Qt 4.6: renderarea.cpp Example File (painting/basicdrawing/renderarea.cpp)

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

     /****************************************************************************
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     ** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
     ** Contact: Nokia Corporation (qt-info@nokia.com)
     **
     ** This file is part of the examples of the Qt Toolkit.
     **
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     ** No Commercial Usage
     ** This file contains pre-release code and may not be distributed.
     ** You may use this file in accordance with the terms and conditions
     ** contained in the Technology Preview License Agreement accompanying
     ** this package.
     **
     ** GNU Lesser General Public License Usage
     ** Alternatively, this file may be used under the terms of the GNU Lesser
     ** General Public License version 2.1 as published by the Free Software
     ** Foundation and appearing in the file LICENSE.LGPL included in the
     ** packaging of this file.  Please review the following information to
     ** ensure the GNU Lesser General Public License version 2.1 requirements
     ** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
     **
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     ** additional rights.  These rights are described in the Nokia Qt LGPL
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     ** package.
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     ****************************************************************************/

     #include <QtGui>

     #include "renderarea.h"

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

         setBackgroundRole(QPalette::Base);
         setAutoFillBackground(true);
     }

     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 * /* event */)
     {
         static const QPoint points[4] = {
             QPoint(10, 80),
             QPoint(20, 10),
             QPoint(80, 30),
             QPoint(90, 70)
         };

         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 = 20 * 16;
         int arcLength = 120 * 16;

         QPainter painter(this);
         painter.setPen(pen);
         painter.setBrush(brush);
         if (antialiased) {
             painter.setRenderHint(QPainter::Antialiasing, true);
             painter.translate(+0.5, +0.5);
         }

         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(points, 4);
                     break;
                 case Polyline:
                     painter.drawPolyline(points, 4);
                     break;
                 case Polygon:
                     painter.drawPolygon(points, 4);
                     break;
                 case Rect:
                     painter.drawRect(rect);
                     break;
                 case RoundedRect:
                     painter.drawRoundedRect(rect, 25, 25, Qt::RelativeSize);
                     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\nNokia"));
                     break;
                 case Pixmap:
                     painter.drawPixmap(10, 10, pixmap);
                 }
                 painter.restore();
             }
         }

         painter.setPen(palette().dark().color());
         painter.setBrush(Qt::NoBrush);
         painter.drawRect(QRect(0, 0, width() - 1, height() - 1));
     }