Add visualizer_spectrum_gain option to a configuration file

src/screens/visualizer.cpp

@@ -75,10 +75,10 @@ Visualizer::Visualizer()
 	,
   DFT_NONZERO_SIZE(1 << Config.visualizer_spectrum_dft_size),
   DFT_TOTAL_SIZE(Config.visualizer_spectrum_dft_size >= MIN_DFT_SIZE ? 1 << (Config.visualizer_spectrum_dft_size) : 1<<MIN_DFT_SIZE),
-  DYNAMIC_RANGE(100),
+  DYNAMIC_RANGE(100-Config.visualizer_spectrum_gain),
   HZ_MIN(Config.visualizer_spectrum_hz_min),
   HZ_MAX(Config.visualizer_spectrum_hz_max),
-  GAIN(0),
+  GAIN(Config.visualizer_spectrum_gain),
   SMOOTH_CHARS(ToWString("▁▂▃▄▅▆▇█"))
 #endif
 {

src/settings.cpp

@@ -301,6 +301,12 @@ bool Configuration::read(const std::vector<std::string> &config_paths, bool igno
       boundsCheck<uint32_t>(result, 0, 4);
 			return result + 14;
 			});
+	p.add("visualizer_spectrum_gain", &visualizer_spectrum_gain,
+			"20", [](std::string v) {
+			auto result = verbose_lexical_cast<double>(v);
+			boundsCheck<double>(result, 0, 100);
+			return result;
+			});
 	p.add("visualizer_spectrum_hz_min", &visualizer_spectrum_hz_min,
 			"20", [](std::string v) {
 			auto result = verbose_lexical_cast<double>(v);

src/settings.h

@@ -85,6 +85,7 @@ struct Configuration
 	bool visualizer_autoscale;
 	bool visualizer_spectrum_smooth_look;
 	uint32_t visualizer_spectrum_dft_size;
+	double visualizer_spectrum_gain;
 	double visualizer_spectrum_hz_min;
 	double visualizer_spectrum_hz_max;