levelmeter.cpp

// SPDX-FileCopyrightText: Copyright (C) 2015 swift Project Community / Contributors
// SPDX-License-Identifier: GPL-3.0-or-later OR LicenseRef-swift-pilot-client-1
// Class based on qt example: Copyright (C) 2012 Nokia Corporation and/or its subsidiary(-ies)
 
#include "gui/levelmeter.h"
 
#include <QPainter>
#include <QRect>
#include <QSizePolicy>
#include <QTimer>
#include <Qt>
#include <QtGlobal>
 
namespace swift::gui
{
    CLevelMeter::CLevelMeter(QWidget *parent)
        : QFrame(parent), m_redrawTimer(new QTimer(this)), m_lowColor(Qt::gray), m_highColor(Qt::green),
          m_peakColor(255, 200, 200, 255)
    {
        this->setSizePolicy(QSizePolicy::Fixed, QSizePolicy::Preferred);
        this->setMinimumWidth(30);
 
        connect(m_redrawTimer, &QTimer::timeout, this, &CLevelMeter::redrawTimerExpired);
        m_redrawTimer->start(RedrawInterval);
        m_redrawTimer->setObjectName("CLevelMeter");
    }
 
    CLevelMeter::~CLevelMeter() {}
 
    void CLevelMeter::reset()
    {
        m_level = 0.0;
        m_peakLevel = 0.0;
        this->update();
    }
 
    void CLevelMeter::levelChanged(double level)
    {
        m_level = level;
        if (level > m_peakLevel)
        {
            m_peakLevel = level;
            m_peakLevelChanged.start();
        }
    }
 
    void CLevelMeter::redrawTimerExpired()
    {
        // decay
        if (m_peakLevelChanged.elapsed() > PeakHoldLevelDuration)
        {
            m_peakLevel -= DecayValue;
            if (m_peakLevel < m_level || m_peakLevel < 0) { m_peakLevel = 0.0; }
        }
        this->update();
    }
 
    void CLevelMeter::paintEvent(QPaintEvent *event)
    {
        Q_UNUSED(event)
 
        QPainter painter(this);
        QRect bar = this->contentsRect();
        painter.fillRect(bar, Qt::transparent);
        const int w = bar.width();
        const int left = rect().left();
        const int level = qRound(m_level * w);
 
        bar.setLeft(left);
        bar.setRight(level);
        painter.fillRect(bar, m_peakLevel >= High ? m_highColor : m_lowColor);
 
        if (m_peakLevel > m_level)
        {
            const int peak = qRound(m_peakLevel * w);
            bar.setLeft(level);
            bar.setRight(peak);
            painter.fillRect(bar, m_peakColor);
        }
    }
 
} // namespace swift::gui