CODEWITHSUNDEEP
c++qtopencv
Poko
Poko

Reputation: 822

Using createButton in opencv2.4.5 (Qt gui features) segfault

I am actually having trouble with the following OpenCV sample:

http://docs.opencv.org/2.4.5/modules/highgui/doc/qt_new_functions.html

(I updated path for my env & added the callbacks functions that are not in the sample).

I compiled Opencv setting Qt On: 


 GUI: 
--     QT 4.x:                      YES (ver 4.8.2 EDITION = OpenSource)
--     QT OpenGL support:           NO
--     OpenGL support:              NO

When I try the code I found in Qt doc: I have the following backtrace:

(gdb) backtrace
#0  0x00007ffff14f53e8 in QAction::setEnabled(bool) () from /usr/lib/x86_64-linux-gnu/libQtGui.so.4
#1  0x00007ffff67bf0db in GuiReceiver::enablePropertiesButtonEachWindow() () from /usr/local/lib/libopencv_highgui.so.2.4
#2  0x00007ffff67c02db in GuiReceiver::addButton(QString, int, int, void*, void*) () from /usr/local/lib/libopencv_highgui.so.2.4
#3  0x00007ffff67c5e9a in GuiReceiver::qt_static_metacall(QObject*, QMetaObject::Call, int, void**) () from /usr/local/lib/libopencv_highgui.so.2.4
#4  0x00007ffff0fcef77 in QMetaMethod::invoke(QObject*, Qt::ConnectionType, QGenericReturnArgument, QGenericArgument, QGenericArgument, QGenericArgument, QGenericArgument, QGenericArgument, QGenericArgument, QGenericArgument, QGenericArgument, QGenericArgument, QGenericArgument) const ()
   from /usr/lib/x86_64-linux-gnu/libQtCore.so.4
#5  0x00007ffff0fd134c in QMetaObject::invokeMethod(QObject*, char const*, Qt::ConnectionType, QGenericReturnArgument, QGenericArgument, QGenericArgument, QGenericArgument, QGenericArgument, QGenericArgument, QGenericArgument, QGenericArgument, QGenericArgument, QGenericArgument, QGenericArgument)
    () from /usr/lib/x86_64-linux-gnu/libQtCore.so.4
#6  0x00007ffff67b23a7 in cvCreateButton () from /usr/local/lib/libopencv_highgui.so.2.4
#7  0x0000000000400f6c in main (argc=, argv=) at main.cpp:20

Does Anyone has the same issue ? I just want to precise that I don't want to embed Opencv in Qt but just use Qt features provided by opencv.

I found a start of answer here: How to use cv::createButton prototype in OpenCV

But this was not relevant...

Thanks for your help.

Still having some problems there is a piece of code:

#include "opencv2/opencv.hpp"
#include "opencv2/highgui/highgui.hpp"

using namespace cv;

void callbackButton(int state, void* userdata){}

int main(int ac, char **av){

     namedWindow("main1",CV_WINDOW_NORMAL);
     namedWindow("main2",CV_WINDOW_AUTOSIZE | CV_GUI_NORMAL);
     int a = 0;

     createButton("test",callbackButton, &a, CV_CHECKBOX,1);
     return 0;
}

Upvotes: 3

Views: 3310

Answers (2)

Wei Hua Chen
Wei Hua Chen

Reputation: 1

I also could not create a button with OpenCV 2.4.5 / Qt 4.8.0. I downloaded OpenCV 2.4.9 and installed it under the same settings, and now it works.

Upvotes: 0

karlphillip
karlphillip

Reputation: 93410

I cannot confirm nor deny that this problem is real since I have a different setup on my machine (OpenCV 2.4.9 and Qt 5.0.2).

But I found that creating a window with CV_GUI_NORMAL crashes the application. The docs states:

CV_GUI_NORMAL or CV_GUI_EXPANDED: CV_GUI_NORMAL is the old way to draw the window without statusbar and toolbar, whereas CV_GUI_EXPANDED is the new enhance GUI.

I suggest you create your windows with CV_GUI_EXPANDED for the time being.

Upvotes: 1

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