JUCE/modules/juce_audio_processors/utilities/juce_RangedAudioParameter.h

/*
  ==============================================================================

   This file is part of the JUCE library.
   Copyright (c) 2017 - ROLI Ltd.

   JUCE is an open source library subject to commercial or open-source
   licensing.

   By using JUCE, you agree to the terms of both the JUCE 5 End-User License
   Agreement and JUCE 5 Privacy Policy (both updated and effective as of the
   27th April 2017).

   End User License Agreement: www.juce.com/juce-5-licence
   Privacy Policy: www.juce.com/juce-5-privacy-policy

   Or: You may also use this code under the terms of the GPL v3 (see
   www.gnu.org/licenses).

   JUCE IS PROVIDED "AS IS" WITHOUT ANY WARRANTY, AND ALL WARRANTIES, WHETHER
   EXPRESSED OR IMPLIED, INCLUDING MERCHANTABILITY AND FITNESS FOR PURPOSE, ARE
   DISCLAIMED.

  ==============================================================================
*/

namespace juce
{

/**
    This abstract base class is used by some AudioProcessorParameter helper classes.

    @see AudioParameterFloat, AudioParameterInt, AudioParameterBool, AudioParameterChoice

    @tags{Audio}
*/
class JUCE_API RangedAudioParameter   : public AudioProcessorParameterWithID
{
public:
    /** The creation of this object requires providing a name and ID which will be
        constant for its lifetime.
    */
    RangedAudioParameter (const String& parameterID,
                          const String& name,
                          const String& label = {},
                          Category category = AudioProcessorParameter::genericParameter)
        : AudioProcessorParameterWithID (parameterID, name, label, category) {}

    /** Returns the range of values that the parameter can take. */
    virtual const NormalisableRange<float>& getNormalisableRange() const = 0;

    /** Returns the number of steps for this parameter based on the normalisable range's interval.
        If you are using lambda functions to define the normalisable range's snapping behaviour
        then you should override this function so that it returns the number of snapping points.
    */
    int getNumSteps() const override
    {
        const auto& range = getNormalisableRange();

        if (range.interval > 0)
            return (static_cast<int> ((range.end - range.start) / range.interval) + 1);

        return AudioProcessor::getDefaultNumParameterSteps();
    }

    /** Normalises and snaps a value based on the normalisable range. */
    float convertTo0to1 (float v) const noexcept
    {
        const auto& range = getNormalisableRange();
        return range.convertTo0to1 (range.snapToLegalValue (v));
    }

    /** Denormalises and snaps a value based on the normalisable range. */
    float convertFrom0to1 (float v) const noexcept
    {
        const auto& range = getNormalisableRange();
        return range.snapToLegalValue (range.convertFrom0to1 (jlimit (0.0f, 1.0f, v)));
    }
};

} // namespace juce