- Qt 5.5
- Qt Widgets
- Blur Picker Effect Example
- blurpicker.cpp Example File
- Qt 5.5.1 Reference Documentation

# blurpicker.cpp Example File

effects/blurpicker/blurpicker.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 "blurpicker.h"

    #include <QtWidgets>
    #include <QtCore/qmath.h>

    #include "blureffect.h"

    #ifndef M_PI
    #define M_PI 3.14159265358979323846
    #endif

    BlurPicker::BlurPicker(QWidget *parent): QGraphicsView(parent), m_index(0.0), m_animation(this, "index")
    {
        setBackgroundBrush(QPixmap(":/images/background.jpg"));
        setScene(new QGraphicsScene(this));

        setupScene();
        setIndex(0);

        m_animation.setDuration(400);
        m_animation.setEasingCurve(QEasingCurve::InOutSine);

        setRenderHint(QPainter::Antialiasing, true);
        setFrameStyle(QFrame::NoFrame);
    }

    qreal BlurPicker::index() const
    {
        return m_index;
    }

    void BlurPicker::setIndex(qreal index)
    {
        m_index = index;

        qreal baseline = 0;
        for (int i = 0; i < m_icons.count(); ++i) {
            QGraphicsItem *icon = m_icons[i];
            qreal a = ((i + m_index) * 2 * M_PI) / m_icons.count();
            qreal xs = 170 * qSin(a);
            qreal ys = 100 * qCos(a);
            QPointF pos(xs, ys);
            pos = QTransform().rotate(-20).map(pos);
            pos -= QPointF(40, 40);
            icon->setPos(pos);
            baseline = qMax(baseline, ys);
            static_cast<BlurEffect *>(icon->graphicsEffect())->setBaseLine(baseline);
        }

        scene()->update();
    }

    void BlurPicker::setupScene()
    {
        scene()->setSceneRect(-200, -120, 400, 240);

        QStringList names;
        names << ":/images/accessories-calculator.png";
        names << ":/images/accessories-text-editor.png";
        names << ":/images/help-browser.png";
        names << ":/images/internet-group-chat.png";
        names << ":/images/internet-mail.png";
        names << ":/images/internet-web-browser.png";
        names << ":/images/office-calendar.png";
        names << ":/images/system-users.png";

        for (int i = 0; i < names.count(); i++) {
            QPixmap pixmap(names[i]);
            QGraphicsPixmapItem *icon = scene()->addPixmap(pixmap);
            icon->setZValue(1);
            icon->setGraphicsEffect(new BlurEffect(icon));
            m_icons << icon;
        }

        QGraphicsPixmapItem *bg = scene()->addPixmap(QPixmap(":/images/background.jpg"));
        bg->setZValue(0);
        bg->setPos(-200, -150);
    }

    void BlurPicker::keyPressEvent(QKeyEvent *event)
    {
        int delta = 0;
        switch (event->key())
        {
        case Qt::Key_Left:
            delta = -1;
            break;
        case  Qt::Key_Right:
            delta = 1;
            break;
        default:
            break;
        }
        if (m_animation.state() == QAbstractAnimation::Stopped && delta) {
            m_animation.setEndValue(m_index + delta);
            m_animation.start();
            event->accept();
        }
    }

    void BlurPicker::resizeEvent(QResizeEvent * /* event */)
    {
    }

    void BlurPicker::mousePressEvent(QMouseEvent *event)
    {
        int delta = 0;
        if(event->x() > (width() / 2))
        {
            delta = 1;
        }
        else
        {
            delta = -1;
        }

        if (m_animation.state() == QAbstractAnimation::Stopped && delta) {
            m_animation.setEndValue(m_index + delta);
            m_animation.start();
            event->accept();
        }
    }