- Qt 5.5
- Qt Widgets
- Weather Anchor Layout Example
- main.cpp Example File
- Qt 5.5.1 Reference Documentation

# main.cpp Example File

graphicsview/weatheranchorlayout/main.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.
    **
    ** $QT_BEGIN_LICENSE:BSD$
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    #include <QApplication>
    #include <QLabel>
    #include <QPainter>
    #include <QPushButton>

    #include <QGraphicsAnchorLayout>
    #include <QGraphicsProxyWidget>
    #include <QGraphicsScene>
    #include <QGraphicsSceneResizeEvent>
    #include <QGraphicsView>
    #include <QGraphicsWidget>

    class GraphicsView : public QGraphicsView
    {
    public:
        GraphicsView(QGraphicsScene *scene, QGraphicsWidget *widget)
            : QGraphicsView(scene), w(widget)
        {
        }

        virtual void resizeEvent(QResizeEvent *event) Q_DECL_OVERRIDE
        {
            w->setGeometry(0, 0, event->size().width(), event->size().height());
        }

        QGraphicsWidget *w;
    };

    class PixmapWidget : public QGraphicsLayoutItem
    {

    public:
        PixmapWidget(const QPixmap &pix)
            : QGraphicsLayoutItem()
        {
            original = new QGraphicsPixmapItem(pix);
            setGraphicsItem(original);
            original->show();
            r = QRectF(QPointF(0, 0), pix.size());
        }

        ~PixmapWidget()
        {
            setGraphicsItem(0);
            delete original;
        }

        void setZValue(qreal z)
        {
            original->setZValue(z);
        }

        void setGeometry (const QRectF &rect) Q_DECL_OVERRIDE
        {
            original->setTransform(QTransform::fromScale(rect.width() / r.width(),
                                                         rect.height() / r.height()), true);
            original->setPos(rect.x(), rect.y());
            r = rect;
        }

    protected:
        QSizeF sizeHint(Qt::SizeHint which, const QSizeF &constraint = QSizeF()) const Q_DECL_OVERRIDE
        {
            Q_UNUSED(constraint);
            QSizeF sh;
            switch (which) {
                case Qt::MinimumSize:
                    sh = QSizeF(0, 0);
                    break;
                case Qt::PreferredSize:
                    sh = QSizeF(50, 50);
                    break;
                case Qt::MaximumSize:
                    sh = QSizeF(QWIDGETSIZE_MAX, QWIDGETSIZE_MAX);
                    break;
                default:
                    break;
            }
            return sh;
        }

    private:
        QGraphicsPixmapItem *original;
        QRectF r;
    };

    class PlaceWidget : public QGraphicsWidget
    {
        Q_OBJECT

    public:
        PlaceWidget(const QPixmap &pix)
            : QGraphicsWidget()
            , original(pix)
            , scaled(pix)
        {
        }

        void paint(QPainter *painter, const QStyleOptionGraphicsItem*, QWidget*) Q_DECL_OVERRIDE
        {
            QPointF reflection = QPointF();
            reflection.setY(scaled.height() + 2);

            painter->drawPixmap(QPointF(), scaled);

            QPixmap tmp(scaled.size());
            tmp.fill(Qt::transparent);
            QPainter p(&tmp);

            // create gradient
            QPoint p1(scaled.width() / 2, 0);
            QPoint p2(scaled.width() / 2, scaled.height());
            QLinearGradient linearGrad(p1, p2);
            linearGrad.setColorAt(0, QColor(0, 0, 0, 0));
            linearGrad.setColorAt(0.65, QColor(0, 0, 0, 127));
            linearGrad.setColorAt(1, QColor(0, 0, 0, 255));

            // apply 'mask'
            p.setBrush(linearGrad);
            p.fillRect(0, 0, tmp.width(), tmp.height(), QBrush(linearGrad));
            p.fillRect(0, 0, tmp.width(), tmp.height(), QBrush(linearGrad));

            // paint the image flipped
            p.setCompositionMode(QPainter::CompositionMode_DestinationOver);
            p.drawPixmap(0, 0, QPixmap::fromImage(scaled.toImage().mirrored(false, true)));
            p.end();

            painter->drawPixmap(reflection, tmp);
        }

        void resizeEvent(QGraphicsSceneResizeEvent *event) Q_DECL_OVERRIDE
        {
            QSize newSize = event->newSize().toSize();
            newSize.setHeight(newSize.height() / 2);
            scaled = original.scaled(newSize);
        }

        QRectF boundingRect() const Q_DECL_OVERRIDE
        {
            QSize size(scaled.width(), scaled.height() * 2 + 2);
            return QRectF(QPointF(0, 0), size);
        }

    private:
        QPixmap original;
        QPixmap scaled;
    };

    int main(int argc, char *argv[])
    {
        Q_INIT_RESOURCE(weatheranchorlayout);

        QApplication app(argc, argv);

        QGraphicsScene scene;
        scene.setSceneRect(0, 0, 800, 480);

        // pixmaps widgets
        PixmapWidget *title = new PixmapWidget(QPixmap(":/images/title.jpg"));
        PlaceWidget *place = new PlaceWidget(QPixmap(":/images/place.jpg"));
        PixmapWidget *details = new PixmapWidget(QPixmap(":/images/5days.jpg"));
        PixmapWidget *sunnyWeather = new PixmapWidget(QPixmap(":/images/weather-few-clouds.png"));
        PixmapWidget *tabbar = new PixmapWidget(QPixmap(":/images/tabbar.jpg"));

        // setup sizes
        title->setPreferredSize(QSizeF(348, 45));
        title->setSizePolicy(QSizePolicy::Minimum, QSizePolicy::Minimum);

        place->setPreferredSize(QSizeF(96, 72));
        place->setSizePolicy(QSizePolicy::Minimum, QSizePolicy::Minimum);

        details->setMinimumSize(QSizeF(200, 112));
        details->setPreferredSize(QSizeF(200, 112));
        details->setSizePolicy(QSizePolicy::Minimum, QSizePolicy::Minimum);

        tabbar->setPreferredSize(QSizeF(70, 24));
        tabbar->setSizePolicy(QSizePolicy::Minimum, QSizePolicy::Minimum);

        sunnyWeather->setPreferredSize(QSizeF(128, 97));
        sunnyWeather->setSizePolicy(QSizePolicy::Minimum, QSizePolicy::Minimum);
        sunnyWeather->setZValue(9999);

        // start anchor layout
        QGraphicsAnchorLayout *layout = new QGraphicsAnchorLayout;
        layout->setSpacing(0);

        // setup the main widget
        QGraphicsWidget *widget = new QGraphicsWidget(0, Qt::Window);
        QPalette p;
        p.setColor(QPalette::Window, Qt::black);
        widget->setPalette(p);
        widget->setPos(20, 20);
        widget->setLayout(layout);

        // vertical anchors
        QGraphicsAnchor *anchor = layout->addAnchor(title, Qt::AnchorTop, layout, Qt::AnchorTop);
        anchor = layout->addAnchor(place, Qt::AnchorTop, title, Qt::AnchorBottom);
        anchor->setSpacing(12);
        anchor = layout->addAnchor(place, Qt::AnchorBottom, layout, Qt::AnchorBottom);
        anchor->setSpacing(12);

        anchor = layout->addAnchor(sunnyWeather, Qt::AnchorTop, title, Qt::AnchorTop);
        anchor = layout->addAnchor(sunnyWeather, Qt::AnchorBottom, layout, Qt::AnchorVerticalCenter);

        anchor = layout->addAnchor(tabbar, Qt::AnchorTop, title, Qt::AnchorBottom);
        anchor->setSpacing(5);
        anchor = layout->addAnchor(details, Qt::AnchorTop, tabbar, Qt::AnchorBottom);
        anchor->setSpacing(2);
        anchor = layout->addAnchor(details, Qt::AnchorBottom, layout, Qt::AnchorBottom);
        anchor->setSpacing(12);

        // horizontal anchors
        anchor = layout->addAnchor(layout, Qt::AnchorLeft, title, Qt::AnchorLeft);
        anchor = layout->addAnchor(title, Qt::AnchorRight, layout, Qt::AnchorRight);

        anchor = layout->addAnchor(place, Qt::AnchorLeft, layout, Qt::AnchorLeft);
        anchor->setSpacing(15);
        anchor = layout->addAnchor(place, Qt::AnchorRight, details, Qt::AnchorLeft);
        anchor->setSpacing(35);

        anchor = layout->addAnchor(sunnyWeather, Qt::AnchorLeft, place, Qt::AnchorHorizontalCenter);
        anchor = layout->addAnchor(sunnyWeather, Qt::AnchorRight, layout, Qt::AnchorHorizontalCenter);

        anchor = layout->addAnchor(tabbar, Qt::AnchorHorizontalCenter, details, Qt::AnchorHorizontalCenter);
        anchor = layout->addAnchor(details, Qt::AnchorRight, layout, Qt::AnchorRight);

        // QGV setup
        scene.addItem(widget);
        scene.setBackgroundBrush(Qt::white);
        QGraphicsView *view = new QGraphicsView(&scene);
        view->show();

        return app.exec();
    }

    #include "main.moc"