我将尝试使用
QGraphicsView
创建一个简单的应用程序。该应用程序可以在视图中加载具有不同比例的图形文件。我想要实现以下功能:当应用程序窗口大小调整时,视图的内容也应该被调整并居中显示。由于我不太了解Qt的这一部分,因此我可以调整内容的大小,但无法使其居中。我该如何解决?
MainWindow.h
代码片段:class MainWindow : public QMainWindow
{
Q_OBJECT
public:
MainWindow(QWidget *parent = 0);
~MainWindow();
void resizeEvent(QResizeEvent *event) override;
public slots:
void onButtonClicked();
private:
bool m_flag = false;
QGraphicsPixmapItem *m_item = nullptr;
QGraphicsView *m_view = nullptr;
QPixmap m_pixmap;
};
MainWindow.cpp
:
MainWindow::MainWindow(QWidget *parent)
: QMainWindow(parent)
{
auto central = new QWidget(this);
setCentralWidget(central);
// layouts
auto mainLayout = new QVBoxLayout;
mainLayout->setAlignment(Qt::AlignTop);
central->setLayout(mainLayout);
// top layout
auto topLayout = new QHBoxLayout;
topLayout->setAlignment(Qt::AlignLeft);
mainLayout->addLayout(topLayout);
auto btn = new QPushButton(this);
btn->setText("Test");
connect(btn, &QPushButton::clicked, this, &MainWindow::onButtonClicked);
topLayout->addWidget(btn);
m_view = new QGraphicsView;
mainLayout->addWidget(m_view);
auto scene = new QGraphicsScene;
m_view->setScene(scene);
m_view->setMinimumSize(800, 600);
m_view->setHorizontalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
m_view->setVerticalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
QString name = ":/pic1.jpg";
m_pixmap = QPixmap{ name }.scaled(800, 600, Qt::KeepAspectRatio);
m_item = scene->addPixmap(m_pixmap);
m_view->viewport()->resize(m_pixmap.size());
}
void MainWindow::onButtonClicked()
{
m_flag = !m_flag;
QString name = m_flag ? ":/pic2.png" : ":/pic1.jpg";
m_pixmap = QPixmap{ name }.scaled(m_view->size(), Qt::KeepAspectRatio);
m_item->setPixmap(m_pixmap);
m_view->fitInView(m_item, Qt::KeepAspectRatio);
}
void MainWindow::resizeEvent(QResizeEvent *event)
{
QMainWindow::resizeEvent(event);
m_view->fitInView(m_item, Qt::KeepAspectRatio);
}