starrating.cpp Example File

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 #include <QtWidgets>
 #include <math.h>

 #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 * cos(0.8 * i * 3.14),
                                0.5 + 0.5 * 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();
 }