JUCE/modules/juce_audio_processors/utilities/juce_AudioParameterChoice.h

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

   This file is part of the JUCE 6 technical preview.
   Copyright (c) 2020 - Raw Material Software Limited

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

   For this technical preview, this file is not subject to commercial licensing.

   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
{

/**
    Provides a class of AudioProcessorParameter that can be used to select
    an indexed, named choice from a list.

    @see AudioParameterFloat, AudioParameterInt, AudioParameterBool

    @tags{Audio}
*/
class JUCE_API  AudioParameterChoice  : public RangedAudioParameter
{
public:
    /** Creates a AudioParameterChoice with the specified parameters.

        @param parameterID         The parameter ID to use
        @param parameterName       The parameter name to use
        @param choices             The set of choices to use
        @param defaultItemIndex    The index of the default choice
        @param parameterLabel      An optional label for the parameter's value
        @param stringFromIndex     An optional lambda function that converts a choice
                                   index to a string with a maximum length. This may
                                   be used by hosts to display the parameter's value.
        @param indexFromString     An optional lambda function that parses a string and
                                   converts it into a choice index. Some hosts use this
                                   to allow users to type in parameter values.
    */
    AudioParameterChoice (const String& parameterID, const String& parameterName,
                          const StringArray& choices,
                          int defaultItemIndex,
                          const String& parameterLabel = String(),
                          std::function<String(int index, int maximumStringLength)> stringFromIndex = nullptr,
                          std::function<int(const String& text)> indexFromString = nullptr);

    /** Destructor. */
    ~AudioParameterChoice() override;

    /** Returns the current index of the selected item. */
    int getIndex() const noexcept                   { return roundToInt (value.load()); }

    /** Returns the current index of the selected item. */
    operator int() const noexcept                   { return getIndex(); }

    /** Returns the name of the currently selected item. */
    String getCurrentChoiceName() const noexcept    { return choices[getIndex()]; }

    /** Returns the name of the currently selected item. */
    operator String() const noexcept                { return getCurrentChoiceName(); }

    /** Changes the selected item to a new index. */
    AudioParameterChoice& operator= (int newValue);

    /** Returns the range of values that the parameter can take. */
    const NormalisableRange<float>& getNormalisableRange() const override   { return range; }

    /** Provides access to the list of choices that this parameter is working with. */
    const StringArray choices;

protected:
    /** Override this method if you are interested in receiving callbacks
        when the parameter value changes.
    */
    virtual void valueChanged (int newValue);

private:
    //==============================================================================
    float getValue() const override;
    void setValue (float newValue) override;
    float getDefaultValue() const override;
    int getNumSteps() const override;
    bool isDiscrete() const override;
    String getText (float, int) const override;
    float getValueForText (const String&) const override;

    const NormalisableRange<float> range;
    std::atomic<float> value;
    const float defaultValue;
    std::function<String(int, int)> stringFromIndexFunction;
    std::function<int(const String&)> indexFromStringFunction;

    JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (AudioParameterChoice)
};

} // namespace juce