displaywidget.cpp Example File

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  #include <QtWidgets>
  #include "displaywidget.h"

  DisplayWidget::DisplayWidget(QWidget *parent)
      : QWidget(parent)
  {
      QPainterPath car;
      QPainterPath house;

      QFile file(":resources/shapes.dat");
      file.open(QFile::ReadOnly);
      QDataStream stream(&file);
      stream >> car >> house >> tree >> moon;
      file.close();

      shapeMap[Car] = car;
      shapeMap[House] = house;

      background = Sky;
      shapeColor = Qt::darkYellow;
      shape = House;
  }

  void DisplayWidget::paintEvent(QPaintEvent * /* event */)
  {
      QPainter painter;
      painter.begin(this);
      painter.setRenderHint(QPainter::Antialiasing);
      paint(painter);
      painter.end();
  }

  void DisplayWidget::paint(QPainter &painter)
  {
      painter.setClipRect(QRect(0, 0, 200, 200));
      painter.setPen(Qt::NoPen);

      switch (background) {
      case Sky:
      default:
          painter.fillRect(QRect(0, 0, 200, 200), Qt::darkBlue);
          painter.translate(145, 10);
          painter.setBrush(Qt::white);
          painter.drawPath(moon);
          painter.translate(-145, -10);
          break;
      case Trees:
      {
          painter.fillRect(QRect(0, 0, 200, 200), Qt::darkGreen);
          painter.setBrush(Qt::green);
          painter.setPen(Qt::black);
          for (int y = -55, row = 0; y < 200; y += 50, ++row) {
              int xs;
              if (row == 2 || row == 3)
                  xs = 150;
              else
                  xs = 50;
              for (int x = 0; x < 200; x += xs) {
                  painter.save();
                  painter.translate(x, y);
                  painter.drawPath(tree);
                  painter.restore();
              }
          }
          break;
      }
      case Road:
          painter.fillRect(QRect(0, 0, 200, 200), Qt::gray);
          painter.setPen(QPen(Qt::white, 4, Qt::DashLine));
          painter.drawLine(QLine(0, 35, 200, 35));
          painter.drawLine(QLine(0, 165, 200, 165));
          break;
      }

      painter.setBrush(shapeColor);
      painter.setPen(Qt::black);
      painter.translate(100, 100);
      painter.drawPath(shapeMap[shape]);
  }

  QColor DisplayWidget::color() const
  {
      return shapeColor;
  }

  void DisplayWidget::setBackground(Background background)
  {
      this->background = background;
      update();
  }

  void DisplayWidget::setColor(const QColor &color)
  {
      this->shapeColor = color;
      update();
  }

  void DisplayWidget::setShape(Shape shape)
  {
      this->shape = shape;
      update();
  }