C / C++ / MFC

Alexander Wiseman19-Jul-04 10:22

19-Jul-04 10:22

Hi,

You might want to check and make sure your hook is properly set up to receive all WM_MOUSEMOVE messages from the target. I'm not sure why you mentioned a timer, because when you have a hook properly installed, the message handler should get called automatically whenever the message comes in.

Take a look at this article: http://www.codeproject.com/atl/MouseGestures.asp[^]. It implements a hook to capture mouse messages as well as then performing calculations on the data stored from the mouse messages.

Hope that helps!

Sincerely,
Alexander Wiseman

Est melior esse quam videri
It is better to be than to seem

User 1278219-Jul-04 10:39

19-Jul-04 10:39

The hook seems to be fine, it catches all the other messages. But it appears, and I think I've read, that a mouse move message doesn't get sent for every fraction the mouse is moved. So I'm wondering how to make it smooth.

modified 12-Jul-20 21:01pm.

bikram singh19-Jul-04 11:11

bikram singh

19-Jul-04 11:11

Why use GetCursorPos() at all, when the lParam of the WM_MOUSEMOVE message provides the same information?

Since Windows isnt an RTOS, you should not use your current tech. Instead, use the pox passed in WM_MOUSEMOVE, which should be good as long as you get enough of the W_MM messages.

Aaron Stubbendieck wrote:
But it appears, and I think I've read, that a mouse move message doesn't get sent for every fraction the mouse is moved

This may be a possibility, since windows is really designed to be functional, more than "perfect". It may have been one of those design trade-offs done to improve things in general...

Bikram Singh

User 1278219-Jul-04 11:46

19-Jul-04 11:46

I just changed it to use the lParam values, and the performance is identical. Its hard to tell from Spy++, but I'm guessing that there isn't a message sent for each movement. I think it can be done, cause apps like VNC product a smooth movement on the client, and I just want to do that locally. I've looked at the vnc source code and can't find anything magic that they did.

modified 12-Jul-20 21:01pm.

bikram singh19-Jul-04 12:31

bikram singh

19-Jul-04 12:31

Jumpy cos no data, possible.

This is interesting, needless to say, i will try this in the next couple of days.

What is VNC? And if you have the sources for it, and it works as you desire, could i see some of it?

Bikram Singh

User 1278219-Jul-04 13:24

19-Jul-04 13:24

That'd be nice if you could take a look at it.

VNC stands for Virtual Network Computing and allows you control and see the screen of a remote computer. You can get the sources here[^]. When a remote user moves the mouse, the movement is smoothly reproduced on the host machine. The code in the server that set the cursor pos doesn't seem any more sophisticated than SetCursorPos.

modified 12-Jul-20 21:01pm.

Alexander Wiseman19-Jul-04 15:47

19-Jul-04 15:47

I tried to quickly implement a basic dialog-based application which recorded mouse movement for about 2 seconds and then replayed the result. Oddly enough, the movement was smooth and exactly what I did during the recording period. Granted this wasn't through hooking, but I think it proves that one should be able to get every mouse movement, or at least a sufficient number to reproduce a smooth motion.

Here is the main code for recording and replaying ('points' is a CArray of CPoints and 'pt' is a CPoint, both defined in the class definition):

<br />
void CMouseMoveDlg::OnMouseMove(UINT nFlags, CPoint point) <br />
{<br />
	if(bStarted)<br />
	{<br />
		GetCursorPos(&pt);<br />
		points.Add(pt);<br />
	}<br />
	<br />
	CDialog::OnMouseMove(nFlags, point);<br />
}<br />
<br />
void CMouseMoveDlg::OnReplay() <br />
{<br />
	for(int h = 0; h < points.GetSize(); h++)<br />
	{<br />
		pt = points.GetAt(h);<br />
		SetCursorPos(pt.x, pt.y);<br />
		Sleep(10);<br />
	}<br />
}<br />

If you would like I could have a look at your code. If you wish to send it to me (or just the relevant portions) my email address is Alexander@wisemanweb.com. I will try to implement this logic inside a hook as soon as I have a chance.

Sincerely,
Alexander Wiseman

Est melior esse quam videri
It is better to be than to seem

Alexander Wiseman19-Jul-04 15:56

19-Jul-04 15:56

Okay wow. I was just sitting here, reading MY OWN CODE, and something hit me. Did you actually check the data stored in your data structure to see whether all of it was there, or were you just going by what it looked like? If you look at my post immediately before this, I added a call to the Sleep function in order to give a little bit of spacing between the SetCursorPos() calls. It could be that all of the data is there but you don't see smooth mouse movement because you are calling SetCursorPos too quickly. Try adding something like Sleep(10) and see if the motion is smooth. If that doesn't work, check your data structure (print it to the screen or something) and check the results against a Spy++ on the Window.

If all else fails, I can look at your code if you would care to send it to me.

Sincerely,
Alexander Wiseman

Est melior esse quam videri
It is better to be than to seem

User 1278220-Jul-04 11:28

20-Jul-04 11:28

Wow! that was it! Just adding a Sleep(1) call after every SetCursorPos call, made it work just fine. I guess all it needed was a moment to draw it.

Thanks!!

modified 12-Jul-20 21:01pm.

Alexander Wiseman20-Jul-04 11:34

20-Jul-04 11:34

Cool! Glad I could help. Smile | :)

Sincerely,
Alexander Wiseman

Est melior esse quam videri
It is better to be than to seem

gamitech19-Jul-04 12:03

gamitech

19-Jul-04 12:03

try using some sleeps
or threads

gabby

User 1278219-Jul-04 12:24

19-Jul-04 12:24

I believe its jumpy because there isn't enough data.

modified 12-Jul-20 21:01pm.

Database Application Performance

gamitech19-Jul-04 13:11

gamitech

19-Jul-04 13:11

mmm
i think you're right

gabby

Threading...

0v3rloader19-Jul-04 7:37

0v3rloader

19-Jul-04 7:37

Hello,

This time the question if about threading... hope you'll appreciate it.

Well then, I have a worker thread being created at some point in my App. It happens that this [new] thread creates about 5 modeless dialogs which continuously output data. This thread was derived from CWinThread; Everything fine so far...

Now, this is where it gets tricky: inside the InitInstance I initialise a class, which has no links whatsoever to a message pump nor to the main frame window. Moreover, it has to execute in a kind of a loop. Here's an example:

BOOL CClass::InitInstance()
{
	CG1	theG1;

	// init dialogs
	// init controls, etc

	theG1.Run();		// lets make the emulator run the program then
	
	// it exited...
	// de-init everything
	return FALSE;
}

This was my first (frustrated) attempt and I quickly learned that whenever the instruction execution reached inside theG1.Run, there were no Windows Messages being received/processed.

So I made some changes. Instead of having it run inside InitInstance, I implemented a solution with OnIdle. I don't really like it, but let's see how I did it:

CClass::OnIdle(long nCount)
{
	// execute the next instruction
	theG1.ExecuteNext();	// had to decompose <code>Run</code> into ExecuteNext()
	// lets return and ask for more
	// processing time
	return TRUE;
}

Now my question:

Is is possible to make the class run in a real multi-threading environment rather than in OnIdle? I know I would have to somehow make a connection with the thread's Message Pump... but how?

Any suggestions would be greatly appreciated,

David

PS: In case you got confused with the methods I'm using above (Run; ExecuteNext) , I am working on an academic project aimed at emulating a processor on a x86 machine.

Re: Threading...

David Crow19-Jul-04 9:17

David Crow

19-Jul-04 9:17

dNimrod#X wrote:
I have a worker thread being created at some point in my App. It happens that this [new] thread creates about 5 modeless dialogs...

This raises a lot of red flags, namely that worker threads should not create UI components. If you must create a UI component in a thread other than the primary thread, it should be a UI thread (i.e., thread with a message pump). See here for more.

"When I was born I was so surprised that I didn't talk for a year and a half." - Gracie Allen

Re: Threading...

0v3rloader19-Jul-04 22:53

0v3rloader

19-Jul-04 22:53

Hi,

I've been reading on the subject and decided to follow your cue. You're absolutely right -- there is the need to have a message pump thread.

Thanks very much for the reply. You have been very helpful indeed.

David

Sridhar Sanikommu19-Jul-04 7:01

Sridhar Sanikommu

19-Jul-04 7:01

Hi,

I'm developing a database application using CDatabase & CRecordSet classes. My SQL Server database
is sitting on other machine and it's effecting application performance when I tried to insert large number of records
and retrieving the records for generating some reports(i.e. to fetch 1000000 records at a time for creating a report). Application is getting too slow.

Need some suggestions in this regard.

Thanks,

G. Steudtel19-Jul-04 7:10

G. Steudtel

19-Jul-04 7:10

Hi,
probably instead of using mysql_store_result you should using mysql_use_result. It will give you a boost, but also a lot of drawbacks. See the C-API documentation for that.

GSte

Ivan Cachicatari19-Jul-04 7:12

Ivan Cachicatari

19-Jul-04 7:12

Hi,

I recommend to segment this query or install more physics memory.

navisoft
www.latindevelopers.com

Alexander Wiseman19-Jul-04 7:25

19-Jul-04 7:25

How are you using CRecordset? Are you predefining the query and the columns it returns with CRecordset, or are you simply creating a CRecordset from a query at run-time? If you are doing the former (predefining the query and the columns), there are some operations in which CRecordset performs very inefficient methods on the data, and it could be that the slowness you are seeing is because CRecordset is clogging the system memory.

Check which way you are using CRecordset and also pull up Task Manager while your long query is running to see how much system memory it is sucking up.

Sincerely,
Alexander Wiseman

Est melior esse quam videri
It is better to be than to seem

Sridhar Sanikommu19-Jul-04 7:35

Sridhar Sanikommu

19-Jul-04 7:35

Hi,

I'm using the former one. I have to read a text file which has more than million records and insert each record at a time. Also, for genearting some reports, i've to fetch huge number of records at a time from the database and process all the records.

Thanx,

Alexander Wiseman19-Jul-04 10:14

19-Jul-04 10:14

So, just to clarify exactly what you are trying to do: you are opening and reading a text file from which data you want to insert records into a database. Because you want to insert so many records, I would suggest using a SQL command to insert the data (INSERT INTO...) instead of CRecordset::AddNew() and CRecordsSet::Update(). The CRecordset functions for adding records tend to be slower than simply executing a SQL statement against the database. You can execute a SQL statement by using the function in CDatabase (I forget the exact name, but it is something like "Execute").

For fetching large numbers of records, I would also suggest that you move away from the default RFX (Recordset Field Exchange - where you predefine the columns returned from the query) implemented with CRecordset. Again, this tends to be slower than simple qeurying the database with SQL statement and not using RFX. For some more information on this topic, take a look at the ODBC section on CodeProject: http://www.codeproject.com/database/#ODBC[^].

If you need more specific information, or some example code, please let me know.

Sincerely,
Alexander Wiseman

Est melior esse quam videri
It is better to be than to seem

Sridhar Sanikommu19-Jul-04 11:28

Sridhar Sanikommu

19-Jul-04 11:28

Hi Alexander,

Thanks for your input. Right now, I'm not using RFX for fetching the records nor
AddNew() and Update() functions of CRecordset classes. As you said, i'm reading each record from the text file and create INSERT INTO.. query and execute it using CDatabase
ExecuteSQL() function. However, for every call to this function, database has to parse , prepare an execution plan and compile it. Instead i'm thinking of using stored procedures. But my application has to support multipe databases like MSAccess, MySQl, Oracle & MS SQL Server. I don't think MSAccess supports Stored procedures and I'm not sure of MySQL either.

Do you have any generic database module? If so, can you send it to me?

I would appreciate your help.

Thanx,

Alexander Wiseman19-Jul-04 15:52