Mixing
Qt5 and OpenCv 4
1
I want to use the OpenCv framework with Qt Applications on Linux (Debian). From https://opencv.org/releases.html I've downloaded the opencv-4.0.1.zip and unzip it into a folder. Then using CMake GUI I've configured the build with BUILD_opencv_world option marked. Then I generate the build and with compiled the library with make and make install and everything seems to be fine.
I've created a opencv.pri file with:
INCLUDE += /usr/local/include
LIBS += -L/usr/local/lib -lopencv_world
To test OpenCv I've created a Qt command line project and try to load an image and display, here the QtCvTest.pro
QT -= gui
CONFIG += c++11 console
CONFIG -= app_bundle
# The following define makes your compiler emit warnings if you use
# any feature of Qt which as been marked deprecated (the exact warnings
# depend on your compiler). Please consult the documentation of the
# deprecated API in order to know how to port your code away from it.
DEFINES += QT_DEPRECATED_WARNINGS
# You can also make your code fail to compile if you use deprecated APIs.
# In order to do so, uncomment the following line.
# You can also select to disable deprecated APIs only up to a certain version of Qt.
#DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x060000 # disables all the APIs deprecated before Qt 6.0.0
SOURCES += main.cpp
include(/home/stefano/opencv-4.0.1/opencv.pri)
and main.cpp
#include <QCoreApplication>
#include <QDebug>
#include <opencv2/opencv.hpp>
int main(int argc, char *argv)
{
QCoreApplication a(argc, argv);
qDebug() << "QtCvTest Start";
using namespace cv;
Mat image;
image = imread("/home/stefano/Pictures/2018/02/27/DSC_1421.JPG", CV_LOAD_IMAGE_COLOR);
if(! image.data ) {
qDebug() << "Could not open or find the image";
return -1;
}
namedWindow( "Test", WINDOW_AUTOSIZE );
imshow( "Test", image );
qDebug() << "QtCvTest End";
return a.exec();
}
If I try to compile I get the following error
main.cpp:22: error: undefined reference to `cv::_InputArray::_InputArray(cv::Mat const&)'
any idea how to solve this error?
Thanks in advance for your help
c++ qt opencv
asked Jan 1 at 20:19
StefanoStefano
438
|
show 4 more comments
1
I want to use the OpenCv framework with Qt Applications on Linux (Debian). From https://opencv.org/releases.html I've downloaded the opencv-4.0.1.zip and unzip it into a folder. Then using CMake GUI I've configured the build with BUILD_opencv_world option marked. Then I generate the build and with compiled the library with make and make install and everything seems to be fine.
I've created a opencv.pri file with:
INCLUDE += /usr/local/include
LIBS += -L/usr/local/lib -lopencv_world
To test OpenCv I've created a Qt command line project and try to load an image and display, here the QtCvTest.pro
QT -= gui
CONFIG += c++11 console
CONFIG -= app_bundle
# The following define makes your compiler emit warnings if you use
# any feature of Qt which as been marked deprecated (the exact warnings
# depend on your compiler). Please consult the documentation of the
# deprecated API in order to know how to port your code away from it.
DEFINES += QT_DEPRECATED_WARNINGS
# You can also make your code fail to compile if you use deprecated APIs.
# In order to do so, uncomment the following line.
# You can also select to disable deprecated APIs only up to a certain version of Qt.
#DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x060000 # disables all the APIs deprecated before Qt 6.0.0
SOURCES += main.cpp
include(/home/stefano/opencv-4.0.1/opencv.pri)
and main.cpp
#include <QCoreApplication>
#include <QDebug>
#include <opencv2/opencv.hpp>
int main(int argc, char *argv)
{
QCoreApplication a(argc, argv);
qDebug() << "QtCvTest Start";
using namespace cv;
Mat image;
image = imread("/home/stefano/Pictures/2018/02/27/DSC_1421.JPG", CV_LOAD_IMAGE_COLOR);
if(! image.data ) {
qDebug() << "Could not open or find the image";
return -1;
}
namedWindow( "Test", WINDOW_AUTOSIZE );
imshow( "Test", image );
qDebug() << "QtCvTest End";
return a.exec();
}
If I try to compile I get the following error
main.cpp:22: error: undefined reference to `cv::_InputArray::_InputArray(cv::Mat const&)'
any idea how to solve this error?
Thanks in advance for your help
c++ qt opencv
asked Jan 1 at 20:19
StefanoStefano
438
1
changeINCLUDEtoINCLUDEPATH, change-lopencv_worldto-lopencv_imgproc -lopencv_core -lopencv_highgui -lopencv_imgcodecs
– eyllanesc
Jan 1 at 20:49
Or use:CONFIG += link_pkgconfigPKGCONFIG += opencv4
– eyllanesc
Jan 1 at 20:49
Now it works! I've changed toINCLUDEPATHand added the link to opencv_imgproc, opencv_core and opencv_highgui. If I add also opencv_imgcodecs I get an error (-1: error: cannot find -lopencv_imgcodecs). Thanks a lot for your help!
– Stefano
Jan 1 at 22:32
It seems that when you compiled you did not disable a flag that compiles that binary, it does not matter
– eyllanesc
Jan 1 at 22:34
1
with PKGCONFIG + = opencv you are adding all the -l{libs} so your executable is probably very heavy unlike if you add one by one as in the first case so for development use PKGCONFIG and for production I only link the necessary ones.
– eyllanesc
Jan 1 at 22:41
|
show 4 more comments
1
1
1
I want to use the OpenCv framework with Qt Applications on Linux (Debian). From https://opencv.org/releases.html I've downloaded the opencv-4.0.1.zip and unzip it into a folder. Then using CMake GUI I've configured the build with BUILD_opencv_world option marked. Then I generate the build and with compiled the library with make and make install and everything seems to be fine.
I've created a opencv.pri file with:
INCLUDE += /usr/local/include
LIBS += -L/usr/local/lib -lopencv_world
To test OpenCv I've created a Qt command line project and try to load an image and display, here the QtCvTest.pro
QT -= gui
CONFIG += c++11 console
CONFIG -= app_bundle
# The following define makes your compiler emit warnings if you use
# any feature of Qt which as been marked deprecated (the exact warnings
# depend on your compiler). Please consult the documentation of the
# deprecated API in order to know how to port your code away from it.
DEFINES += QT_DEPRECATED_WARNINGS
# You can also make your code fail to compile if you use deprecated APIs.
# In order to do so, uncomment the following line.
# You can also select to disable deprecated APIs only up to a certain version of Qt.
#DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x060000 # disables all the APIs deprecated before Qt 6.0.0
SOURCES += main.cpp
include(/home/stefano/opencv-4.0.1/opencv.pri)
and main.cpp
#include <QCoreApplication>
#include <QDebug>
#include <opencv2/opencv.hpp>
int main(int argc, char *argv)
{
QCoreApplication a(argc, argv);
qDebug() << "QtCvTest Start";
using namespace cv;
Mat image;
image = imread("/home/stefano/Pictures/2018/02/27/DSC_1421.JPG", CV_LOAD_IMAGE_COLOR);
if(! image.data ) {
qDebug() << "Could not open or find the image";
return -1;
}
namedWindow( "Test", WINDOW_AUTOSIZE );
imshow( "Test", image );
qDebug() << "QtCvTest End";
return a.exec();
}
If I try to compile I get the following error
main.cpp:22: error: undefined reference to `cv::_InputArray::_InputArray(cv::Mat const&)'
any idea how to solve this error?
Thanks in advance for your help
c++ qt opencv
asked Jan 1 at 20:19
StefanoStefano
438
I want to use the OpenCv framework with Qt Applications on Linux (Debian). From https://opencv.org/releases.html I've downloaded the opencv-4.0.1.zip and unzip it into a folder. Then using CMake GUI I've configured the build with BUILD_opencv_world option marked. Then I generate the build and with compiled the library with make and make install and everything seems to be fine.
I've created a opencv.pri file with:
INCLUDE += /usr/local/include
LIBS += -L/usr/local/lib -lopencv_world
To test OpenCv I've created a Qt command line project and try to load an image and display, here the QtCvTest.pro
QT -= gui
CONFIG += c++11 console
CONFIG -= app_bundle
# The following define makes your compiler emit warnings if you use
# any feature of Qt which as been marked deprecated (the exact warnings
# depend on your compiler). Please consult the documentation of the
# deprecated API in order to know how to port your code away from it.
DEFINES += QT_DEPRECATED_WARNINGS
# You can also make your code fail to compile if you use deprecated APIs.
# In order to do so, uncomment the following line.
# You can also select to disable deprecated APIs only up to a certain version of Qt.
#DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x060000 # disables all the APIs deprecated before Qt 6.0.0
SOURCES += main.cpp
include(/home/stefano/opencv-4.0.1/opencv.pri)
and main.cpp
#include <QCoreApplication>
#include <QDebug>
#include <opencv2/opencv.hpp>
int main(int argc, char *argv)
{
QCoreApplication a(argc, argv);
qDebug() << "QtCvTest Start";
using namespace cv;
Mat image;
image = imread("/home/stefano/Pictures/2018/02/27/DSC_1421.JPG", CV_LOAD_IMAGE_COLOR);
if(! image.data ) {
qDebug() << "Could not open or find the image";
return -1;
}
namedWindow( "Test", WINDOW_AUTOSIZE );
imshow( "Test", image );
qDebug() << "QtCvTest End";
return a.exec();
}
If I try to compile I get the following error
main.cpp:22: error: undefined reference to `cv::_InputArray::_InputArray(cv::Mat const&)'
any idea how to solve this error?
Thanks in advance for your help
c++ qt opencv
c++ qt opencv
asked Jan 1 at 20:19
StefanoStefano
438
asked Jan 1 at 20:19
StefanoStefano
438
asked Jan 1 at 20:19
StefanoStefano
438
asked Jan 1 at 20:19
StefanoStefano
438
asked Jan 1 at 20:19
StefanoStefano
438
438
1
changeINCLUDEtoINCLUDEPATH, change-lopencv_worldto-lopencv_imgproc -lopencv_core -lopencv_highgui -lopencv_imgcodecs
– eyllanesc
Jan 1 at 20:49
Or use:CONFIG += link_pkgconfigPKGCONFIG += opencv4
– eyllanesc
Jan 1 at 20:49
Now it works! I've changed toINCLUDEPATHand added the link to opencv_imgproc, opencv_core and opencv_highgui. If I add also opencv_imgcodecs I get an error (-1: error: cannot find -lopencv_imgcodecs). Thanks a lot for your help!
– Stefano
Jan 1 at 22:32
It seems that when you compiled you did not disable a flag that compiles that binary, it does not matter
– eyllanesc
Jan 1 at 22:34
1
with PKGCONFIG + = opencv you are adding all the -l{libs} so your executable is probably very heavy unlike if you add one by one as in the first case so for development use PKGCONFIG and for production I only link the necessary ones.
– eyllanesc
Jan 1 at 22:41
|
show 4 more comments
1
changeINCLUDEtoINCLUDEPATH, change-lopencv_worldto-lopencv_imgproc -lopencv_core -lopencv_highgui -lopencv_imgcodecs
– eyllanesc
Jan 1 at 20:49
Or use:CONFIG += link_pkgconfigPKGCONFIG += opencv4
– eyllanesc
Jan 1 at 20:49
Now it works! I've changed toINCLUDEPATHand added the link to opencv_imgproc, opencv_core and opencv_highgui. If I add also opencv_imgcodecs I get an error (-1: error: cannot find -lopencv_imgcodecs). Thanks a lot for your help!
– Stefano
Jan 1 at 22:32
It seems that when you compiled you did not disable a flag that compiles that binary, it does not matter
– eyllanesc
Jan 1 at 22:34
1
with PKGCONFIG + = opencv you are adding all the -l{libs} so your executable is probably very heavy unlike if you add one by one as in the first case so for development use PKGCONFIG and for production I only link the necessary ones.
– eyllanesc
Jan 1 at 22:41
1
1
change
INCLUDE to INCLUDEPATH, change -lopencv_world to -lopencv_imgproc -lopencv_core -lopencv_highgui -lopencv_imgcodecs– eyllanesc
Jan 1 at 20:49
change
INCLUDE to INCLUDEPATH, change -lopencv_world to -lopencv_imgproc -lopencv_core -lopencv_highgui -lopencv_imgcodecs– eyllanesc
Jan 1 at 20:49
Or use:
CONFIG += link_pkgconfig PKGCONFIG += opencv4– eyllanesc
Jan 1 at 20:49
Or use:
CONFIG += link_pkgconfig PKGCONFIG += opencv4– eyllanesc
Jan 1 at 20:49
Now it works! I've changed to
INCLUDEPATH and added the link to opencv_imgproc, opencv_core and opencv_highgui. If I add also opencv_imgcodecs I get an error (-1: error: cannot find -lopencv_imgcodecs). Thanks a lot for your help!– Stefano
Jan 1 at 22:32
Now it works! I've changed to
INCLUDEPATH and added the link to opencv_imgproc, opencv_core and opencv_highgui. If I add also opencv_imgcodecs I get an error (-1: error: cannot find -lopencv_imgcodecs). Thanks a lot for your help!– Stefano
Jan 1 at 22:32
It seems that when you compiled you did not disable a flag that compiles that binary, it does not matter
– eyllanesc
Jan 1 at 22:34
It seems that when you compiled you did not disable a flag that compiles that binary, it does not matter
– eyllanesc
Jan 1 at 22:34
1
1
with PKGCONFIG + = opencv you are adding all the -l{libs} so your executable is probably very heavy unlike if you add one by one as in the first case so for development use PKGCONFIG and for production I only link the necessary ones.
– eyllanesc
Jan 1 at 22:41
with PKGCONFIG + = opencv you are adding all the -l{libs} so your executable is probably very heavy unlike if you add one by one as in the first case so for development use PKGCONFIG and for production I only link the necessary ones.
– eyllanesc
Jan 1 at 22:41
|
show 4 more comments
1 Answer
1
active
oldest
votes
1
You have to use INCLUDEPATH and the necessary flags for reading and displaying the image in a window:
INCLUDEPATH += /usr/local/include
LIBS += -L/usr/local/lib -lopencv_imgproc -lopencv_core -lopencv_highgui
answered Jan 1 at 22:35
eyllanesceyllanesc
82.3k103259
add a comment |
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You have to use INCLUDEPATH and the necessary flags for reading and displaying the image in a window:
INCLUDEPATH += /usr/local/include
LIBS += -L/usr/local/lib -lopencv_imgproc -lopencv_core -lopencv_highgui
answered Jan 1 at 22:35
eyllanesceyllanesc
82.3k103259
add a comment |
1
You have to use INCLUDEPATH and the necessary flags for reading and displaying the image in a window:
INCLUDEPATH += /usr/local/include
LIBS += -L/usr/local/lib -lopencv_imgproc -lopencv_core -lopencv_highgui
answered Jan 1 at 22:35
eyllanesceyllanesc
82.3k103259
add a comment |
1
1
1
You have to use INCLUDEPATH and the necessary flags for reading and displaying the image in a window:
INCLUDEPATH += /usr/local/include
LIBS += -L/usr/local/lib -lopencv_imgproc -lopencv_core -lopencv_highgui
answered Jan 1 at 22:35
eyllanesceyllanesc
82.3k103259
You have to use INCLUDEPATH and the necessary flags for reading and displaying the image in a window:
INCLUDEPATH += /usr/local/include
LIBS += -L/usr/local/lib -lopencv_imgproc -lopencv_core -lopencv_highgui
answered Jan 1 at 22:35
eyllanesceyllanesc
82.3k103259
answered Jan 1 at 22:35
eyllanesceyllanesc
82.3k103259
answered Jan 1 at 22:35
eyllanesceyllanesc
82.3k103259
answered Jan 1 at 22:35
eyllanesceyllanesc
82.3k103259
82.3k103259
add a comment |
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1
change
INCLUDEtoINCLUDEPATH, change-lopencv_worldto-lopencv_imgproc -lopencv_core -lopencv_highgui -lopencv_imgcodecs– eyllanesc
Jan 1 at 20:49
Or use:
CONFIG += link_pkgconfigPKGCONFIG += opencv4– eyllanesc
Jan 1 at 20:49
Now it works! I've changed to
INCLUDEPATHand added the link to opencv_imgproc, opencv_core and opencv_highgui. If I add also opencv_imgcodecs I get an error (-1: error: cannot find -lopencv_imgcodecs). Thanks a lot for your help!– Stefano
Jan 1 at 22:32
It seems that when you compiled you did not disable a flag that compiles that binary, it does not matter
– eyllanesc
Jan 1 at 22:34
1
with PKGCONFIG + = opencv you are adding all the -l{libs} so your executable is probably very heavy unlike if you add one by one as in the first case so for development use PKGCONFIG and for production I only link the necessary ones.
– eyllanesc
Jan 1 at 22:41