Solved

JPEG Compression Issue

Posted on 2008-10-10
4
937 Views
Last Modified: 2013-11-08
Hello, I am changing the default compression set on an jpeg using the following code:

                    'Setup a JPEG codec with desired quality
                    Dim Codec, JPEGCodec As System.Drawing.Imaging.ImageCodecInfo
                    Dim EncParams As System.Drawing.Imaging.EncoderParameters

                    For Each Codec In System.Drawing.Imaging.ImageCodecInfo.GetImageEncoders
                        If Codec.MimeType = "image/jpeg" Then
                            JPEGCodec = Codec
                            Exit For
                        End If
                    Next 'Supposedly this cannot fail as image/jpg is built-in to GDI+ encoders

                    EncParams = New System.Drawing.Imaging.EncoderParameters(1)
                    EncParams.Param(0) = New System.Drawing.Imaging.EncoderParameter(System.Drawing.Imaging.Encoder.Quality, imageCompression)

                    HttpContext.Current.Response.ContentType = "image/jpeg"
                    outputImage.Save(HttpContext.Current.Response.OutputStream, JPEGCodec, EncParams)
                    'outputImage.Save(HttpContext.Current.Response.OutputStream, System.Drawing.Imaging.ImageFormat.Jpeg)

It works great but not in IE6.  The browser just crashes.  When I uncomment the last line an comment out the line before the last it work fine.  Is there a way to fix this or is there another way to change the default compression applied to an image when it is saved?

Thanks
0
Comment
Question by:grogo21
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 2
  • 2
4 Comments
 
LVL 11

Accepted Solution

by:
saleek earned 500 total points
ID: 22685054
hi,

what are you setting compression quality to?

For example, is it something like:

Dim imageCompression as Long = 99L  <-- 99 is quality percentage you would like

I dont see why IE6 would crash, if the aspx page outputs a valid bitmap then there should be no issue.

Does it work in IE7?

regards,

saleek
0
 

Author Comment

by:grogo21
ID: 22688602
Hello,
Yes I am using something like Dim imageCompression as Long = 99L.

I don't see why it would crash either. It works on IE7 and all other browsers.  For now I am using the following to get around it:

                    If HttpContext.Current.Request.UserAgent.Contains("MSIE 6") Then
                        outputImage.Save(HttpContext.Current.Response.OutputStream, System.Drawing.Imaging.ImageFormat.Jpeg)
                    Else
                    outputImage.Save(HttpContext.Current.Response.OutputStream, JPEGCodec, EncParams)
                    End If

I did use fiddler and the responses were identical with and without compression.  IE6 just crashes for some reason when I use a custom compression.  Is this something I can fix.  It seems to be an issue with the browser.

THanks
0
 

Author Comment

by:grogo21
ID: 22688872
Actually If I comment out this line flater in my code I can use compression just fine in IE6:

            'HttpContext.Current.Response.Close()

Any ideas why?

Thanks
0
 
LVL 11

Expert Comment

by:saleek
ID: 22794111
No - but I I have no idea why you would close the response.

Perhaps IE could not load the image (compress it?) beore you closed the response.

All the best.
0

Featured Post

Free Tool: Subnet Calculator

The subnet calculator helps you design networks by taking an IP address and network mask and returning information such as network, broadcast address, and host range.

One of a set of tools we're offering as a way of saying thank you for being a part of the community.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

IntroductionWhile developing web applications, a single page might contain many regions and each region might contain many number of controls with the capability to perform  postback. Many times you might need to perform some action on an ASP.NET po…
Real-time is more about the business, not the technology. In day-to-day life, to make real-time decisions like buying or investing, business needs the latest information(e.g. Gold Rate/Stock Rate). Unlike traditional days, you need not wait for a fe…
In a recent question (https://www.experts-exchange.com/questions/29004105/Run-AutoHotkey-script-directly-from-Notepad.html) here at Experts Exchange, a member asked how to run an AutoHotkey script (.AHK) directly from Notepad++ (aka NPP). This video…

735 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question