝试了Get ThumbnailImage函数，但得到的图像是模糊的。我将1360 X 2048图像缩小为272 X 408并且
边缘模糊。我需要一些能让我获得更好分辨率的东西。
Brock Allen写道：
Brock;
Thanks for yur reply. I tried the Get ThumbnailImage function but the
resulting image is fuzzy. I reduced a 1360 X 2048 image to 272 X 408 and
the
edges are blurry. I need something that gives me a better resolution.
"Brock Allen" wrote:
查看Bitmap.GetThumbnailImage
Check out Bitmap.GetThumbnailImage
我使用GetThumbnailImage的第一个尝试非常难看，但是这个制作图片
看起来很好：
-Fred
使用系统;
使用系统.Data;
使用System.Configuration;
使用System.Web;
使用System.Web.Security;
使用System.Web.UI;
使用System.Web.UI.WebControls;
使用System.Web.UI.WebControls.WebParts;
使用System.Web.UI.HtmlControls;
使用System.IO;
使用System.Drawing;
///< summary>
/// makeThumbnail的摘要说明
///< / summary>
公共类makeThumbnail
{
public makeThumbnail（string parmFileIn，out int rc）
{
rc = 0;
string filePathSourceFile = HttpContext.Current.Server.MapPath（"〜/ images / "）;
string filePathDestFile =
HttpContext.Current.Server.MapPath（"〜/ thumbnails /"）;
< br $>
string fullSourceFile = filePathSourceFile + parmFileIn;
//字符串currentImageFile;
//字符串thumbnailFile;
int thumbnailHeight;
int thumbnailWidth;
int maxThumbSize = 150;
// int minThumbSize = 120; // 4 x 6比率
double hx; double wx;
//使用我们刚检索的文件名创建一个图像对象
System.Drawing.Image sourceImage =
System.Drawing.Image.FromFile（fullSourceFile）;
hx = sourceImage.Height;
wx = sourceImage。宽度;
//将缩略图宽度和高度计算：-scale到最大值
if（sourceImage.Width> sourceImage.Height ）// landscape：宽度固定，
比例高度：
{
thumbnailWidth = maxThumbSize;
// thumbnailHeight = minThumbSize;
thumbnailHeight = Convert.ToInt32（（hx / wx）* thumbnailWidth）;
}
其他//肖像：高度固定为最大，比例宽度：
{
thumbnailHeight = maxThumbSize;
thumbnailWidth = Convert.ToInt32（（wx / hx）* thumbnailHeight）;
}
System.Drawing.Image缩略图Image =
sourceImage.GetThumbnailImage（thumbnailWidth，thumbnailHeight，new
System.Drawing.Image.GetThumbnailImageAbort（Thumbn ailCallback），
IntPtr.Zero ）;
//使内存流处理图像字节
MemoryStream imageStream = new MemoryStream（）;
//将图像放入内存流中
thumbnailImage.Save（imageStream，System.Drawing.Imaging.ImageFormat.Jpeg）;
string outfile = filePathDestFile + parmFileIn;
试试
{
thumbnailImage 。保存（outfile）;
rc = 77;
}
catch（异常） e）
{
rc = 27;
string dummy = e.ToString（ ）;
返回;
}
}
///< summary>
///< / summary>
///< returns>真LT; /回报& gt;
public bool ThumbnailCallback（）
{
返回true;
}
}
My first trys using GetThumbnailImage were very ugly, but this makes images
that look just fine:
-Fred
using System;
using System.Data;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.IO;
using System.Drawing;
/// <summary>
/// Summary description for makeThumbnail
/// </summary>
public class makeThumbnail
{
public makeThumbnail(string parmFileIn, out int rc)
{
rc = 0;
string filePathSourceFile = HttpContext.Current.Server.MapPath("~/images/");
string filePathDestFile =
HttpContext.Current.Server.MapPath("~/thumbnails/");
string fullSourceFile = filePathSourceFile + parmFileIn;
//string currentImageFile;
//string thumbnailFile;
int thumbnailHeight;
int thumbnailWidth;
int maxThumbSize = 150;
//int minThumbSize = 120; // 4 x 6 ratio
double hx; double wx;
// create an image object, using the filename we just retrieved
System.Drawing.Image sourceImage =
System.Drawing.Image.FromFile(fullSourceFile);
hx = sourceImage.Height;
wx = sourceImage.Width;
// calc the thumbnail Width and Height: -scale to max with
if (sourceImage.Width > sourceImage.Height) // landscape: width is fixed,
scale height:
{
thumbnailWidth = maxThumbSize;
//thumbnailHeight = minThumbSize;
thumbnailHeight = Convert.ToInt32((hx / wx) * thumbnailWidth);
}
else // portrait: height is fixed at max, scale width:
{
thumbnailHeight = maxThumbSize;
thumbnailWidth = Convert.ToInt32((wx / hx) * thumbnailHeight);
}
System.Drawing.Image thumbnailImage =
sourceImage.GetThumbnailImage(thumbnailWidth, thumbnailHeight, new
System.Drawing.Image.GetThumbnailImageAbort(Thumbn ailCallback),
IntPtr.Zero);
// make a memory stream to work with the image bytes
MemoryStream imageStream = new MemoryStream();
// put the image into the memory stream
thumbnailImage.Save(imageStream, System.Drawing.Imaging.ImageFormat.Jpeg);
string outfile = filePathDestFile + parmFileIn;
try
{
thumbnailImage.Save(outfile);
rc = 77;
}
catch (Exception e)
{
rc = 27;
string dummy = e.ToString();
return;
}
}
/// <summary>
/// </summary>
/// <returns>true</returns>
public bool ThumbnailCallback()
{
return true;
}
}
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