- Qt 5.5
- Qt Widgets
- Drag and Drop Puzzle Example
- mainwindow.cpp Example File
- Qt 5.5.1 Reference Documentation

# mainwindow.cpp Example File

draganddrop/puzzle/mainwindow.cpp

    /****************************************************************************
    **
    ** Copyright (C) 2015 The Qt Company Ltd.
    ** Contact: http://www.qt.io/licensing/
    **
    ** This file is part of the examples of the Qt Toolkit.
    **
    ** $QT_BEGIN_LICENSE:BSD$
    ** You may use this file under the terms of the BSD license as follows:
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    **     from this software without specific prior written permission.
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    #include "mainwindow.h"
    #include "pieceslist.h"
    #include "puzzlewidget.h"

    #include <QtWidgets>
    #include <stdlib.h>

    MainWindow::MainWindow(QWidget *parent)
        : QMainWindow(parent)
    {
        setupMenus();
        setupWidgets();

        setSizePolicy(QSizePolicy(QSizePolicy::Fixed, QSizePolicy::Fixed));
        setWindowTitle(tr("Puzzle"));
    }

    void MainWindow::openImage(const QString &path)
    {
        QString fileName = path;

        if (fileName.isNull()) {
            fileName = QFileDialog::getOpenFileName(this,
                tr("Open Image"), "", "Image Files (*.png *.jpg *.bmp)");
        }

        if (!fileName.isEmpty()) {
            QPixmap newImage;
            if (!newImage.load(fileName)) {
                QMessageBox::warning(this, tr("Open Image"),
                                      tr("The image file could not be loaded."),
                                      QMessageBox::Cancel);
                return;
            }
            puzzleImage = newImage;
            setupPuzzle();
        }
    }

    void MainWindow::setCompleted()
    {
        QMessageBox::information(this, tr("Puzzle Completed"),
                                 tr("Congratulations! You have completed the puzzle!\n"
                                    "Click OK to start again."),
                                 QMessageBox::Ok);

        setupPuzzle();
    }

    void MainWindow::setupPuzzle()
    {
        int size = qMin(puzzleImage.width(), puzzleImage.height());
        puzzleImage = puzzleImage.copy((puzzleImage.width() - size)/2,
            (puzzleImage.height() - size)/2, size, size).scaled(puzzleWidget->width(),
                puzzleWidget->height(), Qt::IgnoreAspectRatio, Qt::SmoothTransformation);

        piecesList->clear();

        for (int y = 0; y < 5; ++y) {
            for (int x = 0; x < 5; ++x) {
                int pieceSize = puzzleWidget->pieceSize();
                QPixmap pieceImage = puzzleImage.copy(x * pieceSize, y * pieceSize, pieceSize, pieceSize);
                piecesList->addPiece(pieceImage, QPoint(x, y));
            }
        }

        qsrand(QCursor::pos().x() ^ QCursor::pos().y());

        for (int i = 0; i < piecesList->count(); ++i) {
            if (int(2.0*qrand()/(RAND_MAX+1.0)) == 1) {
                QListWidgetItem *item = piecesList->takeItem(i);
                piecesList->insertItem(0, item);
            }
        }

        puzzleWidget->clear();
    }

    void MainWindow::setupMenus()
    {
        QMenu *fileMenu = menuBar()->addMenu(tr("&File"));

        QAction *openAction = fileMenu->addAction(tr("&Open..."));
        openAction->setShortcuts(QKeySequence::Open);

        QAction *exitAction = fileMenu->addAction(tr("E&xit"));
        exitAction->setShortcuts(QKeySequence::Quit);

        QMenu *gameMenu = menuBar()->addMenu(tr("&Game"));

        QAction *restartAction = gameMenu->addAction(tr("&Restart"));

        connect(openAction, SIGNAL(triggered()), this, SLOT(openImage()));
        connect(exitAction, SIGNAL(triggered()), qApp, SLOT(quit()));
        connect(restartAction, SIGNAL(triggered()), this, SLOT(setupPuzzle()));
    }

    void MainWindow::setupWidgets()
    {
        QFrame *frame = new QFrame;
        QHBoxLayout *frameLayout = new QHBoxLayout(frame);
        puzzleWidget = new PuzzleWidget(400);

        piecesList = new PiecesList(puzzleWidget->pieceSize(), this);

        connect(puzzleWidget, SIGNAL(puzzleCompleted()),
                this, SLOT(setCompleted()), Qt::QueuedConnection);

        frameLayout->addWidget(piecesList);
        frameLayout->addWidget(puzzleWidget);
        setCentralWidget(frame);
    }