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/*****************************************************************************
* Copyright (C) 2021 the VideoLAN team
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
*****************************************************************************/
#include <QImage>
#include <QColor>
#include "imageluminanceextractor.hpp"
ImageLuminanceExtractor::ImageLuminanceExtractor(QObject *parent) : QObject(parent) {}
QUrl ImageLuminanceExtractor::source() const
{
return m_source;
}
int ImageLuminanceExtractor::luminance() const
{
return m_luminance;
}
bool ImageLuminanceExtractor::isEnabled() const
{
return m_enabled;
}
void ImageLuminanceExtractor::setLuminance(const int luminance)
{
m_luminance = luminance;
emit luminanceChanged(m_luminance);
}
void ImageLuminanceExtractor::setSource(const QUrl &source)
{
if (m_source == source)
return;
m_source = source;
if (m_enabled)
startTask();
else
m_pendingUpdate = true;
emit sourceChanged(m_source);
}
void ImageLuminanceExtractor::setIsEnabled(const bool enabled)
{
if (m_enabled == enabled)
return;
m_enabled = enabled;
if (m_enabled && m_pendingUpdate)
startTask();
emit enabledChanged(m_enabled);
}
void ImageLuminanceExtractor::startTask()
{
m_pendingUpdate = false;
m_task.reset(new LuminanceCalculator(m_source));
connect(m_task.get(), &LuminanceCalculator::result, this, [this]()
{
LuminanceCalculator *task = static_cast<LuminanceCalculator *>(sender());
assert(task == m_task.get());
int result = task->takeResult();
if (result != Status::FAILED)
setLuminance(result);
else
qWarning("luminance extraction failed");
m_task.reset();
});
m_task->start(*QThreadPool::globalInstance());
}
ImageLuminanceExtractor::LuminanceCalculator::LuminanceCalculator(const QUrl &source) : m_source {source} {}
int ImageLuminanceExtractor::LuminanceCalculator::execute()
{
QString path = m_source.isLocalFile() ? m_source.toLocalFile() : m_source.toString();
if (path.startsWith("qrc:///"))
path.replace(0, strlen("qrc:///"), ":/");
else if (!m_source.isLocalFile())
return Status::FAILED;
const QImage image = QImage(path).scaled(128, 128, Qt::KeepAspectRatio);
if (image.isNull())
return Status::FAILED;
int lumimance = 0;
size_t count = 0;
for (int i = 0; i < image.width(); i++)
{
for (int j = 0; j < image.height(); j++)
{
const QColor pixelColor = image.pixelColor(i, j);
if (!pixelColor.isValid())
continue;
lumimance += 0.299*pixelColor.red() + 0.587*pixelColor.green() + 0.144*pixelColor.blue();
count++;
}
}
lumimance = (lumimance / count);
return lumimance;
}