mainwindow.cpp Example File | Qt 4.8 (original) (raw)

widgets/scribble/mainwindow.cpp

#include

#include "mainwindow.h" #include "scribblearea.h"

MainWindow::MainWindow() { scribbleArea = new ScribbleArea; setCentralWidget(scribbleArea);

createActions();
createMenus();

setWindowTitle(tr("Scribble"));
resize(500, 500);

}

void MainWindow::closeEvent(QCloseEvent *event) { if (maybeSave()) { event->accept(); } else { event->ignore(); } }

void MainWindow::open() { if (maybeSave()) { QString fileName = QFileDialog::getOpenFileName(this, tr("Open File"), QDir::currentPath()); if (!fileName.isEmpty()) scribbleArea->openImage(fileName); } }

void MainWindow::save() { QAction *action = qobject_cast<QAction *>(sender()); QByteArray fileFormat = action->data().toByteArray(); saveFile(fileFormat); }

void MainWindow::penColor() { QColor newColor = QColorDialog::getColor(scribbleArea->penColor()); if (newColor.isValid()) scribbleArea->setPenColor(newColor); }

void MainWindow::penWidth() { bool ok; int newWidth = QInputDialog::getInteger(this, tr("Scribble"), tr("Select pen width:"), scribbleArea->penWidth(), 1, 50, 1, &ok); if (ok) scribbleArea->setPenWidth(newWidth); }

void MainWindow::about() { QMessageBox::about(this, tr("About Scribble"), tr("

The Scribble example shows how to use QMainWindow as the " "base widget for an application, and how to reimplement some of " "QWidget's event handlers to receive the events generated for " "the application's widgets:

We reimplement the mouse event " "handlers to facilitate drawing, the paint event handler to " "update the application and the resize event handler to optimize " "the application's appearance. In addition we reimplement the " "close event handler to intercept the close events before " "terminating the application.

The example also demonstrates " "how to use QPainter to draw an image in real time, as well as " "to repaint widgets.

void MainWindow::createActions() { openAct = new QAction(tr("&Open..."), this); openAct->setShortcuts(QKeySequence::Open); connect(openAct, SIGNAL(triggered()), this, SLOT(open()));

foreach ([QByteArray](qbytearray.html) format, [QImageWriter](qimagewriter.html)::supportedImageFormats()) {
    [QString](qstring.html) text = tr("%1...").arg([QString](qstring.html)(format).toUpper());

    [QAction](qaction.html) *action = new [QAction](qaction.html)(text, this);
    action->setData(format);
    connect(action, SIGNAL(triggered()), this, SLOT(save()));
    saveAsActs.append(action);
}

printAct = new [QAction](qaction.html)(tr("&Print..."), this);
connect(printAct, SIGNAL(triggered()), scribbleArea, SLOT(print()));

exitAct = new [QAction](qaction.html)(tr("E&xit"), this);
exitAct->setShortcuts([QKeySequence](qkeysequence.html)::Quit);
connect(exitAct, SIGNAL(triggered()), this, SLOT(close()));

penColorAct = new [QAction](qaction.html)(tr("&Pen Color..."), this);
connect(penColorAct, SIGNAL(triggered()), this, SLOT(penColor()));

penWidthAct = new [QAction](qaction.html)(tr("Pen &Width..."), this);
connect(penWidthAct, SIGNAL(triggered()), this, SLOT(penWidth()));

clearScreenAct = new [QAction](qaction.html)(tr("&Clear Screen"), this);
clearScreenAct->setShortcut(tr("Ctrl+L"));
connect(clearScreenAct, SIGNAL(triggered()),
        scribbleArea, SLOT(clearImage()));

aboutAct = new [QAction](qaction.html)(tr("&About"), this);
connect(aboutAct, SIGNAL(triggered()), this, SLOT(about()));

aboutQtAct = new [QAction](qaction.html)(tr("About &Qt"), this);
connect(aboutQtAct, SIGNAL(triggered()), qApp, SLOT(aboutQt()));

}

void MainWindow::createMenus() { saveAsMenu = new QMenu(tr("&Save As"), this); foreach (QAction *action, saveAsActs) saveAsMenu->addAction(action);

fileMenu = new [QMenu](qmenu.html)(tr("&File"), this);
fileMenu->addAction(openAct);
fileMenu->addMenu(saveAsMenu);
fileMenu->addAction(printAct);
fileMenu->addSeparator();
fileMenu->addAction(exitAct);

optionMenu = new [QMenu](qmenu.html)(tr("&Options"), this);
optionMenu->addAction(penColorAct);
optionMenu->addAction(penWidthAct);
optionMenu->addSeparator();
optionMenu->addAction(clearScreenAct);

helpMenu = new [QMenu](qmenu.html)(tr("&Help"), this);
helpMenu->addAction(aboutAct);
helpMenu->addAction(aboutQtAct);

menuBar()->addMenu(fileMenu);
menuBar()->addMenu(optionMenu);
menuBar()->addMenu(helpMenu);

}

bool MainWindow::maybeSave() { if (scribbleArea->isModified()) { QMessageBox::StandardButton ret; ret = QMessageBox::warning(this, tr("Scribble"), tr("The image has been modified.\n" "Do you want to save your changes?"), QMessageBox::Save | QMessageBox::Discard | QMessageBox::Cancel); if (ret == QMessageBox::Save) { return saveFile("png"); } else if (ret == QMessageBox::Cancel) { return false; } } return true; }

bool MainWindow::saveFile(const QByteArray &fileFormat) { QString initialPath = QDir::currentPath() + "/untitled." + fileFormat;

[QString](qstring.html) fileName = [QFileDialog](qfiledialog.html)::getSaveFileName(this, tr("Save As"),
                           initialPath,
                           tr("%1 Files (*.%2);;All Files (*)")
                           .arg([QString](qstring.html)(fileFormat.toUpper()))
                           .arg([QString](qstring.html)(fileFormat)));
if (fileName.isEmpty()) {
    return false;
} else {
    return scribbleArea->saveImage(fileName, fileFormat);
}

}

© 2016 The Qt Company Ltd. Documentation contributions included herein are the copyrights of their respective owners. The documentation provided herein is licensed under the terms of the GNU Free Documentation License version 1.3 as published by the Free Software Foundation. Qt and respective logos are trademarks of The Qt Company Ltd. in Finland and/or other countries worldwide. All other trademarks are property of their respective owners.