renderarea.cpp Example File

  /****************************************************************************
  **
  ** Copyright (C) 2016 The Qt Company Ltd.
  ** Contact: https://www.qt.io/licensing/
  **
  ** This file is part of the examples of the Qt Toolkit.
  **
  ** $QT_BEGIN_LICENSE:BSD$
  ** Commercial License Usage
  ** Licensees holding valid commercial Qt licenses may use this file in
  ** accordance with the commercial license agreement provided with the
  ** Software or, alternatively, in accordance with the terms contained in
  ** a written agreement between you and The Qt Company. For licensing terms
  ** and conditions see https://www.qt.io/terms-conditions. For further
  ** information use the contact form at https://www.qt.io/contact-us.
  **
  ** BSD License Usage
  ** Alternatively, 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 The Qt Company Ltd 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 "renderarea.h"

  #include <QPainter>

  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);

      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\nThe Qt Company"));
                  break;
              case Pixmap:
                  painter.drawPixmap(10, 10, pixmap);
              }
              painter.restore();
          }
      }

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