ASP.NET Discussion - GDI, Drawing an Image

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GDI, Drawing an Image

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Category: General Discussion
Forum Name: ASP.NET Discussion
Forum Description: Discussion and chat on ASP.NET related topics.
URL: https://forums.webwiz.net/forum_posts.asp?TID=12199
Printed Date: 28 March 2026 at 11:06pm
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Topic: GDI, Drawing an Image

Posted By: vshriniwasan
Subject: GDI, Drawing an Image
Date Posted: 16 October 2004 at 9:32am

Hey guys, I am working on a simple GDI Script in SharePoint. This is only Code Behind. I am trying to write the stream. I have two errors. It is saying Response is not declared. Is there any other way to declare this... Can I import something that might fix the problem.

Response.ContentType = "image/gif"
fullSizeImg.Save(Response.OutputStream, ImageFormat.Gif)

Please Advise, Thank you...

Shrini

Replies:

Posted By: michael
Date Posted: 16 October 2004 at 10:57am

Imports HTTPCOntext.Current
at the top of the Code behind page.

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Posted By: vshriniwasan
Date Posted: 16 October 2004 at 11:57am

Michael you are a genius...

It worked perfect with a little hitch..

As per your advise, I imporeted System.web.httpcontext and changed my response to current.response.

Now for what's happening and the little bit code:

myImage = New Image
Controls.Add(myImage)
myImage.ImageURL = WriteGDI(passing Values)

function WriteGDI()
...............................
...............................
myBitMap.Save(memStream, ImageFormat.Png)
memStream.WriteTo(Current.Response.OutputStream)
End Function

What this is doing is replacing my page with the image itself. What can I do to just have the image change in the middle of the page.

Thanks a lot for take time to assist me.
Shrini

Posted By: michael
Date Posted: 16 October 2004 at 1:50pm

Not sure what you mean with just replacing the middle of the page. If you want to display a gdi image within another page you either need to add a placeholder or image control to the page and then dynamically add the .aspx as gdi to it. Generating a gdi image will result in the aspx page to be an image so you need to add it to another page.

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Posted By: vshriniwasan
Date Posted: 16 October 2004 at 7:00pm

Michael,

I already have a place holder for the image in the middle of the page.

I have a function I am passing the information to the Funciton which which generates a simple image. There are no other ASPX pages where I can move the Script and pass the values through QueryString to the page.

It looks like I am screwed in a manner.

Hope there is a solution.

Shrini

Posted By: vshriniwasan
Date Posted: 16 October 2004 at 7:57pm

Michael,

Here is an interesting option. May Be!

I can serialize the image. Can I deserialize it and assign it as the imageURL.

Don't know how I can do that yet and is it going to drop me in the same position.

Shrini

Posted By: michael
Date Posted: 16 October 2004 at 8:20pm

If you do not want to generate the image in a 2nd page so you can set the URL you will need to use a HTTP Handler. This is once you understand HTTP Handlers fairly easy to do, here is a c# example how the asp.net forums generate an avatar which is passes as a binary from database


using System;

using System.Web;

using System.Web.Caching;

using AspNetForums;



namespace AspNetForums.Components.HttpHandler {



    public class AvatarHttpHandler : IHttpHandler {



        public void ProcessRequest (HttpContext context) {



              try {

                  Avatar userAvatar = Resources.GetAvatar( int.Parse(context.Request.QueryString["UserID"]) );



                  context.Response.ContentType = userAvatar.ContentType;

                  context.Response.OutputStream.Write(userAvatar.Content, 0, userAvatar.Length);



                   context.Response.Cache.SetCacheability(HttpCacheability.Publ ic);

                                       context.Response.Cache.SetExpires(DateTime.Now.AddMinutes(30));

                   context.Response.Cache.SetAllowResponseInBrowserHistory(true );

                  context.Response.Cache.SetValidUntilExpires(true);

                  context.Response.Cache.VaryByParams["UserID"] = true;

              } catch {}



        }



        public bool IsReusable {

              get {

                  return false;

              }

        }

    }

}

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