天天向上

#ifndef MAINWINDOW_H

#define MAINWINDOW_H

#include <QMainWindow>

#include <QMenuBar>

#include <QToolBar>

#include <QAction>

#include <QGraphicsScene>

#include <QGraphicsView>

#include <QStatusBar>

#include <QLabel>

#include <QGraphicsPixmapItem>

#include <QFileDialog>

QT_BEGIN_NAMESPACE

namespace Ui { class MainWindow; }

QT_END_NAMESPACE

class MainWindow : public QMainWindow

{

    Q_OBJECT

public:

    MainWindow(QWidget *parent = nullptr);

    ~MainWindow();

private:

    void initUI();

    void createActions();

    void showImage(QString filePath);

    void setupShortcuts();

private slots:

    void openImage();

private:

    Ui::MainWindow *ui;

    QMenu *fileMenu;

    QMenu *viewMenu;

    QToolBar *fileToolBar;

    QToolBar *viewToolBar;

    QGraphicsScene *imageScene;

    QGraphicsView *imageView;

    QStatusBar *mainStatusBar;

    QLabel *mainStatusLabel;

    QAction *openAction;

    QString currentImagePath;

    QGraphicsPixmapItem *currentImage;

};

#endif // MAINWINDOW_H

void MainWindow::initUI()

{

    //this->resize(800,600);

    // setup menubar

    fileMenu = menuBar()->addMenu("&File");

    viewMenu = menuBar()->addMenu("&View");

    // main area for image display

    imageScene = new QGraphicsScene(this);

    imageView = new QGraphicsView(imageScene);

    setCentralWidget(imageView);

    // setup status bar

    mainStatusBar = statusBar();

    mainStatusLabel = new QLabel(mainStatusBar);

    mainStatusBar->addPermanentWidget(mainStatusLabel);

    mainStatusLabel->setText("Image Information:");

}

void MainWindow::createActions()

{

    // create actions, add them to menus

    openAction = new QAction("&Open", this);

    fileMenu->addAction(openAction);

    connect(openAction, SIGNAL(triggered()), this, SLOT(openImage()));

}

void MainWindow::openImage()

{

    QFileDialog dialog(this);

    dialog.setWindowTitle("Open an image file");

    dialog.setFileMode(QFileDialog::ExistingFile);

    dialog.setNameFilter(tr("Images (*.png *bmp *.jpg"));

    QStringList filePaths;

    if(dialog.exec())

    {

        filePaths = dialog.selectedFiles();

        showImage(filePaths.at(0));

    }

}

void MainWindow::showImage(QString filePath)

{

    imageScene->clear();

    imageView->resetMatrix();

    QPixmap image(filePath);

    currentImage = imageScene->addPixmap(image);

    imageScene->update();

    imageView->setSceneRect(image.rect());

    QString info =QString("%1, %2x%3, %4 Bytes").arg(filePath)

                                                .arg(image.width())

                                                .arg(image.height())

                                                .arg(QFile(filePath).size());

    mainStatusLabel->setText(info);

    currentImagePath = filePath;

}