void MainWindow::slotConstructWaterBodies(const QString& mapName, const QString& mapImagePath)
{
    ui->mylabel->setPixmap(mapImagePath);
    /*Прочий код*/
}

void MainWindow::resizeEvent(QResizeEvent *event)
{
    adjustWidgetSize();

    QMainWindow::resizeEvent(event);
}

void MainWindow::adjustWidgetSize()
{
    int widthCurrentPixMap = 1;
        int heightCurrentPixMap = 1;

        if(pixPtr_) {
            widthCurrentPixMap = pixPtr_->width();
            heightCurrentPixMap = pixPtr_->height();
        }
        const QSize pixmapSize(widthCurrentPixMap, heightCurrentPixMap);

        ui->mylabel->setFixedWidth(
            ui->centralWidget->height() * pixmapSize.width() / pixmapSize.height()
        );
}

void MainWindow::slotConstructWaterBodies(const QString& mapName, const QString& mapImagePath)
    {
        QPixmap *pixmap = new QPixmap(mapImagePath);
        pixPtr_ = pixmap;

        QGraphicsScene *scene = new QGraphicsScene;
        QGraphicsPixmapItem *item = new QGraphicsPixmapItem(*pixPtr_);
        item->setTransformationMode(Qt::SmoothTransformation);
        scene->addItem(item);
        ui->graphicsViewMap->setScene(scene);
        ui->graphicsViewMap->fitInView(scene->sceneRect(), Qt::IgnoreAspectRatio);

        /*Прочий код*/
    }

    void MainWindow::resizeEvent(QResizeEvent *event)
    {
        adjustWidgetSize();

        adjustScaledPixmap();

        QMainWindow::resizeEvent(event);
    }

    void MainWindow::adjustWidgetSize()
    {
        int widthCurrentPixMap = 1;
            int heightCurrentPixMap = 1;

            if(pixPtr_) {
                widthCurrentPixMap = pixPtr_->width();
                heightCurrentPixMap = pixPtr_->height();
            }
            const QSize pixmapSize(widthCurrentPixMap, heightCurrentPixMap);

            ui->graphicsViewMap->setFixedWidth(
                ui->centralWidget->height() * pixmapSize.width() / pixmapSize.height()
            );
    }

    void MainWindow::adjustScaledPixmap()
    {
        QGraphicsScene *scene = new QGraphicsScene;
        QGraphicsPixmapItem *item = new QGraphicsPixmapItem(*pixPtr_);
        item->setTransformationMode(Qt::SmoothTransformation);
        scene->addItem(item);
        ui->graphicsViewMap->setScene(scene);
        ui->graphicsViewMap->fitInView(scene->sceneRect(), Qt::IgnoreAspectRatio);
    }