qt5base-lts/examples/widgets/graphicsview/weatheranchorlayout/main.cpp

// Copyright (C) 2016 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause

#include <QApplication>
#include <QLabel>
#include <QGraphicsAnchorLayout>
#include <QGraphicsProxyWidget>
#include <QGraphicsScene>
#include <QGraphicsSceneResizeEvent>
#include <QGraphicsView>
#include <QGraphicsWidget>
#include <QPainter>
#include <QPushButton>


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

    void resizeEvent(QResizeEvent *event) 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))
        , r(QRectF(QPointF(0, 0), pix.size()))
    {
        setGraphicsItem(original);
        original->show();
    }

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

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

    void setGeometry(const QRectF &rect) 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 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 *) override
    {
        const QPointF reflection(0, 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) override
    {
        QSize newSize = event->newSize().toSize();
        newSize.setHeight(newSize.height() / 2);
        scaled = original.scaled(newSize);
    }

    QRectF boundingRect() const 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(nullptr, 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"