starrating.cpp Example File

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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();
  }