renderthread.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 "renderthread.h"

  RenderThread::RenderThread(QObject *parent)
      : QThread(parent)
  {
      m_abort = false;
  }

  RenderThread::~RenderThread()
  {
      mutex.lock();
      m_abort = true;
      mutex.unlock();

      wait();
  }

  void RenderThread::processImage(const QImage &image)
  {
      if (image.isNull())
          return;

      m_image = image;
      m_abort = false;
      start();
  }

  void RenderThread::run()
  {
      int size = qMax(m_image.width()/20, m_image.height()/20);
      for (int s = size; s > 0; --s) {
          for (int c = 0; c < 400; ++c) {
              int x1 = qMax(0, (qrand() % m_image.width()) - s/2);
              int x2 = qMin(x1 + s/2 + 1, m_image.width());
              int y1 = qMax(0, (qrand() % m_image.height()) - s/2);
              int y2 = qMin(y1 + s/2 + 1, m_image.height());
              int n = 0;
              int red = 0;
              int green = 0;
              int blue = 0;
              for (int i = y1; i < y2; ++i) {
                  for (int j = x1; j < x2; ++j) {
                      QRgb pixel = m_image.pixel(j, i);
                      red += qRed(pixel);
                      green += qGreen(pixel);
                      blue += qBlue(pixel);
                      n += 1;
                  }
              }
              Block block(QRect(x1, y1, x2 - x1 + 1, y2 - y1 + 1),
                          QColor(red/n, green/n, blue/n));
              emit sendBlock(block);
              if (m_abort)
                  return;
              msleep(10);
          }
      }
  }

  void RenderThread::stopProcess()
  {
      mutex.lock();
      m_abort = true;
      mutex.unlock();
  }