Qt Reference Documentation

# displaywidget.cpp Example File

painting/svggenerator/displaywidget.cpp

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     #include <QtGui>
     #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();
     }