renderthread.cpp Example File

 /****************************************************************************
 **
 ** Copyright (C) 2015 The Qt Company Ltd.
 ** Contact: http://www.qt.io/licensing/
 **
 ** 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 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();
 }