Error code after inheriting QGraphicsView

[K.Sejdak]

Hi everyone!

I have some problem with QGraphicsView. I want to create a program that will allow me to draw rectangles on loaded image. I have created my own GraphicsView class that inherits from QGraphicsView and I have overloaded QGraphicsView::mouseReleaseEvent to get the mouse position. I also added 'Widget' from Qt Creator to my form and replaced it with my class. It works fine until I close the window. After that I get an error code (-1073741819). Debugger shows segmentation fault in function QScopedPointer (no idea why). Probably I have to call some function, but I don't know which one and where. I will show you my code (only .cpp). Tell me if you need the header files.

I hope you understand what I mean Could you help me?

MainWindow class:

#include "MainWindow.h"
#include "ui_MainWindow.h"
 
MainWindow::MainWindow(QWidget *parent) : QWidget(parent), ui(new Ui::MainWindow)
{
    ui->setupUi(this);
	ui->widget->setScene(&scene);
 
	connect(ui->closeButton, SIGNAL(clicked()), this, SLOT(close()));
	connect(ui->loadButton, SIGNAL(clicked()), this, SLOT(loadImage()));
}
 
MainWindow::~MainWindow()
{
    delete ui;
}
 
void MainWindow::loadImage()
{
	QString fileName = QFileDialog::getOpenFileName();
	image.load(fileName);
	scene.addPixmap(image);
	ui->widget->loadImage(image);
	ui->widget->show();
}

#include "MainWindow.h"
#include "ui_MainWindow.h"

MainWindow::MainWindow(QWidget *parent) : QWidget(parent), ui(new Ui::MainWindow)
{
    ui->setupUi(this);
	ui->widget->setScene(&scene);

	connect(ui->closeButton, SIGNAL(clicked()), this, SLOT(close()));
	connect(ui->loadButton, SIGNAL(clicked()), this, SLOT(loadImage()));
}

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

void MainWindow::loadImage()
{
	QString fileName = QFileDialog::getOpenFileName();
	image.load(fileName);
	scene.addPixmap(image);
	ui->widget->loadImage(image);
	ui->widget->show();
}

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GraphicsView class:

#include "GraphicsView.h"
 
GraphicsView::GraphicsView(QWidget *parent) : QGraphicsView(parent)
{
	firstRect = true;
}
 
GraphicsView::~GraphicsView()
{
	scene()->clear();
}
 
void GraphicsView::loadImage(QPixmap item)
{
	image = item;
}
 
void GraphicsView::mouseReleaseEvent(QMouseEvent *event)
{
	if(point1.isNull())
	{
		point1.setX(event->x());
		point1.setY(event->y());
	}
	else
	{
		point2.setX(event->x());
		point2.setY(event->y());
		int width = point2.x() - point1.x();
		int height = point2.y() - point1.y();
 
		if(firstRect)
		{
			rect.setRect(point1.x(), point1.y(), width, height);
			rect.setPen(QPen(Qt::red));
			firstRect = false;
		}
		else
		{
			scene()->removeItem(&rect);
			rect.setRect(point1.x(), point1.y(), width, height);
		}
 
		scene()->clear();
		scene()->addPixmap(image);
		scene()->addItem(&rect);
 
		point1.setX(0);
		point1.setY(0);
	}
 
	event->accept();
}

#include "GraphicsView.h"

GraphicsView::GraphicsView(QWidget *parent) : QGraphicsView(parent)
{
	firstRect = true;
}

GraphicsView::~GraphicsView()
{
	scene()->clear();
}

void GraphicsView::loadImage(QPixmap item)
{
	image = item;
}

void GraphicsView::mouseReleaseEvent(QMouseEvent *event)
{
	if(point1.isNull())
	{
		point1.setX(event->x());
		point1.setY(event->y());
	}
	else
	{
		point2.setX(event->x());
		point2.setY(event->y());
		int width = point2.x() - point1.x();
		int height = point2.y() - point1.y();

		if(firstRect)
		{
			rect.setRect(point1.x(), point1.y(), width, height);
			rect.setPen(QPen(Qt::red));
			firstRect = false;
		}
		else
		{
			scene()->removeItem(&rect);
			rect.setRect(point1.x(), point1.y(), width, height);
		}

		scene()->clear();
		scene()->addPixmap(image);
		scene()->addItem(&rect);

		point1.setX(0);
		point1.setY(0);
	}

	event->accept();
}

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Platform: Windows 7
Qt: 4.7.0

Thanks in advance
Kuba