LevelMeter Class Reference

#include <levelmeter.h>

Inheritance diagram for LevelMeter:

Collaboration diagram for LevelMeter:

Public Slots
void	reset ()
void	levelChanged (qreal rmsLevel, qreal peakLevel, int numSamples)

Public Member Functions
	LevelMeter (QWidget *parent=0)
virtual	~LevelMeter ()
void	paintEvent (QPaintEvent *event)
void	resizeEvent (QResizeEvent *event)
void	setAverageSmoothing (uint32_t smoothingFactor)

Protected Slots
void	redrawTimerExpired ()

Protected Member Functions
virtual void	render (QPainter *painter)=0
virtual void	resized ()=0
int	shiftx (int val, int width)

Protected Attributes
qreal	m_avgLevel
qreal	m_peakLevel
qreal	m_decayedPeakLevel
QTime	m_peakLevelChanged
qreal	m_peakDecayRate
qreal	m_peakHoldLevel
QTime	m_peakHoldLevelChanged
uint32_t	m_avgSmoothing
QTimer *	m_redrawTimer
QColor	m_avgColor
QColor	m_peakColor
QColor	m_decayedPeakColor
ScaleEngine	m_scaleEngine
QPixmap *	m_backgroundPixmap

Detailed Description

Widget which displays a vertical audio level meter, indicating the RMS and peak levels of the window of audio samples most recently analyzed by the Engine.

Definition at line 62 of file levelmeter.h.

Constructor & Destructor Documentation

LevelMeter()

LevelMeter::LevelMeter

(

QWidget *

parent = 0

)

Definition at line 60 of file levelmeter.cpp.

References m_redrawTimer, RedrawInterval, and redrawTimerExpired().

    :   QWidget(parent)
    ,   m_avgLevel(0.0)
    ,   m_peakLevel(0.0)
    ,   m_decayedPeakLevel(0.0)
    ,   m_peakDecayRate(PeakDecayRate)
    ,   m_peakHoldLevel(0.0)
    ,   m_avgSmoothing(256)
    ,   m_redrawTimer(new QTimer(this))
    ,   m_avgColor(0xff, 0x8b, 0x00, 128)          // color mapper foreground
    ,   m_peakColor(Qt::red)                       // just red 100% opaque
    ,   m_decayedPeakColor(0x97, 0x54, 0x00, 128)  // color mapper 59%
    ,   m_backgroundPixmap(0)
{
    setSizePolicy(QSizePolicy::Fixed, QSizePolicy::Preferred);
    setMinimumWidth(30);

    connect(m_redrawTimer, SIGNAL(timeout()), this, SLOT(redrawTimerExpired()));
    m_redrawTimer->start(RedrawInterval);
}

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~LevelMeter()

LevelMeter::~LevelMeter ( )

virtual

Definition at line 81 of file levelmeter.cpp.

References m_backgroundPixmap.

{
    if (m_backgroundPixmap) {
        delete m_backgroundPixmap;
    }
}

Member Function Documentation

levelChanged

void LevelMeter::levelChanged ( qreal  rmsLevel, qreal  peakLevel, int  numSamples  )

slot

Definition at line 95 of file levelmeter.cpp.

References m_avgLevel, m_avgSmoothing, m_decayedPeakLevel, m_peakHoldLevel, m_peakHoldLevelChanged, m_peakLevel, and m_peakLevelChanged.

{
    // Smooth the RMS signal
    const qreal smooth = pow(qreal(0.9), static_cast<qreal>(numSamples) / m_avgSmoothing);
    m_avgLevel = (m_avgLevel * smooth) + (avgLevel * (1.0 - smooth));

    if (peakLevel > m_decayedPeakLevel) {
        m_peakLevel = peakLevel;
        m_decayedPeakLevel = peakLevel;
        m_peakLevelChanged.start();
    }

    if (peakLevel > m_peakHoldLevel) {
        m_peakHoldLevel = peakLevel;
        m_peakHoldLevelChanged.start();
    }

    update();
}

paintEvent()

void LevelMeter::paintEvent

(

QPaintEvent *

event

)

Definition at line 132 of file levelmeter.cpp.

References render().

{
    Q_UNUSED(event)

    QPainter painter(this);
    render(&painter);
}

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redrawTimerExpired

void LevelMeter::redrawTimerExpired ( )

protectedslot

Definition at line 115 of file levelmeter.cpp.

References m_decayedPeakLevel, m_peakDecayRate, m_peakHoldLevel, m_peakHoldLevelChanged, m_peakLevel, m_peakLevelChanged, and PeakHoldLevelDuration.

Referenced by LevelMeter().

{
    // Decay the peak signal
    const int elapsedMs = m_peakLevelChanged.elapsed();
    const qreal decayAmount = m_peakDecayRate * elapsedMs;
    if (decayAmount < m_peakLevel)
        m_decayedPeakLevel = m_peakLevel - decayAmount;
    else
        m_decayedPeakLevel = 0.0;

    // Check whether to clear the peak hold level
    if (m_peakHoldLevelChanged.elapsed() > PeakHoldLevelDuration)
        m_peakHoldLevel = 0.0;

    update();
}

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render()

virtual void LevelMeter::render ( QPainter *  painter )

protectedpure virtual

Implemented in LevelMeterSignalDB, and LevelMeterVU.

Referenced by paintEvent().

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reset

void LevelMeter::reset ( )

slot

Definition at line 88 of file levelmeter.cpp.

References m_avgLevel, and m_peakLevel.

{
    m_avgLevel = 0.0;
    m_peakLevel = 0.0;
    update();
}

resized()

virtual void LevelMeter::resized ( )

protectedpure virtual

Implemented in LevelMeterSignalDB, and LevelMeterVU.

Referenced by resizeEvent().

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resizeEvent()

void LevelMeter::resizeEvent

(

QResizeEvent *

event

)

Definition at line 140 of file levelmeter.cpp.

References resized().

{
    Q_UNUSED(event)

    resized();
}

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setAverageSmoothing()

void LevelMeter::setAverageSmoothing

(

uint32_t

smoothingFactor

)

Definition at line 147 of file levelmeter.cpp.

References m_avgSmoothing.

{
    m_avgSmoothing = smoothingFactor < 1 ? 1 : smoothingFactor > 256 ? 256 : smoothingFactor;
}

shiftx()

int LevelMeter::shiftx ( int  val, int  width  )

inlineprotected

Shift the x coordinate so it does not fall right on 0 or width-1

Definition at line 142 of file levelmeter.h.

Referenced by LevelMeterVU::resized(), and LevelMeterSignalDB::resized().

    {
        return val == 0 ? 1 : val == width-1 ? width-2 : val;
    }

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Member Data Documentation

m_avgColor

QColor LevelMeter::m_avgColor

protected

Definition at line 131 of file levelmeter.h.

Referenced by LevelMeterVU::render().

m_avgLevel

qreal LevelMeter::m_avgLevel

protected

Height of RMS level bar. Range 0.0 - 1.0.

Definition at line 87 of file levelmeter.h.

Referenced by levelChanged(), LevelMeterVU::render(), LevelMeterSignalDB::render(), and reset().

m_avgSmoothing

uint32_t LevelMeter::m_avgSmoothing

protected

Average smoothing factor (between 1: fast and 256: slow)

Definition at line 127 of file levelmeter.h.

Referenced by levelChanged(), and setAverageSmoothing().

m_backgroundPixmap

QPixmap* LevelMeter::m_backgroundPixmap

protected

Definition at line 136 of file levelmeter.h.

Referenced by LevelMeterVU::render(), LevelMeterSignalDB::render(), LevelMeterVU::resized(), LevelMeterSignalDB::resized(), and ~LevelMeter().

m_decayedPeakColor

QColor LevelMeter::m_decayedPeakColor

protected

Definition at line 133 of file levelmeter.h.

Referenced by LevelMeterVU::render().

m_decayedPeakLevel

qreal LevelMeter::m_decayedPeakLevel

protected

Height of peak level bar. This is calculated by decaying m_peakLevel depending on the elapsed time since m_peakLevelChanged, and the value of m_decayRate.

Definition at line 100 of file levelmeter.h.

Referenced by levelChanged(), redrawTimerExpired(), LevelMeterVU::render(), and LevelMeterSignalDB::render().

m_peakColor

QColor LevelMeter::m_peakColor

protected

Definition at line 132 of file levelmeter.h.

Referenced by LevelMeterVU::render().

m_peakDecayRate

qreal LevelMeter::m_peakDecayRate

protected

Rate at which peak level bar decays. Expressed in level units / millisecond.

Definition at line 111 of file levelmeter.h.

Referenced by redrawTimerExpired().

m_peakHoldLevel

qreal LevelMeter::m_peakHoldLevel

protected

High watermark of peak level. Range 0.0 - 1.0.

Definition at line 117 of file levelmeter.h.

Referenced by levelChanged(), redrawTimerExpired(), LevelMeterVU::render(), and LevelMeterSignalDB::render().

m_peakHoldLevelChanged

QTime LevelMeter::m_peakHoldLevelChanged

protected

Time at which m_peakHoldLevel was last changed.

Definition at line 122 of file levelmeter.h.

Referenced by levelChanged(), and redrawTimerExpired().

m_peakLevel

qreal LevelMeter::m_peakLevel

protected

Most recent peak level. Range 0.0 - 1.0.

Definition at line 93 of file levelmeter.h.

Referenced by levelChanged(), redrawTimerExpired(), and reset().

m_peakLevelChanged

QTime LevelMeter::m_peakLevelChanged

protected

Time at which m_peakLevel was last changed.

Definition at line 105 of file levelmeter.h.

Referenced by levelChanged(), and redrawTimerExpired().

m_redrawTimer

QTimer* LevelMeter::m_redrawTimer

protected

Definition at line 129 of file levelmeter.h.

Referenced by LevelMeter().

m_scaleEngine

ScaleEngine LevelMeter::m_scaleEngine

protected

Definition at line 135 of file levelmeter.h.

Referenced by LevelMeterSignalDB::LevelMeterSignalDB(), LevelMeterVU::LevelMeterVU(), LevelMeterVU::resized(), LevelMeterSignalDB::resized(), and LevelMeterSignalDB::setRange().

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The documentation for this class was generated from the following files:

• sdrgui/gui/levelmeter.h
• sdrgui/gui/levelmeter.cpp