.NET (Core and Framework)

27-Sep-05 9:23

Hi folks,
The following piece of C#.NET code creates an A4 size binary image by reading values from a two-dimensional byte array iPage[][].
Is there anyway I can further optimize the nested for loop inside the unsafe block? It is taking ~2.2s, and I'd love to bring it down further.
Sarab.

// page dimensions
iwd=iPage.Length;
iht=iPage[0].Length;

// create new bitmap
bMap=new Bitmap(iwd, iht, PixelFormat.Format24bppRgb);

// create bitmap data
bData=bMap.LockBits(new Rectangle (0,0,iwd,iht),ImageLockMode.WriteOnly,PixelFormat.Format24bppRgb);

// get bitmap position
Scan0 = bData.Scan0;
iStride=bData.Stride;

unsafe
{
// initialize pointer
byte *p = (byte*)(void*)Scan0;
int nOffset = iStride-iwd*3;

for(int y=0;y<iht;++y)
{
for(int x=0;x<iwd;++x)
{
if (iPage[x][y]==0) p[0]=p[1]=p[2]=255;
else p[0]=p[1]=p[2]=0;
p += 3;
}
p += nOffset;
}
}

PS. the code above is inspired from the article(s): http://www.codeproject.com/cs/media/csharpgraphicfilters11.asp

Dave Kreskowiak27-Sep-05 12:01

Dave Kreskowiak

27-Sep-05 12:01

It looks like that about as fast as your going to get it without resorting to writing the thing in Managed C++.

Whoops! Accidently clicked Submit...

If you can come up with an algorithm to get rid of that if statement, you'll probably cut the time in half.

RageInTheMachine9532
"...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome

-- modified at 18:01 Tuesday 27th September, 2005

sarabjs28-Sep-05 11:26

28-Sep-05 11:26

hmm... not so confident in managed c++.. can't remove the if statement either!
thanks anyways...

Daniel Grunwald30-Sep-05 22:56

Daniel Grunwald

30-Sep-05 22:56

What values does the byte array contain? Do you only swap 0 <-> 255 or does the byte array contain different values?
When it contains only 0 or 255, you can use p[0]=p[1]=p[2]=~iPage[x][y];
How do you create the iPage array? If you could swap it to be iPage[y][x], you could evaluate iPage[y] outside the inner loop. (byte[] thisRow = iPage[y] and then continue to use the inner loop).
Also, you might want to eliminate bounds checking on iPage array access by using a foreach loop (it looks slower, but the C# compiler generates special code (no bounds checking) when foreach is used on an array).
So propably this could be faster: (provided you swap x and y in your array creation and use only the values 0 and 255):
foreach (byte[] row in iPage) {
foreach (byte val in row) [
p[0] = p[1] = p[2] = ~val;
p += 3;
}
p += nOffset;
}

sarabjs3-Oct-05 6:30

3-Oct-05 6:30

Thanks Daniel!
Redefining my array as iPage[y][x] and using the foreach loop worked wonders! The execution time's safely within the acceptable range now Smile | :)

Thanks !!!

.NET locking DLLs

Gilad Kapelushnik26-Sep-05 23:48

Gilad Kapelushnik

26-Sep-05 23:48

Hi
I'm working on a solution containing 10-15 projects that generate DLLs.
Some projects use DLLs generated by other projects, I solve this by setting dependcies...
All DLLs are generated in one location.
No local copies are made when building the DLLs

For some reason, .NET hangs on to some of the DLL files (the .NET process) thus dening me from replacing them with new ones. From the 10-15 projects there are 2-3 DLLs being held as "open", even if no build\debug in process.

I solve this by exiting .NET, deleteing the DLLs and rebuilding them.

Any solution ?

Gilad.

drawing text on an image

sarabjs26-Sep-05 5:30

Re: drawing text on an image

26-Sep-05 5:30

Hello folks,

I wish to write text on an Image in .NET

I figure I can use the Graphics.drawString() method to do so, but it turns out that .NET would only allow me to write on images with non-indexed pixel formats.

The format I'm now using is 1bppIndexed, which allows me to keep the size of these image objects limited. I do not wish to change these images to a non-indexed pixel format like 24bppRGB (even though that allows me to draw text on the image), 'cause here I'm only dealing with binary images, each around 3500pixels by 2480pixels.

Since a format like 24bppRGB occupies much more space than what is required, I was hoping there would be a way to write on the 1bppIndexed images directly.

Any ideas?

Thanks...

Guido_d26-Sep-05 23:18

Guido_d

26-Sep-05 23:18

If you're using 1bpp images, that's plain black and white. Truetype fonts require more color depth to perform antialiasing, so that won't work. You can go three ways IMO:
- render the font to a transparent image, convert to black & white and overlay over the original image, possibly creating a jagged font
or
- convert the image to more bpp, then render the text on top of it, then convert back to b&w. Will use a lot of memory for the converted image.
or
- use a bitmapped font that you can directly add to the image by using SetPixel()

Good luck..

Re: drawing text on an image

Guido_d26-Sep-05 23:34

Guido_d

26-Sep-05 23:34

Oops I overlooked the 1bpp INDEXED, so not black & white, but the same solutions apply IMO.

Re: drawing text on an image

sarabjs27-Sep-05 8:50

Strange behaviour with a System.Net.Sockets.Socket

27-Sep-05 8:50

Understood the anti-aliasing part..
But didn't quite understand your first suggestion..
As for your second suggestion, I figure it doesn't solve the memory problem..
Guess will take a shot at attempting your third suggestion though...
Thanks...

Sarab

Guido_d26-Sep-05 3:53

Guido_d

26-Sep-05 3:53

Hi,

Strange behaviour with a System.Net.Sockets.Socket, reproducable on 95, 2000
and XP

If I reuse a socket object after initializing it I can reconnect without
problems.

But

If the application has been running for 23 minutes or longer, the socket
will forever
wait for BeginConnect() to finish. Confused | :confused:

If I use a Connect() (also after 23 minutes) instead of async connecting the call will block
forever. OMG | :OMG:

I am using the following (pseudo) code to test. If running this after 23
minutes, the connect fails
and it is impossible to reconnect without restarting the application.

Is this known behaviour? Is there a workaround? Am I making a mistake? Help would be greatly
appreciated. For the time being I dropped a winsock control on a form and use that as my async socket.

regards

Guido

this is the offending code:

<br />
class SocketConnector<br />
{<br />
 AsyncCallback m_callback = null;<br />
 System.Net.Sockets.Socket m_socket = null;<br />
 bool m_connected = false;<br />
 public bool Connected<br />
 {<br />
  get { return m_connected; }<br />
 }<br />
 public void Connect(string ipaddress, int port)<br />
 {<br />
  // set up callback<br />
  m_callback = new AsyncCallback( OnConnect );<br />
<br />
  // create socket<br />
  m_socket = new Socket (AddressFamily.InterNetwork,SocketType.Stream <br />
,ProtocolType.Tcp );<br />
  m_socket.Blocking = false;<br />
<br />
  // get the remote IP address<br />
  IPAddress ip = IPAddress.Parse (ipaddress);<br />
  int iPortNo = System.Convert.ToInt16 ( port);<br />
<br />
  //create the end point<br />
  IPEndPoint ipEnd = new IPEndPoint (ip,iPortNo);<br />
<br />
  // begin async connect<br />
  IAsyncResult ar = m_socket.BeginConnect( ipEnd, m_callback, m_socket );<br />
<br />
  // wait for connect<br />
  ar.AsyncWaitHandle.WaitOne(2000,false);<br />
<br />
  if (!ar.IsCompleted || m_callback!=null)<br />
  {<br />
   // BeginConnect did not finish, breakpoint here to test<br />
   m_connected = false;<br />
   // ..<br />
   return;<br />
  }<br />
  // beginconnect finished OK<br />
  m_connected = true;<br />
 }<br />
 void OnConnect(IAsyncResult result)<br />
 {<br />
  m_callback = null;<br />
 }<br />
} <br />
<br />

What API can be used to access MS Project?

kurdi1926-Sep-05 3:14

kurdi19

26-Sep-05 3:14

What API can be used to extract data from MS Project with?

Thanks...

XmlSerializer question

Ivanets26-Sep-05 1:13

Ivanets

26-Sep-05 1:13

Hi All!

I use XmlSerializer to serialize object and got the following:

<?xml version=\"1.0\" encoding=\"utf-16\"?>
<MyClass xmlns:xsd=\"http://www.w3.org/2001/XMLSchema\" xmlns:xsi=\"http://www.w3.org/2001/XMLSchema-instance\" xmlns=\"http://www.MyFirma.biz/MyNamespace\">
<Positions>
<Position>
</Position>
...
</Positions>
</MyClass>

Is it possible to get rid of the overhead (namespace info, schema info, xml version)? Anyway I do not need this info since parsing will be done without XmlSerializer.

So I need that output looks like below:

<MyClass>
<Positions>
<Position>
</Position>
...
</Positions>
</MyClass>

Thanks!

Find RichTextBox BackColor in VB.NET

lupus canus25-Sep-05 23:56

lupus canus

25-Sep-05 23:56

Hi,

how can I find Text with specific BackColor in my RTB and replace it with another BackColor ? I do not know the Text, Startposition, Length and number of the text pieces with the specific BackColor.

Thanks

Lupus

Re: Find RichTextBox BackColor in VB.NET

lupus canus26-Sep-05 7:12

lupus canus

26-Sep-05 7:12

Sorry,

I put my question in the wrong section of this forum.

I'll repeat my question in the section "Visual Basic / VB.NET"

Lupus

IL and MSIL

Rajesh_K_Sharma25-Sep-05 20:12

Rajesh_K_Sharma

25-Sep-05 20:12

What is difference between IL and MSIL in Dot.net FrameWork.
Regards
Rajesh

rajesh

Re: IL and MSIL

Saqib Shakil25-Sep-05 21:28

Saqib Shakil

25-Sep-05 21:28

As much as I know both are the same in dot net
where as IL is a more generic term Java Byte Code is an IL
any code that runs in some kind of a virtual environment is an IL

Regards,
Saqib Shakil

Re: IL and MSIL

Dave Kreskowiak26-Sep-05 3:09

Dave Kreskowiak

26-Sep-05 3:09

In the .NET Framework, IL is MSIL. It's Microsoft Intermediate Language.

RageInTheMachine9532
"...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome

information regarding stack trace

ravibabu_kanaparthi25-Sep-05 19:20

ravibabu_kanaparthi

25-Sep-05 19:20

HI all,

I need some information regarding stack trace of the .net framework.

As we know,when ever an exception occurs some details will be shown in the stack trace.
In my project we have a system to lock the exact exception occured ..
using like this
Exception e;
e.InnerMessage;

I am using exception handling (try,catch,finally) in my development.

These details will be stored in some error log folder as files per each day.

My request is ...
1.)In which are the situations we will use stack trace related details in coding.
2.)Can i use the stack trace details for my project scenario more effectively than the existing system. If so pls give me details how can use that.

Thanks in advance,
Deepu

.Net Application not Runing on Test System

Zishan Haider25-Sep-05 4:19

Zishan Haider

25-Sep-05 4:19

I have intalled .Net Framework 1.1 With SP1 on my test PC which is Running on Windows XP Home Edition and Windows 2000 Professional. My app crashes with some unknown Exception. I have tried a simple Windows App with just a few default controls it still doesnt work.

Error Shows

Common Language Runtime Debugging Services
Application Has Generated an exception that could not be handled

ProcessID = 0x128(288) ThreadID= 0x546(???)

What could be wrong with it

I have tried Both debug and release versions

Zishan Haider

Steve Pullan25-Sep-05 14:17

Steve Pullan

25-Sep-05 14:17

You mention both XP and 2000 on your machine. Are you sure that the .NET framework is installed on the one you are using for the tests? If not, it will fail.

Another possibility is that the assembly is not running under the proper security credentials (e.g. running from a network drive without sufficient trust set for the intranet zone).

...Steve

Anonymous25-Sep-05 17:48

Anonymous

25-Sep-05 17:48

The test systems did not have .net framework installed prevously. I installed it by running that 23MB framework file only. I even installed the SP1 after the framework installtion. And no.. The test system is isolated, i.e. not connected through any network. I am running it through the local hard drive. What else can be wrong?

Regards...

Steve Pullan25-Sep-05 20:28

Steve Pullan

25-Sep-05 20:28

The framework is not correctly installed or you are targetting the wrong version of the framework in your assembly.

...Steve