display a plot point by point

[wysota]

I suggest you improve your C++ skills a bit before taking on Qt.

[oswalidos]

hello ,
i realized that my problem have no relation with my code.
in fact a simple application like "simple_plot" works normally when i create a new project ,move sources and modify *.pro ,but when i do the same for other example like "real_time plot" and try to build it , i have the same problem with a warning(exited with code -1073741819 ,no errors ,warning: #warning better use QwtData) and degugger don't works anymore .
so it's a configuration problem .
i downloaded qwt 5.2 from svn but it's the same problem !

-each time i want to run my application from Qt console or from Qt creator i have to add qwtd5.dll to debug folder,everybody do that ?
-i want to buid Qt in debug mode ,it takes time ,finally it generate errors related with visual studio 2008
-why to build Qt in debug mode?
-mingw's gdb isn't enough to debug Qt applications since we're using Qt's sources ?
-what about .pri and .prf ? should i modify one ?
-why debugger under Qt creator works(just for an application without macro Q_OBJECT) even if Qt isn't buit in debug mode ?

please look up my .pro
if my questions proves that i'm lost ,some links will be enough to stop annoying you .

regards

[oswalidos]

sorry ,my problem have no relation with c++ ,i didn't separate my files to .h and .cpp simply cuz i'm still testing qwt(that what makes you think i need to improve my c++ skills?) .
i'm sure my c++'s skills allows me to use Qt,it doesn't need a c++ expert !
anyway thanks for your help and advices .

[oswalidos]

my .pro for the real_time_plot :

TARGET = QDSQ
TEMPLATE = app
DEPENDPATH += .
INCLUDEPATH += C:\Qwt-5.2.0-svn\include
LIBS += C:\Qwt-5.2.0-svn\lib\qwtd5.dll
CONFIG +=debug
 
HEADERS += scrollzoomer.h \
    scrollbar.h \
    randomplot.h \
    mainwindow.h \
    incrementalplot.h
SOURCES += scrollzoomer.cpp \
    scrollbar.cpp \
    realtime.cpp \
    randomplot.cpp \
    mainwindow.cpp \
    incrementalplot.cpp
 
OTHER_FILES += start.xpm \
    clear.xp

TARGET = QDSQ
TEMPLATE = app
DEPENDPATH += .
INCLUDEPATH += C:\Qwt-5.2.0-svn\include
LIBS += C:\Qwt-5.2.0-svn\lib\qwtd5.dll
CONFIG +=debug

HEADERS += scrollzoomer.h \
    scrollbar.h \
    randomplot.h \
    mainwindow.h \
    incrementalplot.h
SOURCES += scrollzoomer.cpp \
    scrollbar.cpp \
    realtime.cpp \
    randomplot.cpp \
    mainwindow.cpp \
    incrementalplot.cpp

OTHER_FILES += start.xpm \
    clear.xp

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[wysota]

-each time i want to run my application from Qt console or from Qt creator i have to add qwtd5.dll to debug folder,everybody do that ?

No, you can place the library in any place the dynamic linker will be looking for it. The directory where the application binary resides is one of those places but not the only one.

-why to build Qt in debug mode?

So that you can peek inside internal Qt library calls.

-mingw's gdb isn't enough to debug Qt applications since we're using Qt's sources ?

Yes, it is. But it won't tell you much without debugging symbols. Such an experienced C++ programmer as yourself should know that

-what about .pri and .prf ? should i modify one ?

What for?

-why debugger under Qt creator works(just for an application without macro Q_OBJECT) even if Qt isn't buit in debug mode ?

See the answer above.

[oswalidos]

No, you can place the library in any place the dynamic linker will be looking for it. The directory where the application binary resides is one of those places but not the only one.

but if i move dll to other directory,i can't run executable ,error :exited with code -1073741819 .

anyway,my problem is how to buid any application with no error ,the code of real_time_plot must work with no error !

so could you tell me if there is a problem with my .pro ?
i found here :

If you are working with a DLL on Windows you also have to add:

DEFINES += QWT_DLL

The Qwt tarball also includes a qwt.prf file. When you have adjusted and installed it, it does the configurations lines above for you and you can simply write:

CONFIG += qwt

i can't do like he said , i can't got what he mean :
-if you're working with dll
- qwt tarball
-qwt.prf

thanks for your help

[wysota]

but if i move dll to other directory,i can't run executable ,error :exited with code -1073741819 .

The application probably picks up another version of the library that resides somewhere in your system.

anyway,my problem is how to buid any application with no error ,the code of real_time_plot must work with no error !

Your application builds without error. It just doesn't run. That's two different things.

so could you tell me if there is a problem with my .pro ?

No, your pro is fine.

i can't do like he said , i can't got what he mean :
-if you're working with dll
- qwt tarball
-qwt.prf

What do you mean you can't do it?

[oswalidos]

i installed Qt 4.4 and 4.5 and qwt 5.1.1 and 5.3 and 5.2 and visual studio 2008 and 2 or 3 mingw ,so my environnement can get confused ?

What do you mean you can't do it?

i don't have :
DEFINES += QWT_DLL
CONFIG += qwt
in my pro ,i can't do that cuz i don't understand why should i do that , in addition i tried but it makes other problems

thanks again

[wysota]

i don't have :
DEFINES += QWT_DLL
CONFIG += qwt
in my pro ,i can't do that cuz i don't understand why should i do that , in addition i tried but it makes other problems

If the guy tells you to do it, then do it. If you have problems, it means you have to solve them. Those statements initialize the use of Qwt in your application.

I suggest you uninstall everything and start from scratch slowly, without shooting blind. Install one development environment and one Qt version. Then install one version of Qwt (follow the install guide that comes with Qwt), add what's needed to your project file and then start developing software based on Qwt.

[oswalidos]

ok ,i'll restart everything ,by the way the guy didn't tell me,i found it somewhere
thanks for your help

[oswalidos]

hi again ,
i restart everything and my news :
-able to debug my application with visual c++ debugger (given with Qt creator)
-i downlaod mingw while i'm installing Qt 4.5 .
-is it normal to don't use the mingw debugger ? (anyway it works)
-i still have to copy qwtd5.dll to debug folder of my application ,otherwise with debugging i got a runtime error ! (can you help me for that ?)
-i can back now to my problem : displaying point by point a curve .

now the code i posted works with no error but the curve don't appear point by point ,first time no curve ,after some seconds i have to refresh the window to see the curve .

i think if Qt run only one thread(i can see that in debugger) for my application i can't get what want ,i may should create a thread for the methode which call timer ,to get two parellel threads ,one to show the window and second takes care of the timer and giving data .

am i right?

thanks for your help

[wysota]

No, you are wrong. See the attachment.

About the DLL - place it in your Windows\System32 folder or along other Qt DLL files.

[oswalidos]

it was a nice conversation
coping my dll under system32 solve the problem.
about code i have just to put replot(); in the right places and it works :

void Plot::onTimeout(){             //each timeout data will
  currentPointPosition++;           // be added to the curve
  if(currentPointPosition>1000) currentPointPosition = 1;
  curve->setData(x, y, currentPointPosition);
  replot();
}
 
void Plot::pointByPoint(){ //calling this method provoque painting curve "slowly"
    for(int i=0;i<1000;i++){
        timer->start(10);
    }
}
 
//in constructor
   connect(timer, SIGNAL(timeout()), this, SLOT(onTimeout()));
   // add curves
   curve = new QwtPlotCurve("Vitesse");
   curve->setPen(QPen(Qt::green));
   curve->attach(this);
   currentPointPosition=1;
   curve->setData(x, y, currentPointPosition);
   replot();

void Plot::onTimeout(){             //each timeout data will
  currentPointPosition++;           // be added to the curve
  if(currentPointPosition>1000) currentPointPosition = 1;
  curve->setData(x, y, currentPointPosition);
  replot();
}

void Plot::pointByPoint(){ //calling this method provoque painting curve "slowly"
    for(int i=0;i<1000;i++){
        timer->start(10);
    }
}

//in constructor
   connect(timer, SIGNAL(timeout()), this, SLOT(onTimeout()));
   // add curves
   curve = new QwtPlotCurve("Vitesse");
   curve->setPen(QPen(Qt::green));
   curve->attach(this);
   currentPointPosition=1;
   curve->setData(x, y, currentPointPosition);
   replot();

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think you so much for your help
how to mark this thread as solved ?