Qt Reference Documentation

# renderarea.cpp Example File

painting/transformations/renderarea.cpp

     /****************************************************************************
     **
     ** Copyright (C) 2012 Nokia Corporation and/or its subsidiary(-ies).
     ** All rights reserved.
     ** Contact: Nokia Corporation (qt-info@nokia.com)
     **
     ** This file is part of the examples of the Qt Toolkit.
     **
     ** $QT_BEGIN_LICENSE:BSD$
     ** You may use this file under the terms of the BSD license as follows:
     **
     ** "Redistribution and use in source and binary forms, with or without
     ** modification, are permitted provided that the following conditions are
     ** met:
     **   * Redistributions of source code must retain the above copyright
     **     notice, this list of conditions and the following disclaimer.
     **   * Redistributions in binary form must reproduce the above copyright
     **     notice, this list of conditions and the following disclaimer in
     **     the documentation and/or other materials provided with the
     **     distribution.
     **   * Neither the name of Nokia Corporation and its Subsidiary(-ies) nor
     **     the names of its contributors may be used to endorse or promote
     **     products derived from this software without specific prior written
     **     permission.
     **
     ** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     ** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     ** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
     ** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
     ** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     ** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
     ** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     ** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     ** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     ** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     ** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
     ** $QT_END_LICENSE$
     **
     ****************************************************************************/

     #include <QtGui>

     #include "renderarea.h"

     RenderArea::RenderArea(QWidget *parent)
         : QWidget(parent)
     {
         QFont newFont = font();
         newFont.setPixelSize(12);
         setFont(newFont);

         QFontMetrics fontMetrics(newFont);
         xBoundingRect = fontMetrics.boundingRect(tr("x"));
         yBoundingRect = fontMetrics.boundingRect(tr("y"));
     }

     void RenderArea::setOperations(const QList<Operation> &operations)
     {
         this->operations = operations;
         update();
     }

     void RenderArea::setShape(const QPainterPath &shape)
     {
         this->shape = shape;
         update();
     }

     QSize RenderArea::minimumSizeHint() const
     {
         return QSize(182, 182);
     }

     QSize RenderArea::sizeHint() const
     {
         return QSize(232, 232);
     }

     void RenderArea::paintEvent(QPaintEvent *event)
     {
         QPainter painter(this);
         painter.setRenderHint(QPainter::Antialiasing);
         painter.fillRect(event->rect(), QBrush(Qt::white));

         painter.translate(66, 66);

         painter.save();
         transformPainter(painter);
         drawShape(painter);
         painter.restore();

         drawOutline(painter);

         transformPainter(painter);
         drawCoordinates(painter);
     }

     void RenderArea::drawCoordinates(QPainter &painter)
     {
         painter.setPen(Qt::red);

         painter.drawLine(0, 0, 50, 0);
         painter.drawLine(48, -2, 50, 0);
         painter.drawLine(48, 2, 50, 0);
         painter.drawText(60 - xBoundingRect.width() / 2,
                          0 + xBoundingRect.height() / 2, tr("x"));

         painter.drawLine(0, 0, 0, 50);
         painter.drawLine(-2, 48, 0, 50);
         painter.drawLine(2, 48, 0, 50);
         painter.drawText(0 - yBoundingRect.width() / 2,
                          60 + yBoundingRect.height() / 2, tr("y"));
     }

     void RenderArea::drawOutline(QPainter &painter)
     {
         painter.setPen(Qt::darkGreen);
         painter.setPen(Qt::DashLine);
         painter.setBrush(Qt::NoBrush);
         painter.drawRect(0, 0, 100, 100);
     }

     void RenderArea::drawShape(QPainter &painter)
     {
         painter.fillPath(shape, Qt::blue);
     }

     void RenderArea::transformPainter(QPainter &painter)
     {
         for (int i = 0; i < operations.size(); ++i) {
             switch (operations[i]) {
             case Translate:
                 painter.translate(50, 50);
                 break;
             case Scale:
                 painter.scale(0.75, 0.75);
                 break;
             case Rotate:
                 painter.rotate(60);
                 break;
             case NoTransformation:
             default:
                 ;
             }
         }
     }