Qt 5.6 | Qt Widgets | Star Delegate Example | starrating.cpp Example File

Qt 5.6.2 Reference Documentation

# starrating.cpp Example File

itemviews/stardelegate/starrating.cpp

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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();
      }