- Qt 5.5
- Qt Widgets
- Star Delegate Example
- starrating.cpp Example File
- Qt 5.5.1 Reference Documentation

# starrating.cpp Example File

itemviews/stardelegate/starrating.cpp

    /****************************************************************************
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    ** This file is part of the examples of the Qt Toolkit.
    **
    ** $QT_BEGIN_LICENSE:BSD$
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    #include <QtWidgets>
    #include <cmath>

    #include "starrating.h"

    const int PaintingScaleFactor = 20;

    StarRating::StarRating(int starCount, int maxStarCount)
    {
        myStarCount = starCount;
        myMaxStarCount = maxStarCount;

        starPolygon << QPointF(1.0, 0.5);
        for (int i = 1; i < 5; ++i)
            starPolygon << QPointF(0.5 + 0.5 * std::cos(0.8 * i * 3.14),
                                   0.5 + 0.5 * std::sin(0.8 * i * 3.14));

        diamondPolygon << QPointF(0.4, 0.5) << QPointF(0.5, 0.4)
                       << QPointF(0.6, 0.5) << QPointF(0.5, 0.6)
                       << QPointF(0.4, 0.5);
    }

    QSize StarRating::sizeHint() const
    {
        return PaintingScaleFactor * QSize(myMaxStarCount, 1);
    }

    void StarRating::paint(QPainter *painter, const QRect &rect,
                           const QPalette &palette, EditMode mode) const
    {
        painter->save();

        painter->setRenderHint(QPainter::Antialiasing, true);
        painter->setPen(Qt::NoPen);

        if (mode == Editable) {
            painter->setBrush(palette.highlight());
        } else {
            painter->setBrush(palette.foreground());
        }

        int yOffset = (rect.height() - PaintingScaleFactor) / 2;
        painter->translate(rect.x(), rect.y() + yOffset);
        painter->scale(PaintingScaleFactor, PaintingScaleFactor);

        for (int i = 0; i < myMaxStarCount; ++i) {
            if (i < myStarCount) {
                painter->drawPolygon(starPolygon, Qt::WindingFill);
            } else if (mode == Editable) {
                painter->drawPolygon(diamondPolygon, Qt::WindingFill);
            }
            painter->translate(1.0, 0.0);
        }

        painter->restore();
    }