QT5-控件-QScrollArea-可以用于把一个窗口分割为多个-比如根据图片大小显示滚动条

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>
#include <QLabel>
#include <QPixmap>
#include <QImage>
#include <QScrollArea>

class MainWindow : public QMainWindow
{
    Q_OBJECT

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

};

#endif // MAINWINDOW_H

#include "mainwindow.h"

MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent)
{
    this->resize(800,600);
    this->centralWidget();

    QLabel* label = new QLabel(this);
    QImage image("01.jpg");
    label->setPixmap(QPixmap::fromImage(image));
    QScrollArea* area = new QScrollArea(this);
    area->setWidget(label);
    area->setBackgroundRole(QPalette::Dark);
    area->setGeometry(0,0,image.width()+100,image.height()-60);
}

MainWindow::~MainWindow()
{

}

#include "mainwindow.h"
#include <QApplication>

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    MainWindow w;
    w.show();

    return a.exec();
}