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/****************************************************************************
**
** Copyright (C) 2012 Digia Plc and/or its subsidiary(-ies).
** Contact: http://www.qt-project.org/legal
**
** This file is part of the examples of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** 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 Digia. For licensing terms and
** conditions see http://qt.digia.com/licensing. For further information
** use the contact form at http://qt.digia.com/contact-us.
**
** 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.
**
** In addition, as a special exception, Digia gives you certain additional
** rights. These rights are described in the Digia Qt LGPL Exception
** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
**
** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU
** General Public License version 3.0 as published by the Free Software
** Foundation and appearing in the file LICENSE.GPL included in the
** packaging of this file. Please review the following information to
** ensure the GNU General Public License version 3.0 requirements will be
** met: http://www.gnu.org/copyleft/gpl.html.
**
**
** $QT_END_LICENSE$
**
****************************************************************************/
#include <QtGui>
#include <math.h>
#include "renderthread.h"
//! [0]
RenderThread::RenderThread(QObject *parent)
: QThread(parent)
{
restart = false;
abort = false;
for (int i = 0; i < ColormapSize; ++i)
colormap[i] = rgbFromWaveLength(380.0 + (i * 400.0 / ColormapSize));
}
//! [0]
//! [1]
RenderThread::~RenderThread()
{
mutex.lock();
abort = true;
condition.wakeOne();
mutex.unlock();
wait();
}
//! [1]
//! [2]
void RenderThread::render(double centerX, double centerY, double scaleFactor,
QSize resultSize)
{
QMutexLocker locker(&mutex);
this->centerX = centerX;
this->centerY = centerY;
this->scaleFactor = scaleFactor;
this->resultSize = resultSize;
if (!isRunning()) {
start(LowPriority);
} else {
restart = true;
condition.wakeOne();
}
}
//! [2]
//! [3]
void RenderThread::run()
{
forever {
mutex.lock();
QSize resultSize = this->resultSize;
double scaleFactor = this->scaleFactor;
double centerX = this->centerX;
double centerY = this->centerY;
mutex.unlock();
//! [3]
//! [4]
int halfWidth = resultSize.width() / 2;
//! [4] //! [5]
int halfHeight = resultSize.height() / 2;
QImage image(resultSize, QImage::Format_RGB32);
const int NumPasses = 8;
int pass = 0;
while (pass < NumPasses) {
const int MaxIterations = (1 << (2 * pass + 6)) + 32;
const int Limit = 4;
bool allBlack = true;
for (int y = -halfHeight; y < halfHeight; ++y) {
if (restart)
break;
if (abort)
return;
uint *scanLine =
reinterpret_cast<uint *>(image.scanLine(y + halfHeight));
double ay = centerY + (y * scaleFactor);
for (int x = -halfWidth; x < halfWidth; ++x) {
double ax = centerX + (x * scaleFactor);
double a1 = ax;
double b1 = ay;
int numIterations = 0;
do {
++numIterations;
double a2 = (a1 * a1) - (b1 * b1) + ax;
double b2 = (2 * a1 * b1) + ay;
if ((a2 * a2) + (b2 * b2) > Limit)
break;
++numIterations;
a1 = (a2 * a2) - (b2 * b2) + ax;
b1 = (2 * a2 * b2) + ay;
if ((a1 * a1) + (b1 * b1) > Limit)
break;
} while (numIterations < MaxIterations);
if (numIterations < MaxIterations) {
*scanLine++ = colormap[numIterations % ColormapSize];
allBlack = false;
} else {
*scanLine++ = qRgb(0, 0, 0);
}
}
}
if (allBlack && pass == 0) {
pass = 4;
} else {
if (!restart)
emit renderedImage(image, scaleFactor);
//! [5] //! [6]
++pass;
}
//! [6] //! [7]
}
//! [7]
//! [8]
mutex.lock();
//! [8] //! [9]
if (!restart)
condition.wait(&mutex);
restart = false;
mutex.unlock();
}
}
//! [9]
//! [10]
uint RenderThread::rgbFromWaveLength(double wave)
{
double r = 0.0;
double g = 0.0;
double b = 0.0;
if (wave >= 380.0 && wave <= 440.0) {
r = -1.0 * (wave - 440.0) / (440.0 - 380.0);
b = 1.0;
} else if (wave >= 440.0 && wave <= 490.0) {
g = (wave - 440.0) / (490.0 - 440.0);
b = 1.0;
} else if (wave >= 490.0 && wave <= 510.0) {
g = 1.0;
b = -1.0 * (wave - 510.0) / (510.0 - 490.0);
} else if (wave >= 510.0 && wave <= 580.0) {
r = (wave - 510.0) / (580.0 - 510.0);
g = 1.0;
} else if (wave >= 580.0 && wave <= 645.0) {
r = 1.0;
g = -1.0 * (wave - 645.0) / (645.0 - 580.0);
} else if (wave >= 645.0 && wave <= 780.0) {
r = 1.0;
}
double s = 1.0;
if (wave > 700.0)
s = 0.3 + 0.7 * (780.0 - wave) / (780.0 - 700.0);
else if (wave < 420.0)
s = 0.3 + 0.7 * (wave - 380.0) / (420.0 - 380.0);
r = pow(r * s, 0.8);
g = pow(g * s, 0.8);
b = pow(b * s, 0.8);
return qRgb(int(r * 255), int(g * 255), int(b * 255));
}
//! [10]
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