Exercise: drawImage

In this exercise, simple show a picture using drawImage().


Create a Qt4 GUI Application, download the picture and save in the project directory, named "qtman.jpg".



Modify mainwindow.h and mainwindow.cpp

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QtGui/QMainWindow>

namespace Ui
{
    class MainWindow;
}

class MainWindow : public QMainWindow
{
    Q_OBJECT

    public:
         MainWindow(QWidget *parent = 0);
         ~MainWindow();

    private:
         Ui::MainWindow *ui;
         void paintEvent(QPaintEvent*);
};

#endif // MAINWINDOW_H

mainwindow.h

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <QPainter>

MainWindow::MainWindow(QWidget *parent)
: QMainWindow(parent), ui(new Ui::MainWindow)
{
   ui->setupUi(this);
}

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

void MainWindow::paintEvent(QPaintEvent *event)
{
    QImage image("qtman.jpg");
    QRect rect(0, 0, image.width(), image.height());    //define the area used to display
    QPainter painter(this);

    painter.drawImage(rect, image);
}

mainwindow.cpp