- Qt 5.5
- Qt Widgets
- Basic Graphics Layouts Example
- layoutitem.cpp Example File
- Qt 5.5.1 Reference Documentation

# layoutitem.cpp Example File

graphicsview/basicgraphicslayouts/layoutitem.cpp

    /****************************************************************************
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    ** Copyright (C) 2015 The Qt Company Ltd.
    ** Contact: http://www.qt.io/licensing/
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    ** This file is part of the examples of the Qt Toolkit.
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    #include "layoutitem.h"

    #include <QGradient>
    #include <QGraphicsLinearLayout>
    #include <QPainter>

    LayoutItem::LayoutItem(QGraphicsItem *parent/* = 0*/)
        : QGraphicsLayoutItem(), QGraphicsItem(parent)
    {
        m_pix = new QPixmap(QLatin1String(":/images/block.png"));
        setGraphicsItem(this);
    }

    LayoutItem::~LayoutItem()
    {
        delete m_pix;
    }

    void LayoutItem::paint(QPainter *painter,
        const QStyleOptionGraphicsItem *option, QWidget *widget /*= 0*/)
    {
        Q_UNUSED(widget);
        Q_UNUSED(option);

        QRectF frame(QPointF(0,0), geometry().size());
        qreal w = m_pix->width();
        qreal h = m_pix->height();
        QGradientStops stops;

        // paint a background rect (with gradient)
        QLinearGradient gradient(frame.topLeft(), frame.topLeft() + QPointF(200,200));
        stops << QGradientStop(0.0, QColor(60, 60,  60));
        stops << QGradientStop(frame.height() / 2 / frame.height(), QColor(102, 176, 54));

        //stops << QGradientStop(((frame.height() + h)/2 )/frame.height(), QColor(157, 195,  55));
        stops << QGradientStop(1.0, QColor(215, 215, 215));
        gradient.setStops(stops);
        painter->setBrush(QBrush(gradient));
        painter->drawRoundedRect(frame, 10.0, 10.0);

        // paint a rect around the pixmap (with gradient)
        QPointF pixpos = frame.center() - (QPointF(w, h) / 2);
        QRectF innerFrame(pixpos, QSizeF(w, h));
        innerFrame.adjust(-4, -4, 4, 4);
        gradient.setStart(innerFrame.topLeft());
        gradient.setFinalStop(innerFrame.bottomRight());
        stops.clear();
        stops << QGradientStop(0.0, QColor(215, 255, 200));
        stops << QGradientStop(0.5, QColor(102, 176, 54));
        stops << QGradientStop(1.0, QColor(0, 0,  0));
        gradient.setStops(stops);
        painter->setBrush(QBrush(gradient));
        painter->drawRoundedRect(innerFrame, 10.0, 10.0);
        painter->drawPixmap(pixpos, *m_pix);
    }

    QRectF LayoutItem::boundingRect() const
    {
        return QRectF(QPointF(0,0), geometry().size());
    }

    void LayoutItem::setGeometry(const QRectF &geom)
    {
        prepareGeometryChange();
        QGraphicsLayoutItem::setGeometry(geom);
        setPos(geom.topLeft());
    }

    QSizeF LayoutItem::sizeHint(Qt::SizeHint which, const QSizeF &constraint) const
    {
        switch (which) {
        case Qt::MinimumSize:
        case Qt::PreferredSize:
            // Do not allow a size smaller than the pixmap with two frames around it.
            return m_pix->size() + QSize(12, 12);
        case Qt::MaximumSize:
            return QSizeF(1000,1000);
        default:
            break;
        }
        return constraint;
    }