From d2189aa0f4bf2ca7e2ad7aca81da2e86eaaaee7d Mon Sep 17 00:00:00 2001
From: Andrzej Rybczak <electricityispower@gmail.com>
Date: Tue, 1 Sep 2015 21:43:58 +0200
Subject: [PATCH] visualizer: scale automatically if multiplier is 1

---
 NEWS               |  1 +
 src/status.cpp     |  3 +++
 src/visualizer.cpp | 24 ++++++++++++++++++++++--
 src/visualizer.h   |  2 ++
 4 files changed, 28 insertions(+), 2 deletions(-)

diff --git a/NEWS b/NEWS
index 931471d2..91ddd1eb 100644
--- a/NEWS
+++ b/NEWS
@@ -29,6 +29,7 @@ ncmpcpp-0.7 (????-??-??)
 * Support for selecting found items was added (bound to Ctrl-_ by default).
 * Tracks in media library are now properly sorted for track numbers greater than 99.
 * Value of 'visualizer_sync_interval' is now restricted to be greater than 9.
+* Output of the visualizer now scales automatically as long as 'visualizer_sample_multiplier' is set to 1.
 
 ncmpcpp-0.6.5 (2015-07-05)
 
diff --git a/src/status.cpp b/src/status.cpp
index 12c09ad1..7c9f5352 100644
--- a/src/status.cpp
+++ b/src/status.cpp
@@ -526,6 +526,9 @@ void Status::Changes::songID(int song_id)
 	playing_song_scroll_begin = 0;
 	first_line_scroll_begin = 0;
 	second_line_scroll_begin = 0;
+#	ifdef ENABLE_VISUALIZER
+	myVisualizer->ResetAutoScaleMultiplier();
+#	endif // ENABLE_VISUALIZER
 	if (m_player_state != MPD::psStop)
 	{
 		auto &pl = myPlaylist->main();
diff --git a/src/visualizer.cpp b/src/visualizer.cpp
index 2ba53ad7..6d10d367 100644
--- a/src/visualizer.cpp
+++ b/src/visualizer.cpp
@@ -148,8 +148,23 @@ void Visualizer::update()
 	}
 
 	const ssize_t samples_read = data/sizeof(int16_t);
-	std::for_each(buf, buf+samples_read, [](int16_t &sample) {
-		int32_t tmp = sample * Config.visualizer_sample_multiplier;
+	if (Config.visualizer_sample_multiplier == 1.0)
+	{
+		m_auto_scale_multiplier += 1.0/fps;
+		std::for_each(buf, buf+samples_read, [this](int16_t &sample) {
+			double scale = std::numeric_limits<int16_t>::min();
+			scale /= sample;
+			scale = fabs(scale);
+			if (scale < m_auto_scale_multiplier)
+				m_auto_scale_multiplier = scale;
+		});
+	}
+	std::for_each(buf, buf+samples_read, [this](int16_t &sample) {
+		int32_t tmp = sample;
+		if (Config.visualizer_sample_multiplier != 1.0)
+			tmp *= Config.visualizer_sample_multiplier;
+		else if (m_auto_scale_multiplier <= 50.0) // limit the auto scale
+			tmp *= m_auto_scale_multiplier;
 		if (tmp < std::numeric_limits<int16_t>::min())
 			sample = std::numeric_limits<int16_t>::min();
 		else if (tmp > std::numeric_limits<int16_t>::max())
@@ -474,6 +489,11 @@ void Visualizer::FindOutputID()
 	}
 }
 
+void Visualizer::ResetAutoScaleMultiplier()
+{
+	m_auto_scale_multiplier = std::numeric_limits<double>::infinity();
+}
+
 #endif // ENABLE_VISUALIZER
 
 /* vim: set tabstop=4 softtabstop=4 shiftwidth=4 noexpandtab : */
diff --git a/src/visualizer.h b/src/visualizer.h
index 48fd4d5f..8baf608a 100644
--- a/src/visualizer.h
+++ b/src/visualizer.h
@@ -60,6 +60,7 @@ struct Visualizer: Screen<NC::Window>, Tabbable
 	void SetFD();
 	void ResetFD();
 	void FindOutputID();
+	void ResetAutoScaleMultiplier();
 
 private:
 	void DrawSoundWave(int16_t *, ssize_t, size_t, size_t);
@@ -78,6 +79,7 @@ private:
 
 	int m_fifo;
 	size_t m_samples;
+	double m_auto_scale_multiplier;
 #	ifdef HAVE_FFTW3_H
 	size_t m_fftw_results;
 	double *m_fftw_input;