Re: Parsing with bison and flex - C / C++ / MFC Discussion Boards

Re: Digital Watermarking - Help/Suggestions Required

l a u r e n20-Jun-03 7:38

20-Jun-03 7:38

essentially watermarking is hiding some known data in a file such that it doesnt degrade the file at all and can be recovered by the right software ... u have to have an algorithm that tells u where to look for the watermark data that obviously u wouldnt want other ppl to find out about or they could change the watermark data and that data must not affect the data of the original file ... images and video are easier but audio can present some problems cos a single wrong data point can cause a click or pop in the playback

it wouldnt matter what language u used for the process of watermarking ... it would depend on what language u were writing the app in

"penguins have no bill"
biz stuff about me

Focus on ComboBox: Problem when pressing "Enter"

Snore20-Jun-03 1:50

Snore

20-Jun-03 1:50

Hello,

I have trouble with my Combo and EditBoxes: If the InputFocus is set to a Combo or EditBox and then the ENTER-Key is pressed, the dialog disappears and in certain cases the application crashes.

How can I catch up those messages, caused by the Enter-Key to avoid this problem?

Best regards

(I have a dialog-based app with MSVC6.00 and MFC)

Re: Focus on ComboBox: Problem when pressing "Enter"

Rage20-Jun-03 2:02

Rage

20-Jun-03 2:02

From Mike's FAQ :

http://www.codeproject.com/cpp/cppforumfaq.asp#mfc_dlgclosekeys[^]

~RaGE();

Parsing with bison and flex

andyg.10120-Jun-03 1:43

andyg.101

20-Jun-03 1:43

Hello I'm interested in coding my own parser for various files using bison and flex. Does anyone know of any good information/tutorials about these tools?
Andy

Re: Parsing with bison and flex

Ryan Binns20-Jun-03 2:05

Ryan Binns

20-Jun-03 2:05

I learnt with "Lex & Yacc" by John Levine, Tony Mason & Doug Brown, by O'Reilly press. It's fairly comprehensive and makes a good reference book, but is simple enough to learn from. There are a couple of substantial examples to explain things (a SQL parser and a menu generation language).

Hope this helps

Ryan

Being little and getting pushed around by big guys all my life I guess I compensate by pushing electrons and holes around. What a bully I am, but I do enjoy making subatomic particles hop at my bidding - Roger Wright (2^nd April 2003, The Lounge)

Punctuality is only a virtue for those who aren't smart enough to think of good excuses for being late - John Nichol "Point Of Impact"

Re: Parsing with bison and flex

andyg.10120-Jun-03 3:33

andyg.101

20-Jun-03 3:33

Ok my next question is where can I get a copy of these programs?
Andy

Re: Parsing with bison and flex

Ryan Binns20-Jun-03 4:01

Ryan Binns

20-Jun-03 4:01

Bison: http://www.gnu.org/software/bison/bison.html[^]

Flex (GNU lex): http://www.gnu.org/software/flex/flex.html[^]

It's for linux, but compiles under Windows (I've done it)

Ryan

Being little and getting pushed around by big guys all my life I guess I compensate by pushing electrons and holes around. What a bully I am, but I do enjoy making subatomic particles hop at my bidding - Roger Wright (2^nd April 2003, The Lounge)

Punctuality is only a virtue for those who aren't smart enough to think of good excuses for being late - John Nichol "Point Of Impact"

Re: Parsing with bison and flex

andyg.10120-Jun-03 4:26

andyg.101

20-Jun-03 4:26

Thanks, my unix is a bit rusty do i need to get make and all that to compile it or can I do it under VisC++?
Smile | :)

Andy

Re: Parsing with bison and flex

Ryan Binns20-Jun-03 4:30

Ryan Binns

20-Jun-03 4:30

VC++ compiles it just fine. If it throws up an error about missing "unistd.h", just create a blank file and put it in your include directory. It's not a necessary file, but it saves from messing with the source Smile | :)

. I can't remember if it asks for it or not. I think that the generated lex or bison C files include it, but it's not necessary and a blank dummy file works fine.

Ryan

Being little and getting pushed around by big guys all my life I guess I compensate by pushing electrons and holes around. What a bully I am, but I do enjoy making subatomic particles hop at my bidding - Roger Wright (2^nd April 2003, The Lounge)

Punctuality is only a virtue for those who aren't smart enough to think of good excuses for being late - John Nichol "Point Of Impact"

In Activex control, child windows are not painted correctly while scrolling IE.

S.Maharajan20-Jun-03 1:41

S.Maharajan

20-Jun-03 1:41

In Activex control designed by MFC wizhard, if we put child windows inside it, while embedding this into IE, in IE scroll, painting child windows is improper. If we invalidate child control either in PosChanged event or paint event, flickering occurs. How to solve this painting problem without any flickering. If any idea, please help me.

Form Problem

Anonymous20-Jun-03 0:43

Anonymous

20-Jun-03 0:43

Hi,
I have to transfer of one formview(MDI) of data to the other formview(MDI). There is no link between these two formview ,only similarity is that both r derived from CFormView.
I am using "file ". In One formview i have "listbox"(which contain data) and transfer of data to the other formview in "editbox".

Thanks

Re: Form Problem

Joan M20-Jun-03 1:15

Joan M

20-Jun-03 1:15

You should use a templated function in your parent's window in order to be able to pass data from one form to the other one.

IE:
PassData(csDestinationWndName, TemplatedDataToPass);

Hope this helps...

detecting exceptions in threads

Chris Eatough20-Jun-03 0:20

Chris Eatough

20-Jun-03 0:20

Hi all,

At the moment my Dialog based program runs 2 threads from inside ...Dlg.cpp. The user interface is updated by the Dialog box, and I am using one for doing all the main functionality, while the other thread prints to a file every minute to let the user know it hasnt crashed. The way it was supposed to work was if the program crashed the printing to the log would stop and a external program would detect this and restart the program. But if(when!) the program throws an exception the dialog saying an exception comes up and the app keeps running its other threads. Wouldnt an unhandled exception stop all the other threads associated with the process, and if not how could i make it do that so i could restart the program?

Thanks

Re: detecting exceptions in threads

Ryan Binns20-Jun-03 2:12

Ryan Binns

20-Jun-03 2:12

Ubersnack wrote:
Wouldnt an unhandled exception stop all the other threads associated with the process

Nope. Exceptions only affect a single thread.

My solution would be to not write to a file at all. I would have the program send a message to the other program (use SendMessage() to the other program's window) periodically, in response to a WM_TIMER message. Do this from the same thread as the one that takes input. If there is an exception, the timer handler will not get called, and the message will not get sent. If the other program doesn't receive a message within a certain time period (I would set it to 2-3 times the message period) then it can restart the program.

Hope this helps,

Ryan

Being little and getting pushed around by big guys all my life I guess I compensate by pushing electrons and holes around. What a bully I am, but I do enjoy making subatomic particles hop at my bidding - Roger Wright (2^nd April 2003, The Lounge)

Punctuality is only a virtue for those who aren't smart enough to think of good excuses for being late - John Nichol "Point Of Impact"

Re: detecting exceptions in threads

Chris Eatough20-Jun-03 3:51

Chris Eatough

20-Jun-03 3:51

cheers mate Big Grin | :-D

Re: detecting exceptions in threads

Jonathan Craig20-Jun-03 3:58

Jonathan Craig

20-Jun-03 3:58

The only way for your program to crash from an exception is from an unhanded exception. Unhanded exceptions are bugs! Make sure you catch your exceptions. When an exception occurs; notify the dialog, stop all threads, and restart the threads. There is not need to have a 2nd application watching and restarting.

If your application requires a complete restart to get things going again, reorganize your code. It needs to be more object oriented.

Hack on! Smile | :)

Jonathan Craig
www.mcw-tech.com

Mouse wheel emulation

Rage20-Jun-03 0:08

Rage

20-Jun-03 0:08

Hi CPians!

I am currently trying to write an app that emulates the mousewheel functionnality. A third part software we often use (a kind of text editor) does not seem to handle mouse wheel messages, so i had the idea to set a hook on mouse messages, to identify the top window, and to send a message to that window.

The problem is, the top window does not respond to my PostMessage or SendMessage. If I use "direct" MFC functions (ShowWindow,ScrollWindow), it works fine, but not when using messages. And the vertical scroll functionnality is only available using a message :

pWndChild->PostMessage(WM_VSCROLL,SB_LINEUP);

has no effect at all.

I've also tried to send WM_KEYUP/KEYDOWN messages (trying to make the app react "as if" the user had hit several times the up or down arrow, or pgup/pgdn), but no way.

My pWndChild which is a CWnd* is alright, because it works fine with functions like ShowWindow,GetWindowText...

Any idea ?

~RaGE();

Re: Mouse wheel emulation

KaЯl20-Jun-03 2:15

KaЯl

20-Jun-03 2:15

The question is, does the top window process WM_xSCROLL messages, or is it done by one of its children (a contained view, for example)? To sum up, are you sure you're sending the messages to the good window? Confused | :confused:

All my life, who am I?

Re: Mouse wheel emulation

Ryan Binns20-Jun-03 2:18

Ryan Binns

20-Jun-03 2:18

Rage wrote:
Any idea ?

Try setting the lParam of the message to the window handle of the window's scrollbar control.

Ryan

Being little and getting pushed around by big guys all my life I guess I compensate by pushing electrons and holes around. What a bully I am, but I do enjoy making subatomic particles hop at my bidding - Roger Wright (2^nd April 2003, The Lounge)

Punctuality is only a virtue for those who aren't smart enough to think of good excuses for being late - John Nichol "Point Of Impact"

Bitmap

Anonymous19-Jun-03 23:34

Anonymous

19-Jun-03 23:34

shrunkenpic is an array with the picture data. It is an unsigned char array with values between 0 and 255
I want to display it
why this code doesn't work. I get only a gray surface not the picture I expect. The picture in the memory ist ok if i display it with setpixel it works and looks fine but this method is to slow
I get about 10-15 pics per second from a cam, so the way to save it first to a bitmap file and then display it is to slow.

CBitmap bild;
bild.CreateBitmap(348, 260, 1, 8, shrunkenPic);
bild.SetBitmapBits(348*260,shrunkenPic);

CDC imageDC;
imageDC.CreateCompatibleDC(pDC);
imageDC.SelectObject( &bild);
pDC->BitBlt(0, 0, 348, 260, &imageDC, 0, 0, SRCCOPY);
imageDC.DeleteDC();

Any Ideas?

Heiko

Re: Bitmap

KaЯl20-Jun-03 2:23

KaЯl

20-Jun-03 2:23

Have you tried something like this?

CBitmap bild;<br />
bild.CreateBitmap(348, 260, 1, 8, shrunkenPic);<br />
bild.SetBitmapBits(348*260,shrunkenPic);<br />
<br />
CImageList imageList;<br />
imageList.Create(348, 260, ILC_COLOR24, 0, 1);<br />
imageList.Add(&bild, (CBitmap *) NULL);<br />
imageList.Draw(pDC, 0, CPoint(0, 0), ILD_NORMAL);

All my life, who am I?

Re: Bitmap

Anonymous20-Jun-03 2:54

Anonymous

20-Jun-03 2:54

unfortunately, the displayed picture is only black
this doesn't work

Ohter Ideas?
I think the failure must be in the CBitmap. Its creation must be buggy.

Re: Bitmap

KaЯl20-Jun-03 3:08

KaЯl

20-Jun-03 3:08

I never used CBitmap::SetBitmapBits, so I can't tell if it works well.
what is your object pDC? A ClientDC?

All my life, who am I?

Re: Bitmap

Anonymous20-Jun-03 11:06

Anonymous

20-Jun-03 11:06

pDC is the DC of the control(picture-control) into which i want to paint the bitmap

CDC *pDC = GetDlgItem(IDC...)->GetDC();

Re: Bitmap

KaЯl20-Jun-03 11:50

KaЯl

20-Jun-03 11:50

I've never use a picture control this way, and I don't know if it is possible to use directly its DC.
Why not using directly a CWnd and catch the WM_PAINT message? At least you would have a total control of the drawing.

All my life, who am I?

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