Add option to specifiy rate of change instead of duration for audio fade

src/headers/macro-action-audio.hpp

@@ -3,6 +3,7 @@
 #include "duration-control.hpp"
 
 #include <QSpinBox>
+#include <QDoubleSpinBox>
 #include <QCheckBox>
 #include <QHBoxLayout>
 
@@ -13,6 +14,11 @@ enum class AudioAction {
 	MASTER_VOLUME,
 };
 
+enum class FadeType {
+	DURATION,
+	RATE,
+};
+
 class MacroActionAudio : public MacroAction {
 public:
 	MacroActionAudio(Macro *m) : MacroAction(m) {}
@@ -29,9 +35,11 @@ public:
 
 	OBSWeakSource _audioSource;
 	AudioAction _action = AudioAction::MUTE;
+	FadeType _fadeType = FadeType::DURATION;
 	int _volume = 0;
 	bool _fade = false;
 	Duration _duration;
+	double _rate = 100.;
 	bool _wait = false;
 
 private:
@@ -67,16 +75,20 @@ private slots:
 	void VolumeChanged(int value);
 	void FadeChanged(int value);
 	void DurationChanged(double seconds);
+	void RateChanged(double value);
 	void WaitChanged(int value);
+	void FadeTypeChanged(int value);
 signals:
 	void HeaderInfoChanged(const QString &);
 
 protected:
 	QComboBox *_audioSources;
 	QComboBox *_actions;
+	QComboBox *_fadeTypes;
 	QSpinBox *_volumePercent;
 	QCheckBox *_fade;
 	DurationSelection *_duration;
+	QDoubleSpinBox *_rate;
 	QCheckBox *_wait;
 	QHBoxLayout *_fadeLayout;
 	std::shared_ptr<MacroActionAudio> _entryData;