Problem in show image in a MainWindow
-
I'm trying to create a simple program that load an image from a file and show it in my MainWindow using opencv and Qt!
The problems are 2:- When I load the image, it show it in the MainWindow only after use imshow! If I try to delete imshow from the list of operation to do, the program crashes!
- I inserted the code explained before in a function and I would like to call it continuosly, but only after the pressing of a button!
The problem is that if I try to call the function by on_pushButton_clicked() the system crashes, instead if I call it at the start (in main() ) it works fine!
What should be the problem? How can I solve it?
Here I will copy the code:
main.cpp
@
#include <QtGui/QApplication>#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <unistd.h>
int cattura_avviata=0;
int main(int argc, char *argv[])
{
QApplication a(argc, argv); MainWindow w; w.show(); terminale=0; //cattura_avviata=1; //w.cattura(); return a.exec();}
int MainWindow::get_cattura_avviata()
{
return cattura_avviata;}
void MainWindow::set_cattura_avviata(int var)
{
cattura_avviata=var;}
void MainWindow::cattura()
{
CvCapture *input; const char *fileName = "C:/Users/Lifedj/Documents/video_2_converted.mp4"; input = cvCaptureFromFile(fileName); Mat frame; if (!input) { std::cout << "Can't open file" << fileName; } else { frame = cvQueryFrame( input ); if( !frame.empty() ) { cvtColor(frame, frame, CV_BGR2RGB); QImage immagine_convertita= QImage((uchar*) frame.data, frame.cols, frame.rows, frame.step, QImage::Format_RGB888); QImage small = immagine_convertita.scaled(400, 900,Qt::KeepAspectRatio); this->ui->label->setPixmap(QPixmap::fromImage(small)); imshow( window_name, frame ); //this is the instruction that I would like to eliminate } else { printf("%s -> %d \n",data_e_ora.toAscii().constData(),num_per); } } else { printf(" --(!) No captured frame -- Break!"); } int c = waitKey(1); if( (char)c == 'c' ) { cattura_avviata=0; } } //} cvReleaseCapture(&input); if (cattura_avviata==1) { cattura(); } return;}
@
mainwindow.cpp
@
void MainWindow::on_pushButton_clicked(){
MainWindow w; if (w.get_cattura_avviata()==0) { ui->pushButton->setText("Ferma riconoscimento"); w.set_cattura_avviata(1); w.cattura(); } else { ui->pushButton->setText("Avvia riconoscimento"); w.set_cattura_avviata(0); }}
@
Thank you in advance!
-
For the crash part, are you sure you have initialized everything ?
About your code:
In on_push_button_clicked, you create a new MainWindow and do everything in there that is related to your image reading/showing, without even showing that MainWindow.I think the best would be to first, get your user interface clean and running and only then add the OpenCV part.
