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# renderarea.cpp Example File
painting/basicdrawing/renderarea.cpp

        #include <QtGui>

        #include "renderarea.h"

        RenderArea::RenderArea(QWidget *parent)
            : QWidget(parent)
        {
            shape = Polygon;
            antialiased = false;
            pixmap.load(":/images/qt-logo.png");

            setBackgroundRole(QPalette::Base);
        }

        QSize RenderArea::minimumSizeHint() const
        {
            return QSize(100, 100);
        }

        QSize RenderArea::sizeHint() const
        {
            return QSize(400, 200);
        }

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

        void RenderArea::setPen(const QPen &pen)
        {
            this->pen = pen;
            update();
        }

        void RenderArea::setBrush(const QBrush &brush)
        {
            this->brush = brush;
            update();
        }

        void RenderArea::setAntialiased(bool antialiased)
        {
            this->antialiased = antialiased;
            update();
        }

        void RenderArea::setTransformed(bool transformed)
        {
            this->transformed = transformed;
            update();
        }

        void RenderArea::paintEvent(QPaintEvent *)
        {
            static const int polygonPoints[8] = { 10, 80, 20, 10, 80, 30, 90, 70 };
            QPolygon polygon(4, polygonPoints);

            QRect rect(10, 20, 80, 60);

            QPainterPath path;
            path.moveTo(20, 80);
            path.lineTo(20, 30);
            path.cubicTo(80, 0, 50, 50, 80, 80);

            int startAngle = 30 * 16;
            int arcLength = 120 * 16;

            QPainter painter(this);
            painter.setPen(pen);
            painter.setBrush(brush);
            if (antialiased)
                painter.setRenderHint(QPainter::Antialiasing);

            for (int x = 0; x < width(); x += 100) {
                for (int y = 0; y < height(); y += 100) {
                    painter.save();
                    painter.translate(x, y);
                    if (transformed) {
                        painter.translate(50, 50);
                        painter.rotate(60.0);
                        painter.scale(0.6, 0.9);
                        painter.translate(-50, -50);
                    }

                    switch (shape) {
                    case Line:
                        painter.drawLine(rect.bottomLeft(), rect.topRight());
                        break;
                    case Points:
                        painter.drawPoints(polygon);
                        break;
                    case Polyline:
                        painter.drawPolyline(polygon);
                        break;
                    case Polygon:
                        painter.drawPolygon(polygon);
                        break;
                    case Rect:
                        painter.drawRect(rect);
                        break;
                    case RoundRect:
                        painter.drawRoundRect(rect);
                        break;
                    case Ellipse:
                        painter.drawEllipse(rect);
                        break;
                    case Arc:
                        painter.drawArc(rect, startAngle, arcLength);
                        break;
                    case Chord:
                        painter.drawChord(rect, startAngle, arcLength);
                        break;
                    case Pie:
                        painter.drawPie(rect, startAngle, arcLength);
                        break;
                    case Path:
                        painter.drawPath(path);
                        break;
                    case Text:
                        painter.drawText(rect, Qt::AlignCenter, tr("Qt by\nTrolltech"));
                        break;
                    case Pixmap:
                        painter.drawPixmap(10, 10, pixmap);
                    }
                    painter.restore();
                }
            }
        }