AudioProcessorParameterSlider for JUCE

AudioProcessorParameterSlider.cpp

#include "AudioProcessorParameterSlider.h"

using namespace juce;

AudioProcessorParameterSlider::AudioProcessorParameterSlider()
{
    initParameter(nullptr);
}

AudioProcessorParameterSlider::AudioProcessorParameterSlider (const AudioProcessorParameter* p)
{
    initParameter(p);
}

AudioProcessorParameterSlider::AudioProcessorParameterSlider (const String &componentName):
Slider (componentName)
{
    initParameter(nullptr);
}

void AudioProcessorParameterSlider::initParameter (const AudioProcessorParameter* p)
{
    parameter = p;
    textSuffixEnabled = true;
}

void AudioProcessorParameterSlider::setTextSuffixEnabled (bool v)
{
    textSuffixEnabled = v;
}

const AudioProcessorParameter* AudioProcessorParameterSlider::getParameter()
{
    jassert (parameter != nullptr);
    return parameter;
}

void AudioProcessorParameterSlider::setParameter (const AudioProcessorParameter* p)
{
    if (parameter == p)
        return;
    parameter = p;
    // Repaint because text may change.
    updateText();
    repaint();
}

#if JUCE_COMPILER_SUPPORTS_LAMBDAS || defined (DOXYGEN)
// wraps SliderAttachment to link with the slider
AudioProcessorParameterSlider::SliderAttachment::SliderAttachment (AudioProcessorValueTreeState& stateToControl, const String& parameterID, AudioProcessorParameterSlider& sliderToControl)
: AudioProcessorValueTreeState::SliderAttachment (stateToControl, parameterID, sliderToControl)
{
    sliderToControl.setParameter(stateToControl.getParameter(parameterID));
}
#endif

String AudioProcessorParameterSlider::getTextFromValue (double value)
{
    if (parameter == nullptr)
        return Slider::getTextFromValue (value);

    // juce::AudioProcessorValueTreeState::SliderAttachment sets the slider minimum and maximum to custom values.
    // We map the range to a 0 to 1 range.
    const NormalisableRange<double> range (getMinimum(), getMaximum());
    const float normalizedVal = (float) range.convertTo0to1 (value);

    String result = parameter->getText (normalizedVal, getNumDecimalPlacesToDisplay());
    if (! textSuffixEnabled)
    {
        String label = parameter->getLabel();
        if (! label.isEmpty() && result.endsWithIgnoreCase (parameter->getLabel()))
        {
            result = result.dropLastCharacters (label.length());
            result.trimEnd();
        }
    }
    return result;
}

double AudioProcessorParameterSlider::getValueFromText (const String& text)
{
    if (parameter == nullptr)
        return Slider::getValueFromText (text);
    return parameter->getValueForText (text);
}

AudioProcessorParameterSlider.h

#ifndef AUDIOPROCESSORPARAMETERSLIDER_H_INCLUDED
#define AUDIOPROCESSORPARAMETERSLIDER_H_INCLUDED

#include "JuceHeader.h"
#include <assert.h>

// A Slider for an audio plugin parameter that has
// * The same mapping of proportion-of-length to value as the parameter (same as automation).
// * The same text formatting as the parameter.
//
// Internally the value for the Slider is the parameter value in 0 to 1 range,
// but due to the text formatting it looks like user-readable values.

class AudioProcessorParameterSlider : public juce::Slider
{
public:
    AudioProcessorParameterSlider();
    AudioProcessorParameterSlider(const juce::String &componentName);
    AudioProcessorParameterSlider(const juce::AudioProcessorParameter*);
    const juce::AudioProcessorParameter* getParameter();
    void setParameter (const juce::AudioProcessorParameter*);
    void setTextSuffixEnabled (bool);

#if JUCE_COMPILER_SUPPORTS_LAMBDAS || defined (DOXYGEN)
    // SliderAttachment
    class SliderAttachment : public juce::AudioProcessorValueTreeState::SliderAttachment
    {
    public:
        SliderAttachment (juce::AudioProcessorValueTreeState& stateToControl,
                          const juce::String& parameterID,
                          AudioProcessorParameterSlider& sliderToControl);
        virtual ~SliderAttachment() = default;
    };
#endif

    juce::String getTextFromValue (double value) override;
    double getValueFromText (const juce::String& text) override;

protected:
    const juce::AudioProcessorParameter* parameter;

private:
    void initParameter(const juce::AudioProcessorParameter*);

    bool textSuffixEnabled;
};

#endif // AUDIOPROCESSORPARAMETERSLIDER_H_INCLUDED