Disposable Canvas?

[Jon Davis]

OK, why is Canvas not IDisposable, and how do I get rid of all the Windows
handles?

I'm doing a performance test of looping through a dynamic XAML-to-JPEG
conversion. It gets to about 500 conversions and then crashes. Task Manager
says that about 6000 Windows handles were created and the count never
decrements.

My code (loop not shown):

protected System.IO.Strea m GenImageStream( )
{
System.IO.Strea m retImageStream = null;
System.IO.Strea mReader sr = new
System.IO.Strea mReader("Window 1.xaml");
string xaml = sr.ReadToEnd();
if (text != null)
{
xaml = xaml.Replace("{ $TEXT$}", text
}
else
{
xaml = xaml.Replace("{ $TEXT$}", "Enter text.");
}
sr.Close();
System.IO.Memor yStream ms = new
System.IO.Memor yStream(xaml.Le ngth);
System.IO.Strea mWriter sw = new System.IO.Strea mWriter(ms);
sw.Write(xaml);
sw.Flush();
ms.Seek(0, System.IO.SeekO rigin.Begin);
System.Windows. Controls.Canvas canvas =
(System.Windows .Controls.Canva s)
System.Windows. Markup.XamlRead er.Load(ms);
canvas.Backgrou nd = System.Windows. Media.Brushes.Y ellow;
canvas.Measure( new System.Windows. Size(640d, 480d));
canvas.Arrange( new System.Windows. Rect(0d, 0d, 640d, 480d));
System.Windows. Media.Imaging.R enderTargetBitm ap rtb
= new System.Windows. Media.Imaging.R enderTargetBitm ap(
640, 480, 96d, 96d,
System.Windows. Media.PixelForm ats.Default);
rtb.Render(canv as);
System.Windows. Media.Imaging.J pegBitmapEncode r encoder
= new System.Windows. Media.Imaging.J pegBitmapEncode r();
encoder.Frames. Add(System.Wind ows.Media.Imagi ng.BitmapFrame. Create(rtb));
string fp = Request.Physica lApplicationPat h + "imgtmp\\"
+ (Guid.NewGuid() ).ToString() + ".jpg";
retImageStream = new System.IO.Memor yStream();
encoder.Save(re tImageStream);
retImageStream. Seek(0, System.IO.SeekO rigin.Begin);
ms.Dispose();
}

Jon

[Oliver Sturm [MVP C#]]

Hi,

Jon Davis wrote:

OK, why is Canvas not IDisposable, and how do I get rid of all the Windows
handles?

I used a variation of your code to try this myself, but I was unable to
reproduce the crash behaviour your were referring to. I also used a
profiler to look out for resource leaks and I didn't find any of these
either. Here's the code I used:

private void OnButtonClick( object sender, RoutedEventArgs e) {
for (int i = 0; i < 1000; i++)
GenImageStream( );
}
private static string GetXaml( ) {
StreamReader sr = new StreamReader("C anvas.xaml");
string xaml = sr.ReadToEnd( );
sr.Close( );
return xaml;
}

protected void GenImageStream( ) {
string xaml = GetXaml( );

using (MemoryStream ms = new MemoryStream(xa ml.Length)) {
StreamWriter sw = new StreamWriter(ms );
sw.Write(xaml);
sw.Flush( );
ms.Seek(0, SeekOrigin.Begi n);

Canvas canvas = (Canvas) XamlReader.Load (ms);
canvas.Backgrou nd = Brushes.Yellow;
canvas.Measure( new Size(640d, 480d));
canvas.Arrange( new Rect(0d, 0d, 640d, 480d));
RenderTargetBit map rtb = new RenderTargetBit map(
640, 480, 96d, 96d, PixelFormats.De fault);
rtb.Render(canv as);
JpegBitmapEncod er encoder = new JpegBitmapEncod er( );
encoder.Frames. Add(BitmapFrame .Create(rtb));
using (Stream outstream = new MemoryStream( ))
encoder.Save(ou tstream);
}
}
Oliver Sturm
--
http://www.sturmnet.org/blog - MVP C#

[Jon Davis]

"Oliver Sturm [MVP C#]" <ol****@sturmne t.orgwrote in message
news:1o******** ********@sturmn et.org...

Hi,

Jon Davis wrote:

>OK, why is Canvas not IDisposable, and how do I get rid of all the
Windows
handles?

I used a variation of your code to try this myself, but I was unable to
reproduce the crash behaviour your were referring to.

That's interesting. It might help if I mention I'm trying to do this on an
ASP.NET web page to see about the feasibility of dynamically-generating
images from XAML mark-up, on a heavily impacted web site. The output of
this is great and seems to be fast, it's just that it crashes after 500
times and IIS's process has 6000 Windows handles. I'm executing on Windows
Vista / IIS 7. Here's the full source. I'll take a look at yours as well,
but in the mean time ... maybe you can spot something really, really stupid
I'm doing? :)

using System;
using System.Data;
using System.Configur ation;
using System.Collecti ons;
using System.Web;
using System.Web.Secu rity;
using System.Web.UI;
using System.Web.UI.W ebControls;
using System.Web.UI.W ebControls.WebP arts;
using System.Web.UI.H tmlControls;

namespace ImageGenServer
{
public partial class GenImage : System.Web.UI.P age
{
private System.IO.Strea m retImageStream;
protected void Page_Load(objec t sender, EventArgs e)
{
Gimme();
}

protected void Gimme()
{
System.Threadin g.Thread thread = new System.Threadin g.Thread(
GimmeMore);
thread.SetApart mentState(Syste m.Threading.Apa rtmentState.STA );
thread.Start();
while (thread.IsAlive )
{
System.Threadin g.Thread.Sleep( 0);
}
Response.Conten tType = "image/jpeg";
System.IO.Binar yReader br = new
System.IO.Binar yReader(retImag eStream);
Response.Binary Write(br.ReadBy tes((int)retIma geStream.Length ));
br.Close();
retImageStream. Close();
Response.Flush( );

thread = null;
br = null;
retImageStream = null;

Response.End();
}

protected void GimmeMore()
{
System.IO.Strea mReader sr = new
System.IO.Strea mReader(Request .PhysicalApplic ationPath + "Window1.xaml") ;
string xaml = sr.ReadToEnd();
if (Request["text"] != null)
{
xaml = xaml.Replace("{ $TEXT$}", Request["text"]);
}
else
{
xaml = xaml.Replace("{ $TEXT$}", "Add &quot;text=...& quot; to
querystring.");
}
sr.Close();
System.IO.Memor yStream ms = new
System.IO.Memor yStream(xaml.Le ngth);
System.IO.Strea mWriter sw = new System.IO.Strea mWriter(ms);
sw.Write(xaml);
sw.Flush();
ms.Seek(0, System.IO.SeekO rigin.Begin);
System.Windows. Controls.Canvas canvas =
(System.Windows .Controls.Canva s)
System.Windows. Markup.XamlRead er.Load(
ms);
canvas.Backgrou nd = System.Windows. Media.Brushes.Y ellow;
canvas.Measure( new System.Windows. Size(640d, 480d));
canvas.Arrange( new System.Windows. Rect(0d, 0d, 640d, 480d));
System.Windows. Media.Imaging.R enderTargetBitm ap rtb
= new System.Windows. Media.Imaging.R enderTargetBitm ap(
640, 480, 96d, 96d,
System.Windows. Media.PixelForm ats.Default);
rtb.Render(canv as);
System.Windows. Media.Imaging.J pegBitmapEncode r encoder
= new System.Windows. Media.Imaging.J pegBitmapEncode r();
encoder.Frames. Add(System.Wind ows.Media.Imagi ng.BitmapFrame. Create(
rtb));
string fp = Request.Physica lApplicationPat h + "imgtmp\\"
+ (Guid.NewGuid() ).ToString() + ".jpg";
retImageStream = new System.IO.Memor yStream();
encoder.Save(re tImageStream);
retImageStream. Seek(0, System.IO.SeekO rigin.Begin);
ms.Dispose();

}
}
}

[Jon Davis]

Died with you code, too. I think this has to do with STA threading. Not sure
if there is such a thing as a "best practice" for STA threading on ASP.NET.

Jon
"Jon Davis" <jo*@REMOVE.ME. PLEASE.jondavis .netwrote in message
news:ex******** ******@TK2MSFTN GP05.phx.gbl...

>
"Oliver Sturm [MVP C#]" <ol****@sturmne t.orgwrote in message
news:1o******** ********@sturmn et.org...

>Hi,

Jon Davis wrote:

>>OK, why is Canvas not IDisposable, and how do I get rid of all the
Windows
handles?

I used a variation of your code to try this myself, but I was unable to
reproduce the crash behaviour your were referring to.

That's interesting. It might help if I mention I'm trying to do this on an
ASP.NET web page to see about the feasibility of dynamically-generating
images from XAML mark-up, on a heavily impacted web site. The output of
this is great and seems to be fast, it's just that it crashes after 500
times and IIS's process has 6000 Windows handles. I'm executing on Windows
Vista / IIS 7. Here's the full source. I'll take a look at yours as well,
but in the mean time ... maybe you can spot something really, really
stupid I'm doing? :)

using System;
using System.Data;
using System.Configur ation;
using System.Collecti ons;
using System.Web;
using System.Web.Secu rity;
using System.Web.UI;
using System.Web.UI.W ebControls;
using System.Web.UI.W ebControls.WebP arts;
using System.Web.UI.H tmlControls;

namespace ImageGenServer
{
public partial class GenImage : System.Web.UI.P age
{
private System.IO.Strea m retImageStream;
protected void Page_Load(objec t sender, EventArgs e)
{
Gimme();
}

protected void Gimme()
{
System.Threadin g.Thread thread = new System.Threadin g.Thread(
GimmeMore);
thread.SetApart mentState(Syste m.Threading.Apa rtmentState.STA );
thread.Start();
while (thread.IsAlive )
{
System.Threadin g.Thread.Sleep( 0);
}
Response.Conten tType = "image/jpeg";
System.IO.Binar yReader br = new
System.IO.Binar yReader(retImag eStream);
Response.Binary Write(br.ReadBy tes((int)retIma geStream.Length ));
br.Close();
retImageStream. Close();
Response.Flush( );

thread = null;
br = null;
retImageStream = null;

Response.End();
}

protected void GimmeMore()
{
System.IO.Strea mReader sr = new
System.IO.Strea mReader(Request .PhysicalApplic ationPath + "Window1.xaml") ;
string xaml = sr.ReadToEnd();
if (Request["text"] != null)
{
xaml = xaml.Replace("{ $TEXT$}", Request["text"]);
}
else
{
xaml = xaml.Replace("{ $TEXT$}", "Add &quot;text=...& quot;
to querystring.");
}
sr.Close();
System.IO.Memor yStream ms = new
System.IO.Memor yStream(xaml.Le ngth);
System.IO.Strea mWriter sw = new System.IO.Strea mWriter(ms);
sw.Write(xaml);
sw.Flush();
ms.Seek(0, System.IO.SeekO rigin.Begin);
System.Windows. Controls.Canvas canvas =
(System.Windows .Controls.Canva s)
System.Windows. Markup.XamlRead er.Load(
ms);
canvas.Backgrou nd = System.Windows. Media.Brushes.Y ellow;
canvas.Measure( new System.Windows. Size(640d, 480d));
canvas.Arrange( new System.Windows. Rect(0d, 0d, 640d, 480d));
System.Windows. Media.Imaging.R enderTargetBitm ap rtb
= new System.Windows. Media.Imaging.R enderTargetBitm ap(
640, 480, 96d, 96d,
System.Windows. Media.PixelForm ats.Default);
rtb.Render(canv as);
System.Windows. Media.Imaging.J pegBitmapEncode r encoder
= new System.Windows. Media.Imaging.J pegBitmapEncode r();

encoder.Frames. Add(System.Wind ows.Media.Imagi ng.BitmapFrame. Create(
rtb));
string fp = Request.Physica lApplicationPat h + "imgtmp\\"
+ (Guid.NewGuid() ).ToString() + ".jpg";
retImageStream = new System.IO.Memor yStream();
encoder.Save(re tImageStream);
retImageStream. Seek(0, System.IO.SeekO rigin.Begin);
ms.Dispose();

}
}
}

[Jon Davis]

Setting AspCompat="true " to the .aspx header to make the page STA threaded,
and dropping the spawning of a new thread, seemed to alleviate this
significantly. I executed 5000 times before I just killed the test (was
running low on drive space -- made that many images). Memory consumption by
the VS debugger web server did go up to 178MB and more than 1000 handles and
didn't go down after I stopped the test, so there's still a bad memory leak,
but not anything like before.

Interesting. However, now I get an error message in Visual Studio when I go
to debug:

Error connecting to undo manager of source file 'C:\Documents and
Settings\jdavis \My Documents\Visua l Studio
2005\Projects\I mageGenServer\T hreadMode.aspx. designer.cs'.
Jon
"Jon Davis" <jo*@REMOVE.ME. PLEASE.jondavis .netwrote in message
news:%2******** *******@TK2MSFT NGP05.phx.gbl.. .

Died with you code, too. I think this has to do with STA threading. Not
sure if there is such a thing as a "best practice" for STA threading on
ASP.NET.

Jon
"Jon Davis" <jo*@REMOVE.ME. PLEASE.jondavis .netwrote in message
news:ex******** ******@TK2MSFTN GP05.phx.gbl...

>>
"Oliver Sturm [MVP C#]" <ol****@sturmne t.orgwrote in message
news:1o******* *********@sturm net.org...

>>Hi,

Jon Davis wrote:

OK, why is Canvas not IDisposable, and how do I get rid of all the
Windows
handles?

I used a variation of your code to try this myself, but I was unable to
reproduce the crash behaviour your were referring to.

That's interesting. It might help if I mention I'm trying to do this on
an ASP.NET web page to see about the feasibility of
dynamically-generating images from XAML mark-up, on a heavily impacted
web site. The output of this is great and seems to be fast, it's just
that it crashes after 500 times and IIS's process has 6000 Windows
handles. I'm executing on Windows Vista / IIS 7. Here's the full source.
I'll take a look at yours as well, but in the mean time ... maybe you can
spot something really, really stupid I'm doing? :)

using System;
using System.Data;
using System.Configur ation;
using System.Collecti ons;
using System.Web;
using System.Web.Secu rity;
using System.Web.UI;
using System.Web.UI.W ebControls;
using System.Web.UI.W ebControls.WebP arts;
using System.Web.UI.H tmlControls;

namespace ImageGenServer
{
public partial class GenImage : System.Web.UI.P age
{
private System.IO.Strea m retImageStream;
protected void Page_Load(objec t sender, EventArgs e)
{
Gimme();
}

protected void Gimme()
{
System.Threadin g.Thread thread = new System.Threadin g.Thread(
GimmeMore);
thread.SetApart mentState(Syste m.Threading.Apa rtmentState.STA );
thread.Start();
while (thread.IsAlive )
{
System.Threadin g.Thread.Sleep( 0);
}
Response.Conten tType = "image/jpeg";
System.IO.Binar yReader br = new
System.IO.Bina ryReader(retIma geStream);

Response.Binar yWrite(br.ReadB ytes((int)retIm ageStream.Lengt h));
br.Close();
retImageStream. Close();
Response.Flush( );

thread = null;
br = null;
retImageStream = null;

Response.End();
}

protected void GimmeMore()
{
System.IO.Strea mReader sr = new
System.IO.Stre amReader(Reques t.PhysicalAppli cationPath + "Window1.xaml") ;
string xaml = sr.ReadToEnd();
if (Request["text"] != null)
{
xaml = xaml.Replace("{ $TEXT$}", Request["text"]);
}
else
{
xaml = xaml.Replace("{ $TEXT$}", "Add &quot;text=...& quot;
to querystring.");
}
sr.Close();
System.IO.Memor yStream ms = new
System.IO.Memo ryStream(xaml.L ength);
System.IO.Strea mWriter sw = new System.IO.Strea mWriter(ms);
sw.Write(xaml);
sw.Flush();
ms.Seek(0, System.IO.SeekO rigin.Begin);
System.Windows. Controls.Canvas canvas =
(System.Window s.Controls.Canv as)
System.Windows. Markup.XamlRead er.Load(
ms);
canvas.Backgrou nd = System.Windows. Media.Brushes.Y ellow;
canvas.Measure( new System.Windows. Size(640d, 480d));
canvas.Arrange( new System.Windows. Rect(0d, 0d, 640d, 480d));
System.Windows. Media.Imaging.R enderTargetBitm ap rtb
= new System.Windows. Media.Imaging.R enderTargetBitm ap(
640, 480, 96d, 96d,
System.Windows .Media.PixelFor mats.Default);
rtb.Render(canv as);
System.Windows. Media.Imaging.J pegBitmapEncode r encoder
= new System.Windows. Media.Imaging.J pegBitmapEncode r();

encoder.Frames .Add(System.Win dows.Media.Imag ing.BitmapFrame .Create(
rtb));
string fp = Request.Physica lApplicationPat h + "imgtmp\\"
+ (Guid.NewGuid() ).ToString() + ".jpg";
retImageStream = new System.IO.Memor yStream();
encoder.Save(re tImageStream);
retImageStream. Seek(0, System.IO.SeekO rigin.Begin);
ms.Dispose();

}
}
}

[Jon Davis]

Setting AspCompat="true " to the .aspx header to make the page STA threaded,
and dropping the spawning of a new thread, seemed to alleviate this
significantly. I executed 5000 times before I just killed the test (was
running low on drive space -- made that many images). Memory consumption by
the VS debugger web server did go up to 178MB and more than 1000 handles and
didn't go down after I stopped the test, so there's still a bad memory leak,
but not anything like before.

Would like to fix that lingering memory leak. The stuff HAS to be flushed or
else it's no good for production use, unless I want to reset IIS every hour
(which I don't).

Jon

"Jon Davis" <jo*@REMOVE.ME. PLEASE.jondavis .netwrote in message
news:%2******** *******@TK2MSFT NGP05.phx.gbl.. .

Died with you code, too. I think this has to do with STA threading. Not
sure if there is such a thing as a "best practice" for STA threading on
ASP.NET.

Jon
"Jon Davis" <jo*@REMOVE.ME. PLEASE.jondavis .netwrote in message
news:ex******** ******@TK2MSFTN GP05.phx.gbl...

>>
"Oliver Sturm [MVP C#]" <ol****@sturmne t.orgwrote in message
news:1o******* *********@sturm net.org...

>>Hi,

Jon Davis wrote:

OK, why is Canvas not IDisposable, and how do I get rid of all the
Windows
handles?

I used a variation of your code to try this myself, but I was unable to
reproduce the crash behaviour your were referring to.

That's interesting. It might help if I mention I'm trying to do this on
an ASP.NET web page to see about the feasibility of
dynamically-generating images from XAML mark-up, on a heavily impacted
web site. The output of this is great and seems to be fast, it's just
that it crashes after 500 times and IIS's process has 6000 Windows
handles. I'm executing on Windows Vista / IIS 7. Here's the full source.
I'll take a look at yours as well, but in the mean time ... maybe you can
spot something really, really stupid I'm doing? :)

using System;
using System.Data;
using System.Configur ation;
using System.Collecti ons;
using System.Web;
using System.Web.Secu rity;
using System.Web.UI;
using System.Web.UI.W ebControls;
using System.Web.UI.W ebControls.WebP arts;
using System.Web.UI.H tmlControls;

namespace ImageGenServer
{
public partial class GenImage : System.Web.UI.P age
{
private System.IO.Strea m retImageStream;
protected void Page_Load(objec t sender, EventArgs e)
{
Gimme();
}

protected void Gimme()
{
System.Threadin g.Thread thread = new System.Threadin g.Thread(
GimmeMore);
thread.SetApart mentState(Syste m.Threading.Apa rtmentState.STA );
thread.Start();
while (thread.IsAlive )
{
System.Threadin g.Thread.Sleep( 0);
}
Response.Conten tType = "image/jpeg";
System.IO.Binar yReader br = new
System.IO.Bina ryReader(retIma geStream);

Response.Binar yWrite(br.ReadB ytes((int)retIm ageStream.Lengt h));
br.Close();
retImageStream. Close();
Response.Flush( );

thread = null;
br = null;
retImageStream = null;

Response.End();
}

protected void GimmeMore()
{
System.IO.Strea mReader sr = new
System.IO.Stre amReader(Reques t.PhysicalAppli cationPath + "Window1.xaml") ;
string xaml = sr.ReadToEnd();
if (Request["text"] != null)
{
xaml = xaml.Replace("{ $TEXT$}", Request["text"]);
}
else
{
xaml = xaml.Replace("{ $TEXT$}", "Add &quot;text=...& quot;
to querystring.");
}
sr.Close();
System.IO.Memor yStream ms = new
System.IO.Memo ryStream(xaml.L ength);
System.IO.Strea mWriter sw = new System.IO.Strea mWriter(ms);
sw.Write(xaml);
sw.Flush();
ms.Seek(0, System.IO.SeekO rigin.Begin);
System.Windows. Controls.Canvas canvas =
(System.Window s.Controls.Canv as)
System.Windows. Markup.XamlRead er.Load(
ms);
canvas.Backgrou nd = System.Windows. Media.Brushes.Y ellow;
canvas.Measure( new System.Windows. Size(640d, 480d));
canvas.Arrange( new System.Windows. Rect(0d, 0d, 640d, 480d));
System.Windows. Media.Imaging.R enderTargetBitm ap rtb
= new System.Windows. Media.Imaging.R enderTargetBitm ap(
640, 480, 96d, 96d,
System.Windows .Media.PixelFor mats.Default);
rtb.Render(canv as);
System.Windows. Media.Imaging.J pegBitmapEncode r encoder
= new System.Windows. Media.Imaging.J pegBitmapEncode r();

encoder.Frames .Add(System.Win dows.Media.Imag ing.BitmapFrame .Create(
rtb));
string fp = Request.Physica lApplicationPat h + "imgtmp\\"
+ (Guid.NewGuid() ).ToString() + ".jpg";
retImageStream = new System.IO.Memor yStream();
encoder.Save(re tImageStream);
retImageStream. Seek(0, System.IO.SeekO rigin.Begin);
ms.Dispose();

}
}
}

[Willy Denoyette [MVP]]

"Jon Davis" <jo*@REMOVE.ME. PLEASE.jondavis .netwrote in message
news:em******** ******@TK2MSFTN GP02.phx.gbl...

Setting AspCompat="true " to the .aspx header to make the page STA
threaded,
and dropping the spawning of a new thread, seemed to alleviate this
significantly. I executed 5000 times before I just killed the test (was
running low on drive space -- made that many images). Memory consumption
by
the VS debugger web server did go up to 178MB and more than 1000 handles
and
didn't go down after I stopped the test, so there's still a bad memory
leak,
but not anything like before.

Would like to fix that lingering memory leak. The stuff HAS to be flushed
or else it's no good for production use, unless I want to reset IIS every
hour (which I don't).

Jon

XAML and WPF is a desktop technology and IMO not designed and not supported
server side, note that the same applies to System.Windows. Forms. A lot of
the System.Windows namespace classes need a pumping STA thread to run in,
and the System.Windows. Markup.XamlRead er should throw an exception when
called from a non-STA thread (don't know why it didn't in your case though).
The documentation should include a warning just like the one included in
Windows.Forms
<Classes within the Windows Forms namespace are not supported for use within
a Windows service. Trying to use these classes from within a service may
produce unexpected problems, such as diminished service performance and
run-time exceptions.

>

Willy.

[Jon Davis]

Oliver,

I'm running your code in a console app now and watching memory consumption
go up in a similar way to IIS. Handle count is frozen solid at 151, but
memory utilization is currently at 271MB at 10000 instances of the loop.
GC.Collect() after the loop completed had no significant effect; took it to
245MB on second pass.

Jon
"Oliver Sturm [MVP C#]" <ol****@sturmne t.orgwrote in message
news:1o******** ********@sturmn et.org...

Hi,

Jon Davis wrote:

>OK, why is Canvas not IDisposable, and how do I get rid of all the
Windows
handles?

I used a variation of your code to try this myself, but I was unable to
reproduce the crash behaviour your were referring to. I also used a
profiler to look out for resource leaks and I didn't find any of these
either. Here's the code I used:

private void OnButtonClick( object sender, RoutedEventArgs e) {
for (int i = 0; i < 1000; i++)
GenImageStream( );
}
private static string GetXaml( ) {
StreamReader sr = new StreamReader("C anvas.xaml");
string xaml = sr.ReadToEnd( );
sr.Close( );
return xaml;
}

protected void GenImageStream( ) {
string xaml = GetXaml( );

using (MemoryStream ms = new MemoryStream(xa ml.Length)) {
StreamWriter sw = new StreamWriter(ms );
sw.Write(xaml);
sw.Flush( );
ms.Seek(0, SeekOrigin.Begi n);

Canvas canvas = (Canvas) XamlReader.Load (ms);
canvas.Backgrou nd = Brushes.Yellow;
canvas.Measure( new Size(640d, 480d));
canvas.Arrange( new Rect(0d, 0d, 640d, 480d));
RenderTargetBit map rtb = new RenderTargetBit map(
640, 480, 96d, 96d, PixelFormats.De fault);
rtb.Render(canv as);
JpegBitmapEncod er encoder = new JpegBitmapEncod er( );
encoder.Frames. Add(BitmapFrame .Create(rtb));
using (Stream outstream = new MemoryStream( ))
encoder.Save(ou tstream);
}
}
Oliver Sturm
--
http://www.sturmnet.org/blog - MVP C#

[Jon Davis]

"Willy Denoyette [MVP]" <wi************ *@telenet.bewro te in message
news:70******** *************** ***********@mic rosoft.com...

XAML and WPF is a desktop technology and IMO not designed and not
supported server side, note that the same applies to System.Windows. Forms.

I know. This was a feasibility test.

Jon

[Jon Davis]

"Jon Davis" <jo*@REMOVE.ME. PLEASE.jondavis .netwrote in message
news:%2******** ********@TK2MSF TNGP02.phx.gbl. ..

Oliver,

I'm running your code in a console app now and watching memory consumption
go up in a similar way to IIS. Handle count is frozen solid at 151, but
memory utilization is currently at 271MB at 10000 instances of the loop.
GC.Collect() after the loop completed had no significant effect; took it
to 245MB on second pass.

Jon

OK, I think in conclusion a service that does what I'm considering might
still be feasible but there's some plumbing to be done. If Windows itself
can clear out the memory when the process dies, which it should (haven't
tested), I should be able to use IPC to do this through a Windows Service
that proxies and controls Windows process instances that get reset now and
then (depending on non-use or memory overload). IIS never gets unloaded but
now I'm dealing with parallel "cowboy processes".

Jon