LevelMeter.h

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/*
 * SPDX-FileCopyrightText: 2026 Paolo Sereno <paolomsereno@gmail.com>
 *
 * SPDX-License-Identifier: MIT
 */
 
#pragma once
 
#include <QtIndustrialWidgets/qtindustrialwidgets_global.h>
#include <QtWidgets/QWidget>
#include <QtGui/QColor>
#include <QtCore/QVector>
#include <QtCore/QStringList>
#include <memory>
 
namespace QtIndustrialWidgets {
 
class LevelMeterPrivate;
 
class QTINDUSTRIALWIDGETS_EXPORT LevelMeter : public QWidget
{
    Q_OBJECT
 
    Q_PROPERTY(int channelCount READ channelCount WRITE setChannelCount NOTIFY appearanceChanged)
    Q_PROPERTY(double minimum READ minimum WRITE setMinimum NOTIFY rangeChanged)
    Q_PROPERTY(double maximum READ maximum WRITE setMaximum NOTIFY rangeChanged)
    Q_PROPERTY(double warningThreshold READ warningThreshold WRITE setWarningThreshold NOTIFY appearanceChanged)
    Q_PROPERTY(double errorThreshold READ errorThreshold WRITE setErrorThreshold NOTIFY appearanceChanged)
    Q_PROPERTY(int segmentCount READ segmentCount WRITE setSegmentCount NOTIFY appearanceChanged)
    Q_PROPERTY(DisplayMode displayMode READ displayMode WRITE setDisplayMode NOTIFY appearanceChanged)
    Q_PROPERTY(Qt::Orientation orientation READ orientation WRITE setOrientation NOTIFY appearanceChanged)
    Q_PROPERTY(bool peakHoldEnabled READ isPeakHoldEnabled WRITE setPeakHoldEnabled NOTIFY appearanceChanged)
    Q_PROPERTY(int peakHoldTimeMs READ peakHoldTimeMs WRITE setPeakHoldTimeMs NOTIFY appearanceChanged)
    Q_PROPERTY(double peakDecayRate READ peakDecayRate WRITE setPeakDecayRate NOTIFY appearanceChanged)
    Q_PROPERTY(bool scaleVisible READ isScaleVisible WRITE setScaleVisible NOTIFY appearanceChanged)
    Q_PROPERTY(QString unit READ unit WRITE setUnit NOTIFY appearanceChanged)
    Q_PROPERTY(QString title READ title WRITE setTitle NOTIFY appearanceChanged)
    Q_PROPERTY(QColor normalColor READ normalColor WRITE setNormalColor NOTIFY appearanceChanged)
    Q_PROPERTY(QColor warningColor READ warningColor WRITE setWarningColor NOTIFY appearanceChanged)
    Q_PROPERTY(QColor errorColor READ errorColor WRITE setErrorColor NOTIFY appearanceChanged)
    Q_PROPERTY(QColor peakColor READ peakColor WRITE setPeakColor NOTIFY appearanceChanged)
    Q_PROPERTY(QColor backgroundColor READ backgroundColor WRITE setBackgroundColor NOTIFY appearanceChanged)
    Q_PROPERTY(QColor textColor READ textColor WRITE setTextColor NOTIFY appearanceChanged)
 
public:
    enum class DisplayMode {
        Segmented,  
        Continuous  
    };
    Q_ENUM(DisplayMode)
 
    
    explicit LevelMeter(QWidget *parent = nullptr);
    ~LevelMeter() override;
 
    [[nodiscard]] int channelCount() const;
    [[nodiscard]] double minimum() const;
    [[nodiscard]] double maximum() const;
    [[nodiscard]] double warningThreshold() const;
    [[nodiscard]] double errorThreshold() const;
    [[nodiscard]] int segmentCount() const;
    [[nodiscard]] DisplayMode displayMode() const;
    [[nodiscard]] Qt::Orientation orientation() const;
    [[nodiscard]] bool isPeakHoldEnabled() const;
    [[nodiscard]] int peakHoldTimeMs() const;
    [[nodiscard]] double peakDecayRate() const;
    [[nodiscard]] bool isScaleVisible() const;
    [[nodiscard]] QString unit() const;
    [[nodiscard]] QString title() const;
 
    [[nodiscard]] double value(int channel = 0) const;
    [[nodiscard]] double peakValue(int channel = 0) const;
    [[nodiscard]] QVector<double> values() const;
 
    [[nodiscard]] QStringList channelLabels() const;
 
    [[nodiscard]] QColor normalColor() const;
    [[nodiscard]] QColor warningColor() const;
    [[nodiscard]] QColor errorColor() const;
    [[nodiscard]] QColor peakColor() const;
    [[nodiscard]] QColor backgroundColor() const;
    [[nodiscard]] QColor textColor() const;
 
    [[nodiscard]] QSize sizeHint() const override;
    [[nodiscard]] QSize minimumSizeHint() const override;
 
public Q_SLOTS:
    void setValue(double value);
    void setValue(int channel, double value);
    void setValues(const QVector<double> &values);
    void resetPeaks();
 
    void setChannelCount(int count);
    void setRange(double min, double max);
    void setMinimum(double min);
    void setMaximum(double max);
    void setWarningThreshold(double threshold);
    void setErrorThreshold(double threshold);
    void setSegmentCount(int count);
    void setDisplayMode(DisplayMode mode);
    void setOrientation(Qt::Orientation orientation);
    void setPeakHoldEnabled(bool enabled);
    void setPeakHoldTimeMs(int ms);
    void setPeakDecayRate(double rate);
    void setScaleVisible(bool visible);
    void setUnit(const QString &unit);
    void setTitle(const QString &title);
    void setChannelLabels(const QStringList &labels);
    void setNormalColor(const QColor &color);
    void setWarningColor(const QColor &color);
    void setErrorColor(const QColor &color);
    void setPeakColor(const QColor &color);
    void setBackgroundColor(const QColor &color);
    void setTextColor(const QColor &color);
 
Q_SIGNALS:
    void valueChanged(int channel, double value);
    void overloadOccurred(int channel);
    void rangeChanged(double min, double max);
    void appearanceChanged();
 
protected:
    void paintEvent(QPaintEvent *event) override;
    void resizeEvent(QResizeEvent *event) override;
    void changeEvent(QEvent *event) override;
 
private Q_SLOTS:
    void updatePeakDecay();
 
private:
    void renderStaticBackground();
    void drawChannelBar(QPainter &painter, int chIndex, const QRectF &barRect);
    void drawSegmentedBar(QPainter &painter, double val, double peakVal, const QRectF &barRect);
    void drawContinuousBar(QPainter &painter, double val, double peakVal, const QRectF &barRect);
    QColor colorForNormalizedValue(double norm) const;
    QVector<QRectF> calculateBarRects(const QRectF &contentRect) const;
 
    std::unique_ptr<LevelMeterPrivate> d_ptr;
    Q_DECLARE_PRIVATE(LevelMeter)
};
 
} // namespace QtIndustrialWidgets