The program freezes when an instance of a class is created

jsulm

@gabor53 Can you please show the content of the ImageDisplay constructor, not just its declaration?

gabor53

@jsulm
Here it is:

#include "imagedisplay.h"
#include "ui_imagedisplay.h"

ImageDisplay::ImageDisplay(QWidget *parent) :
    QDialog(parent),
    ui(new Ui::ImageDisplay)
{
    ui->setupUi(this);

    ImageDisplay(imageToEnlarge);
}

ImageDisplay::~ImageDisplay()
{
    delete ui;
}

void ImageDisplay::viewImage(QPixmap imageToEnlarge)
{
    int w = ui->ImageLabel->width ();
    int h = ui->ImageLabel->height ();
    ui->ImageLabel->setPixmap (imageToEnlarge.scaled(w,h,Qt::KeepAspectRatio));
}

Thank you.

mrjj

ImageDisplay::ImageDisplay(QWidget *parent) :
QDialog(parent),
ui(new Ui::ImageDisplay)
{
ui->setupUi(this);
ImageDisplay(imageToEnlarge); <<<<<< Call ctor again !! ?!

should that not be viewImage(QPixmap imageToEnlarge) ?

jsulm

@gabor53 To add to @mrjj: what is imageToEnlarge in

ImageDisplay::ImageDisplay(QWidget *parent) :
    QDialog(parent),
    ui(new Ui::ImageDisplay)
{
    ui->setupUi(this);

    ImageDisplay(imageToEnlarge);
}

kshegunov

How does this even compile? You're not allowed to call constructors explicitly ... probably it creates a temporary ...

VRonin

@kshegunov said in The program freezes when an instance of a class is created:

How does this even compile?

another problem is that in the constructor imageToEnlarge should be an undefined symbol. if it is defined in that constructor then there is a naming conflict in viewImage. this should 100% not compile

gabor53

ImageDisplay::ImageDisplay(QWidget *parent) :
    QDialog(parent),
    ui(new Ui::ImageDisplay)
{
    ui->setupUi(this);

    ImageDisplay(imageToEnlarge);
}

ImageDisplay::~ImageDisplay()

I deleted ImageDisplay(imageToEnlarge). As a result it doesn't freeze but doesn't display the image I clicked on either.

josephdp

As what others suggested, the content of the form constructor is wrong.
Your widgets are already taken care of by setupUI().
Thus, the logic of displaying the image should just be in viewImage ().

QPixmap imageToEnlarge = index.data(Qt::DecorationRole).value<QPixmap>();

where is the data in this?

here's a brief example using QT's QImage.

QPixmap scaledPixmap = QPixmap::fromImage (image).scaled (
    QSize (w, h),
    Qt::IgnoreAspectRatio, Qt::SmoothTransformation);

ui->ImageLabel->setPixmap (scaledPixmap);

gabor53

The following seems to work:

void MainWindow::on_tableView_clicked(const QModelIndex &index)
{
    int row = index.row ();
    int column = index.column ();
    qDebug() << "Index: " << "(" << row <<"," << column << ")";

    if(column == 2)
        {
            qDebug() << "Column 2 was chosen.";

            QPixmap imageToEnlarge = index.data(Qt::DecorationRole).value<QPixmap>();

            int w = ui->label_Temp->width();
            int h = ui->label_Temp->height ();
            ui->label_Temp->setPixmap (imageToEnlarge.scaled(w,h,Qt::KeepAspectRatio));
            ImageDisplay *mImageDisplay = new ImageDisplay;
            mImageDisplay->viewImage(imageToEnlarge);
            mImageDisplay->exec ();

        }
}

Thank you for your help.

mrjj

super
You should get rid of new or add a delete

ImageDisplay *mImageDisplay = new ImageDisplay;
mImageDisplay->viewImage(imageToEnlarge);
mImageDisplay->exec ();
delete ImageDisplay; /// clean up

or simply dont use new as you use exec()

ImageDisplay mImageDisplay;
mImageDisplay.viewImage(imageToEnlarge);
mImageDisplay.exec ();

gabor53

Thank you!!