New Spectrum Analyzer (#4950)

Replace old spectrum analyzer by new one with higher resolution and
many new features.

Resolves #2847.

include/EffectControlDialog.h

@@ -40,6 +40,8 @@ public:
 	EffectControlDialog( EffectControls * _controls );
 	virtual ~EffectControlDialog();
 
+	virtual bool isResizable() const {return false;}
+
 
 signals:
 	void closed();

include/SubWindow.h

@@ -30,7 +30,6 @@
 #include <QGraphicsDropShadowEffect>
 #include <QMdiSubWindow>
 #include <QLabel>
-#include <QPainter>
 #include <QPushButton>
 #include <QString>
 

include/fft_helpers.h

@@ -2,6 +2,7 @@
  * fft_helpers.h - some functions around FFT analysis
  *
  * Copyright (c) 2008-2012 Tobias Doerffel <tobydox/at/users.sourceforge.net>
+ * Copyright (c) 2019 Martin Pavelek <he29.HS/at/gmail.com>
  *
  * This file is part of LMMS - https://lmms.io
  *
@@ -28,57 +29,90 @@
 
 #include "lmms_export.h"
 
+#include <vector>
 #include <fftw3.h>
 
-const int FFT_BUFFER_SIZE = 2048;
+// NOTE: FFT_BUFFER_SIZE should be considered deprecated!
+// It is used by Eq plugin and some older code here, but this should be a user
+// switchable parameter, not a constant. Use a value from FFT_BLOCK_SIZES
+const unsigned int FFT_BUFFER_SIZE = 2048;
 
-enum WINDOWS
+// Allowed FFT block sizes. Ranging from barely useful to barely acceptable
+// because of performance and latency reasons.
+const std::vector<unsigned int> FFT_BLOCK_SIZES = {256, 512, 1024, 2048, 4096, 8192, 16384};
+
+// List of FFT window functions supported by precomputeWindow()
+enum FFT_WINDOWS
 {
-        KAISER=1,
-        RECTANGLE,
-        HANNING,
-        HAMMING
+	RECTANGULAR = 0,
+	BLACKMAN_HARRIS,
+	HAMMING,
+	HANNING
 };
 
-/* returns biggest value from abs_spectrum[spec_size] array
+
+/**	Returns biggest value from abs_spectrum[spec_size] array.
  *
- *    returns -1 on error
+ *	@return -1 on error, 0 on success
  */
-float LMMS_EXPORT maximum( float * _abs_spectrum, unsigned int _spec_size );
+float LMMS_EXPORT maximum(const float *abs_spectrum, unsigned int spec_size);
+float LMMS_EXPORT maximum(const std::vector<float> &abs_spectrum);
 
-/* apply hanning or hamming window to channel
+
+/** Normalize the abs_spectrum array of absolute values to a 0..1 range
+ *	based on supplied energy and stores it in the norm_spectrum array.
  *
- *    returns -1 on error
+ *	@return -1 on error
  */
-int LMMS_EXPORT hanming( float * _timebuffer, int _length, WINDOWS _type );
+int LMMS_EXPORT normalize(const float *abs_spectrum, float *norm_spectrum, unsigned int bin_count, unsigned int block_size);
+int LMMS_EXPORT normalize(const std::vector<float> &abs_spectrum, std::vector<float> &norm_spectrum, unsigned int block_size);
 
-/* compute absolute values of complex_buffer, save to absspec_buffer
- * take care that - compl_len is not bigger than complex_buffer!
- *                - absspec buffer is big enough!
+
+/**	Check if the spectrum contains any non-zero value.
  *
- *    returns 0 on success, else -1
+ *	@return 1 if spectrum contains any non-zero value
+ *	@return 0 otherwise
  */
-int LMMS_EXPORT absspec( fftwf_complex * _complex_buffer, float * _absspec_buffer,
-							int _compl_length );
+int LMMS_EXPORT notEmpty(const std::vector<float> &spectrum);
 
-/* build fewer subbands from many absolute spectrum values
- * take care that - compressedbands[] array num_new elements long
- *                - num_old > num_new
+
+/**	Precompute a window function for later real-time use.
+ *	Set normalized to false if you do not want to apply amplitude correction.
  *
- *    returns 0 on success, else -1
+ *	@return -1 on error
  */
-int LMMS_EXPORT compressbands( float * _absspec_buffer, float * _compressedband,
-			int _num_old, int _num_new, int _bottom, int _top );
+int LMMS_EXPORT precomputeWindow(float *window, unsigned int length, FFT_WINDOWS type, bool normalized = true);
 
 
-int LMMS_EXPORT calc13octaveband31( float * _absspec_buffer, float * _subbands,
-				int _num_spec, float _max_frequency );
-
-/* compute power of finite time sequence
- * take care num_values is length of timesignal[]
+/**	Compute absolute values of complex_buffer, save to absspec_buffer.
+ *	Take care that - compl_len is not bigger than complex_buffer!
+ *				   - absspec buffer is big enough!
  *
- *    returns power on success, else -1
+ *	@return 0 on success, else -1
  */
-float LMMS_EXPORT signalpower(float *timesignal, int num_values);
+int LMMS_EXPORT absspec(const fftwf_complex *complex_buffer, float *absspec_buffer,
+						unsigned int compl_length);
+
+
+/**	Build fewer subbands from many absolute spectrum values.
+ *	Take care that - compressedbands[] array num_new elements long
+ *				   - num_old > num_new
+ *
+ *	@return 0 on success, else -1
+ */
+int LMMS_EXPORT compressbands(const float * _absspec_buffer, float * _compressedband,
+			int _num_old, int _num_new, int _bottom, int _top);
+
+
+int LMMS_EXPORT calc13octaveband31(float * _absspec_buffer, float * _subbands,
+				int _num_spec, float _max_frequency);
+
+
+/**	Compute power of finite time sequence.
+ *	Take care num_values is length of timesignal[].
+ *
+ *	@return power on success, else -1
+ */
+float LMMS_EXPORT signalpower(const float *timesignal, int num_values);
 
 #endif

plugins/SpectrumAnalyzer/Analyzer.cpp

@@ -0,0 +1,75 @@
+/*
+ * Analyzer.cpp - definition of Analyzer class.
+ *
+ * Copyright (c) 2019 Martin Pavelek <he29/dot/HS/at/gmail/dot/com>
+ *
+ * Based partially on Eq plugin code,
+ * Copyright (c) 2014-2017, David French <dave/dot/french3/at/googlemail/dot/com>
+ *
+ * This file is part of LMMS - https://lmms.io
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program (see COPYING); if not, write to the
+ * Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+ * Boston, MA 02110-1301 USA.
+ *
+ */
+
+#include "Analyzer.h"
+
+#include "embed.h"
+#include "plugin_export.h"
+
+
+extern "C" {
+	Plugin::Descriptor PLUGIN_EXPORT analyzer_plugin_descriptor =
+	{
+		"spectrumanalyzer",
+		"Spectrum Analyzer",
+		QT_TRANSLATE_NOOP("pluginBrowser", "A graphical spectrum analyzer."),
+		"Martin Pavelek <he29/dot/HS/at/gmail/dot/com>",
+		0x0100,
+		Plugin::Effect,
+		new PluginPixmapLoader("logo"),
+		NULL,
+		NULL
+	};
+}
+
+
+Analyzer::Analyzer(Model *parent, const Plugin::Descriptor::SubPluginFeatures::Key *key) :
+	Effect(&analyzer_plugin_descriptor, parent, key),
+	m_processor(&m_controls),
+	m_controls(this)
+{
+}
+
+
+// Take audio data and pass them to the spectrum processor.
+// Skip processing if the controls dialog isn't visible, it would only waste CPU cycles.
+bool Analyzer::processAudioBuffer(sampleFrame *buffer, const fpp_t frame_count)
+{
+	if (!isEnabled() || !isRunning ()) {return false;}
+	if (m_controls.isViewVisible()) {m_processor.analyse(buffer, frame_count);}
+	return isRunning();
+}
+
+
+extern "C" {
+	// needed for getting plugin out of shared lib
+	PLUGIN_EXPORT Plugin *lmms_plugin_main(Model *parent, void *data)
+	{
+		return new Analyzer(parent, static_cast<const Plugin::Descriptor::SubPluginFeatures::Key *>(data));
+	}
+}
+

plugins/SpectrumAnalyzer/Analyzer.h

@@ -1,7 +1,9 @@
-/*
- * SpectrumAnalyzerControlDialog.h - view for spectrum analyzer
+/* Analyzer.h - declaration of Analyzer class.
  *
- * Copyright (c) 2008-2014 Tobias Doerffel <tobydox/at/users.sourceforge.net>
+ * Copyright (c) 2019 Martin Pavelek <he29/dot/HS/at/gmail/dot/com>
+ *
+ * Based partially on Eq plugin code,
+ * Copyright (c) 2014-2017, David French <dave/dot/french3/at/googlemail/dot/com>
  *
  * This file is part of LMMS - https://lmms.io
  *
@@ -22,32 +24,30 @@
  *
  */
 
-#ifndef _SPECTRUM_ANALYZER_CONTROL_DIALOG_H
-#define _SPECTRUM_ANALYZER_CONTROL_DIALOG_H
+#ifndef ANALYZER_H
+#define ANALYZER_H
 
-#include "EffectControlDialog.h"
+#include "Effect.h"
+#include "SaControls.h"
+#include "SaProcessor.h"
 
 
-class SpectrumAnalyzerControls;
-
-
-class SpectrumAnalyzerControlDialog : public EffectControlDialog
+//! Top level class; handles LMMS interface and feeds data to the data processor.
+class Analyzer : public Effect
 {
-	Q_OBJECT
 public:
-	SpectrumAnalyzerControlDialog( SpectrumAnalyzerControls* controls );
-	virtual ~SpectrumAnalyzerControlDialog()
-	{
-	}
+	Analyzer(Model *parent, const Descriptor::SubPluginFeatures::Key *key);
+	virtual ~Analyzer() {};
+
+	bool processAudioBuffer(sampleFrame *buffer, const fpp_t frame_count) override;
+	EffectControls *controls() override {return &m_controls;}
+
+	SaProcessor *getProcessor() {return &m_processor;}
 
 private:
-	virtual void paintEvent( QPaintEvent* event );
+	SaProcessor m_processor;
+	SaControls m_controls;
+};
 
-	SpectrumAnalyzerControls* m_controls;
+#endif // ANALYZER_H
 
-	QPixmap m_logXAxis;
-	QPixmap m_logYAxis;
-
-} ;
-
-#endif

plugins/SpectrumAnalyzer/CMakeLists.txt

@@ -1,4 +1,5 @@
 INCLUDE(BuildPlugin)
 INCLUDE_DIRECTORIES(${FFTW3F_INCLUDE_DIRS})
 LINK_LIBRARIES(${FFTW3F_LIBRARIES})
-BUILD_PLUGIN(spectrumanalyzer SpectrumAnalyzer.cpp SpectrumAnalyzerControls.cpp SpectrumAnalyzerControlDialog.cpp SpectrumAnalyzer.h SpectrumAnalyzerControls.h SpectrumAnalyzerControlDialog.h MOCFILES SpectrumAnalyzerControlDialog.h SpectrumAnalyzerControls.h EMBEDDED_RESOURCES *.png)
+BUILD_PLUGIN(analyzer Analyzer.cpp SaProcessor.cpp SaControls.cpp SaControlsDialog.cpp SaSpectrumView.cpp SaWaterfallView.cpp
+MOCFILES SaProcessor.h SaControls.h SaControlsDialog.h SaSpectrumView.h SaWaterfallView.h EMBEDDED_RESOURCES *.svg logo.png)

plugins/SpectrumAnalyzer/README.md

@@ -0,0 +1,19 @@
+# Spectrum Analyzer plugin
+
+## Overview
+
+This plugin consists of three widgets and back-end code to provide them with required data.
+
+The top-level widget is SaControlDialog. It populates a configuration widget (created dynamically) and instantiates spectrum display widgets. Its main back-end class is SaControls, which holds all configuration values and globally valid constants (e.g. range definitions).
+
+SaSpectrumDisplay and SaWaterfallDisplay show the result of spectrum analysis. Their main back-end class is SaProcessor, which performs FFT analysis on data received from the Analyzer class, which in turn handles the interface with LMMS.
+
+
+## Changelog
+
+	1.0.1	2019-06-02
+		- code style changes
+		- added tool-tips
+		- use const for unmodified arrays passed to fft_helpers
+	1.0.0	2019-04-07
+		- initial release

plugins/SpectrumAnalyzer/SaControls.cpp

@@ -0,0 +1,144 @@
+/*
+ * SaControls.cpp - definition of SaControls class.
+ *
+ * Copyright (c) 2019 Martin Pavelek <he29/dot/HS/at/gmail/dot/com>
+ *
+ * This file is part of LMMS - https://lmms.io
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program (see COPYING); if not, write to the
+ * Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+ * Boston, MA 02110-1301 USA.
+ *
+ */
+
+#include "SaControls.h"
+
+#include <QtXml/QDomElement>
+
+#include "Analyzer.h"
+#include "SaControlsDialog.h"
+
+
+SaControls::SaControls(Analyzer *effect) :
+	EffectControls(effect),
+	m_effect(effect),
+
+	// initialize bool models and set default values
+	m_pauseModel(false, this, tr("Pause")),
+	m_refFreezeModel(false, this, tr("Reference freeze")),
+
+	m_waterfallModel(false, this, tr("Waterfall")),
+	m_smoothModel(false, this, tr("Averaging")),
+	m_stereoModel(false, this, tr("Stereo")),
+	m_peakHoldModel(false, this, tr("Peak hold")),
+
+	m_logXModel(true, this, tr("Logarithmic frequency")),
+	m_logYModel(true, this, tr("Logarithmic amplitude")),
+
+	// default values of combo boxes are set after they are populated
+	m_freqRangeModel(this, tr("Frequency range")),
+	m_ampRangeModel(this, tr("Amplitude range")),
+	m_blockSizeModel(this, tr("FFT block size")),
+	m_windowModel(this, tr("FFT window type"))
+{
+	// Frequency and amplitude ranges; order must match
+	// FREQUENCY_RANGES and AMPLITUDE_RANGES defined in SaControls.h
+	m_freqRangeModel.addItem(tr("Full (auto)"));
+	m_freqRangeModel.addItem(tr("Audible"));
+	m_freqRangeModel.addItem(tr("Bass"));
+	m_freqRangeModel.addItem(tr("Mids"));
+	m_freqRangeModel.addItem(tr("High"));
+	m_freqRangeModel.setValue(m_freqRangeModel.findText(tr("Full (auto)")));
+
+	m_ampRangeModel.addItem(tr("Extended"));
+	m_ampRangeModel.addItem(tr("Default"));
+	m_ampRangeModel.addItem(tr("Audible"));
+	m_ampRangeModel.addItem(tr("Noise"));
+	m_ampRangeModel.setValue(m_ampRangeModel.findText(tr("Default")));
+
+	// FFT block size labels are generated automatically, based on
+	// FFT_BLOCK_SIZES vector defined in fft_helpers.h
+	for (unsigned int i = 0; i < FFT_BLOCK_SIZES.size(); i++)
+	{
+		if (i == 0)
+		{
+			m_blockSizeModel.addItem((std::to_string(FFT_BLOCK_SIZES[i]) + " ").c_str() + tr("(High time res.)"));
+		}
+		else if (i == FFT_BLOCK_SIZES.size() - 1)
+		{
+			m_blockSizeModel.addItem((std::to_string(FFT_BLOCK_SIZES[i]) + " ").c_str() + tr("(High freq. res.)"));
+		}
+		else
+		{
+			m_blockSizeModel.addItem(std::to_string(FFT_BLOCK_SIZES[i]).c_str());
+		}
+	}
+	m_blockSizeModel.setValue(m_blockSizeModel.findText("2048"));
+
+	// Window type order must match FFT_WINDOWS defined in fft_helpers.h
+	m_windowModel.addItem(tr("Rectangular (Off)"));
+	m_windowModel.addItem(tr("Blackman-Harris (Default)"));
+	m_windowModel.addItem(tr("Hamming"));
+	m_windowModel.addItem(tr("Hanning"));
+	m_windowModel.setValue(m_windowModel.findText(tr("Blackman-Harris (Default)")));
+
+	// Colors
+	// Background color is defined by Qt / theme.
+	// Make sure the sum of colors for L and R channel stays lower or equal
+	// to 255. Otherwise the Waterfall pixels may overflow back to 0 even when
+	// the input signal isn't clipping (over 1.0).
+	m_colorL = QColor(51, 148, 204, 135);
+	m_colorR = QColor(204, 107, 51, 135);
+	m_colorMono = QColor(51, 148, 204, 204);
+	m_colorBG = QColor(7, 7, 7, 255);			// ~20 % gray (after gamma correction)
+	m_colorGrid = QColor(30, 34, 38, 255);		// ~40 % gray (slightly cold / blue)
+	m_colorLabels = QColor(192, 202, 212, 255);	// ~90 % gray (slightly cold / blue)
+}
+
+
+// Create the SaControlDialog widget which handles display of GUI elements.
+EffectControlDialog* SaControls::createView()
+{
+	return new SaControlsDialog(this, m_effect->getProcessor());
+}
+
+
+void SaControls::loadSettings(const QDomElement &_this)
+{
+	m_waterfallModel.loadSettings(_this, "Waterfall");
+	m_smoothModel.loadSettings(_this, "Smooth");
+	m_stereoModel.loadSettings(_this, "Stereo");
+	m_peakHoldModel.loadSettings(_this, "PeakHold");
+	m_logXModel.loadSettings(_this, "LogX");
+	m_logYModel.loadSettings(_this, "LogY");
+	m_freqRangeModel.loadSettings(_this, "RangeX");
+	m_ampRangeModel.loadSettings(_this, "RangeY");
+	m_blockSizeModel.loadSettings(_this, "BlockSize");
+	m_windowModel.loadSettings(_this, "WindowType");
+}
+
+
+void SaControls::saveSettings(QDomDocument &doc, QDomElement &parent)
+{
+	m_waterfallModel.saveSettings(doc, parent, "Waterfall");
+	m_smoothModel.saveSettings(doc, parent, "Smooth");
+	m_stereoModel.saveSettings(doc, parent, "Stereo");
+	m_peakHoldModel.saveSettings(doc, parent, "PeakHold");
+	m_logXModel.saveSettings(doc, parent, "LogX");
+	m_logYModel.saveSettings(doc, parent, "LogY");
+	m_freqRangeModel.saveSettings(doc, parent, "RangeX");
+	m_ampRangeModel.saveSettings(doc, parent, "RangeY");
+	m_blockSizeModel.saveSettings(doc, parent, "BlockSize");
+	m_windowModel.saveSettings(doc, parent, "WindowType");
+}

plugins/SpectrumAnalyzer/SaControls.h

@@ -0,0 +1,126 @@
+/*
+ * SaControls.h - declaration of SaControls class.
+ *
+ * Copyright (c) 2019 Martin Pavelek <he29/dot/HS/at/gmail/dot/com>
+ *
+ * This file is part of LMMS - https://lmms.io
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program (see COPYING); if not, write to the
+ * Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+ * Boston, MA 02110-1301 USA.
+ *
+ */
+
+#ifndef SACONTROLS_H
+#define SACONTROLS_H
+
+#include "ComboBoxModel.h"
+#include "EffectControls.h"
+
+//#define SA_DEBUG 1	// define SA_DEBUG to enable performance measurements
+
+// Frequency ranges (in Hz).
+// Full range is defined by LOWEST_LOG_FREQ and current sample rate.
+const int LOWEST_LOG_FREQ = 10;		// arbitrary low limit for log. scale, >1
+
+enum FREQUENCY_RANGES
+{
+	FRANGE_FULL = 0,
+	FRANGE_AUDIBLE,
+	FRANGE_BASS,
+	FRANGE_MIDS,
+	FRANGE_HIGH
+};
+
+const int FRANGE_AUDIBLE_START = 20;
+const int FRANGE_AUDIBLE_END = 20000;
+const int FRANGE_BASS_START = 20;
+const int FRANGE_BASS_END = 300;
+const int FRANGE_MIDS_START = 200;
+const int FRANGE_MIDS_END = 5000;
+const int FRANGE_HIGH_START = 4000;
+const int FRANGE_HIGH_END = 20000;
+
+// Amplitude ranges.
+// Reference: sine wave from -1.0 to 1.0 = 0 dB.
+// I.e. if master volume is 100 %, positive values signify clipping.
+// Doubling or halving the amplitude produces 3 dB difference.
+enum AMPLITUDE_RANGES
+{
+	ARANGE_EXTENDED = 0,
+	ARANGE_DEFAULT,
+	ARANGE_AUDIBLE,
+	ARANGE_NOISE
+};
+
+const int ARANGE_EXTENDED_START = -80;
+const int ARANGE_EXTENDED_END = 20;
+const int ARANGE_DEFAULT_START = -30;
+const int ARANGE_DEFAULT_END = 0;
+const int ARANGE_AUDIBLE_START = -50;
+const int ARANGE_AUDIBLE_END = 10;
+const int ARANGE_NOISE_START = -60;
+const int ARANGE_NOISE_END = -20;
+
+
+class Analyzer;
+
+// Holds all the configuration values
+class SaControls : public EffectControls
+{
+	Q_OBJECT
+public:
+	explicit SaControls(Analyzer* effect);
+	virtual ~SaControls() {}
+
+	EffectControlDialog* createView() override;
+
+	void saveSettings (QDomDocument& doc, QDomElement& parent) override;
+	void loadSettings (const QDomElement &_this) override;
+
+	QString nodeName() const override {return "Analyzer";}
+	int controlCount() override {return 12;}
+
+private:
+	Analyzer *m_effect;
+
+	BoolModel m_pauseModel;
+	BoolModel m_refFreezeModel;
+
+	BoolModel m_waterfallModel;
+	BoolModel m_smoothModel;
+	BoolModel m_stereoModel;
+	BoolModel m_peakHoldModel;
+
+	BoolModel m_logXModel;
+	BoolModel m_logYModel;
+
+	ComboBoxModel m_freqRangeModel;
+	ComboBoxModel m_ampRangeModel;
+	ComboBoxModel m_blockSizeModel;
+	ComboBoxModel m_windowModel;
+
+	QColor	m_colorL;
+	QColor	m_colorR;
+	QColor	m_colorMono;
+	QColor	m_colorBG;
+	QColor	m_colorGrid;
+	QColor	m_colorLabels;
+
+	friend class SaControlsDialog;
+	friend class SaSpectrumView;
+	friend class SaWaterfallView;
+	friend class SaProcessor;
+};
+#endif // SACONTROLS_H

plugins/SpectrumAnalyzer/SaControlsDialog.cpp

@@ -0,0 +1,227 @@
+/*
+ * SaControlsDialog.cpp - definition of SaControlsDialog class.
+ *
+ * Copyright (c) 2019 Martin Pavelek <he29/dot/HS/at/gmail/dot/com>
+ *
+ * This file is part of LMMS - https://lmms.io
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program (see COPYING); if not, write to the
+ * Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+ * Boston, MA 02110-1301 USA.
+ *
+ */
+
+#include "SaControlsDialog.h"
+
+#include <QGridLayout>
+#include <QLabel>
+#include <QSizePolicy>
+#include <QSplitter>
+#include <QWidget>
+
+#include "ComboBox.h"
+#include "ComboBoxModel.h"
+#include "embed.h"
+#include "Engine.h"
+#include "LedCheckbox.h"
+#include "PixmapButton.h"
+#include "SaControls.h"
+#include "SaProcessor.h"
+
+
+// The entire GUI layout is built here.
+SaControlsDialog::SaControlsDialog(SaControls *controls, SaProcessor *processor) :
+	EffectControlDialog(controls),
+	m_controls(controls),
+	m_processor(processor)
+{
+	// Top level placement of sections is handled by QSplitter widget.
+	QHBoxLayout *master_layout = new QHBoxLayout;
+	QSplitter *display_splitter = new QSplitter(Qt::Vertical);
+	master_layout->addWidget(display_splitter);
+	master_layout->setContentsMargins(2, 6, 2, 8);
+	setLayout(master_layout);
+
+	// QSplitter top: configuration section
+	QWidget *config_widget = new QWidget;
+	QGridLayout *config_layout = new QGridLayout;
+	config_widget->setSizePolicy(QSizePolicy::Minimum, QSizePolicy::Minimum);
+	config_widget->setMaximumHeight(m_configHeight);
+	config_widget->setLayout(config_layout);
+	display_splitter->addWidget(config_widget);
+
+	// Pre-compute target pixmap size based on monitor DPI.
+	// Using setDevicePixelRatio() on pixmap allows the SVG image to be razor
+	// sharp on High-DPI screens, but the desired size must be manually
+	// enlarged. No idea how to make Qt do it in a more reasonable way.
+	QSize iconSize = QSize(22.0 * devicePixelRatio(), 22.0 * devicePixelRatio());
+	QSize buttonSize = 1.2 * iconSize;
+
+	// pause and freeze buttons
+	PixmapButton *pauseButton = new PixmapButton(this, tr("Pause"));
+	pauseButton->setToolTip(tr("Pause data acquisition"));
+	QPixmap *pauseOnPixmap = new QPixmap(PLUGIN_NAME::getIconPixmap("play").scaled(buttonSize, Qt::IgnoreAspectRatio, Qt::SmoothTransformation));
+	QPixmap *pauseOffPixmap = new QPixmap(PLUGIN_NAME::getIconPixmap("pause").scaled(buttonSize, Qt::IgnoreAspectRatio, Qt::SmoothTransformation));
+	pauseOnPixmap->setDevicePixelRatio(devicePixelRatio());
+	pauseOffPixmap->setDevicePixelRatio(devicePixelRatio());
+	pauseButton->setActiveGraphic(*pauseOnPixmap);
+	pauseButton->setInactiveGraphic(*pauseOffPixmap);
+	pauseButton->setCheckable(true);
+	pauseButton->setModel(&controls->m_pauseModel);
+	config_layout->addWidget(pauseButton, 0, 0, 2, 1);
+
+	PixmapButton *refFreezeButton = new PixmapButton(this, tr("Reference freeze"));
+	refFreezeButton->setToolTip(tr("Freeze current input as a reference / disable falloff in peak-hold mode."));
+	QPixmap *freezeOnPixmap = new QPixmap(PLUGIN_NAME::getIconPixmap("freeze").scaled(buttonSize, Qt::IgnoreAspectRatio, Qt::SmoothTransformation));
+	QPixmap *freezeOffPixmap = new QPixmap(PLUGIN_NAME::getIconPixmap("freeze_off").scaled(buttonSize, Qt::IgnoreAspectRatio, Qt::SmoothTransformation));
+	freezeOnPixmap->setDevicePixelRatio(devicePixelRatio());
+	freezeOffPixmap->setDevicePixelRatio(devicePixelRatio());
+	refFreezeButton->setActiveGraphic(*freezeOnPixmap);
+	refFreezeButton->setInactiveGraphic(*freezeOffPixmap);
+	refFreezeButton->setCheckable(true);
+	refFreezeButton->setModel(&controls->m_refFreezeModel);
+	config_layout->addWidget(refFreezeButton, 2, 0, 2, 1);
+
+	// misc configuration switches
+	LedCheckBox *waterfallButton = new LedCheckBox(tr("Waterfall"), this);
+	waterfallButton->setToolTip(tr("Display real-time spectrogram"));
+	waterfallButton->setCheckable(true);
+	waterfallButton->setMinimumSize(70, 12);
+	waterfallButton->setModel(&controls->m_waterfallModel);
+	config_layout->addWidget(waterfallButton, 0, 1);
+
+	LedCheckBox *smoothButton = new LedCheckBox(tr("Averaging"), this);
+	smoothButton->setToolTip(tr("Enable exponential moving average"));
+	smoothButton->setCheckable(true);
+	smoothButton->setMinimumSize(70, 12);
+	smoothButton->setModel(&controls->m_smoothModel);
+	config_layout->addWidget(smoothButton, 1, 1);
+
+	LedCheckBox *stereoButton = new LedCheckBox(tr("Stereo"), this);
+	stereoButton->setToolTip(tr("Display stereo channels separately"));
+	stereoButton->setCheckable(true);
+	stereoButton->setMinimumSize(70, 12);
+	stereoButton->setModel(&controls->m_stereoModel);
+	config_layout->addWidget(stereoButton, 2, 1);
+
+	LedCheckBox *peakHoldButton = new LedCheckBox(tr("Peak hold"), this);
+	peakHoldButton->setToolTip(tr("Display envelope of peak values"));
+	peakHoldButton->setCheckable(true);
+	peakHoldButton->setMinimumSize(70, 12);
+	peakHoldButton->setModel(&controls->m_peakHoldModel);
+	config_layout->addWidget(peakHoldButton, 3, 1);
+
+	// frequency: linear / log. switch and range selector
+	PixmapButton *logXButton = new PixmapButton(this, tr("Logarithmic frequency"));
+	logXButton->setToolTip(tr("Switch between logarithmic and linear frequency scale"));
+	QPixmap *logXOnPixmap = new QPixmap(PLUGIN_NAME::getIconPixmap("x_log").scaled(iconSize, Qt::IgnoreAspectRatio, Qt::SmoothTransformation));
+	QPixmap *logXOffPixmap = new QPixmap(PLUGIN_NAME::getIconPixmap("x_linear").scaled(iconSize, Qt::IgnoreAspectRatio, Qt::SmoothTransformation));
+	logXOnPixmap->setDevicePixelRatio(devicePixelRatio());
+	logXOffPixmap->setDevicePixelRatio(devicePixelRatio());
+	logXButton->setActiveGraphic(*logXOnPixmap);
+	logXButton->setInactiveGraphic(*logXOffPixmap);
+	logXButton->setCheckable(true);
+	logXButton->setModel(&controls->m_logXModel);
+	config_layout->addWidget(logXButton, 0, 2, 2, 1, Qt::AlignRight);
+
+	ComboBox *freqRangeCombo = new ComboBox(this, tr("Frequency range"));
+	freqRangeCombo->setToolTip(tr("Frequency range"));
+	freqRangeCombo->setMinimumSize(100, 22);
+	freqRangeCombo->setMaximumSize(200, 22);
+	freqRangeCombo->setModel(&controls->m_freqRangeModel);
+	config_layout->addWidget(freqRangeCombo, 0, 3, 2, 1);
+
+	// amplitude: linear / log switch and range selector
+	PixmapButton *logYButton = new PixmapButton(this, tr("Logarithmic amplitude"));
+	logYButton->setToolTip(tr("Switch between logarithmic and linear amplitude scale"));
+	QPixmap *logYOnPixmap = new QPixmap(PLUGIN_NAME::getIconPixmap("y_log").scaled(iconSize, Qt::IgnoreAspectRatio, Qt::SmoothTransformation));
+	QPixmap *logYOffPixmap = new QPixmap(PLUGIN_NAME::getIconPixmap("y_linear").scaled(iconSize, Qt::IgnoreAspectRatio, Qt::SmoothTransformation));
+	logYOnPixmap->setDevicePixelRatio(devicePixelRatio());
+	logYOffPixmap->setDevicePixelRatio(devicePixelRatio());
+	logYButton->setActiveGraphic(*logYOnPixmap);
+	logYButton->setInactiveGraphic(*logYOffPixmap);
+	logYButton->setCheckable(true);
+	logYButton->setModel(&controls->m_logYModel);
+	config_layout->addWidget(logYButton, 2, 2, 2, 1, Qt::AlignRight);
+
+	ComboBox *ampRangeCombo = new ComboBox(this, tr("Amplitude range"));
+	ampRangeCombo->setToolTip(tr("Amplitude range"));
+	ampRangeCombo->setMinimumSize(100, 22);
+	ampRangeCombo->setMaximumSize(200, 22);
+	ampRangeCombo->setModel(&controls->m_ampRangeModel);
+	config_layout->addWidget(ampRangeCombo, 2, 3, 2, 1);
+
+	// FFT: block size: icon and selector
+	QLabel *blockSizeLabel = new QLabel("", this);
+	QPixmap *blockSizeIcon = new QPixmap(PLUGIN_NAME::getIconPixmap("block_size"));
+	blockSizeIcon->setDevicePixelRatio(devicePixelRatio());
+	blockSizeLabel->setPixmap(blockSizeIcon->scaled(iconSize, Qt::IgnoreAspectRatio, Qt::SmoothTransformation));
+	config_layout->addWidget(blockSizeLabel, 0, 4, 2, 1, Qt::AlignRight);
+
+	ComboBox *blockSizeCombo = new ComboBox(this, tr("FFT block bize"));
+	blockSizeCombo->setToolTip(tr("FFT block size"));
+	blockSizeCombo->setMinimumSize(100, 22);
+	blockSizeCombo->setMaximumSize(200, 22);
+	blockSizeCombo->setModel(&controls->m_blockSizeModel);
+	config_layout->addWidget(blockSizeCombo, 0, 5, 2, 1);
+	processor->reallocateBuffers();
+	connect(&controls->m_blockSizeModel, &ComboBoxModel::dataChanged, [=] {processor->reallocateBuffers();});
+
+	// FFT: window type: icon and selector
+	QLabel *windowLabel = new QLabel("", this);
+	QPixmap *windowIcon = new QPixmap(PLUGIN_NAME::getIconPixmap("window"));
+	windowIcon->setDevicePixelRatio(devicePixelRatio());
+	windowLabel->setPixmap(windowIcon->scaled(iconSize, Qt::IgnoreAspectRatio, Qt::SmoothTransformation));
+	config_layout->addWidget(windowLabel, 2, 4, 2, 1, Qt::AlignRight);
+
+	ComboBox *windowCombo = new ComboBox(this, tr("FFT window type"));
+	windowCombo->setToolTip(tr("FFT window type"));
+	windowCombo->setMinimumSize(100, 22);
+	windowCombo->setMaximumSize(200, 22);
+	windowCombo->setModel(&controls->m_windowModel);
+	config_layout->addWidget(windowCombo, 2, 5, 2, 1);
+	processor->rebuildWindow();
+	connect(&controls->m_windowModel, &ComboBoxModel::dataChanged, [=] {processor->rebuildWindow();});
+
+
+	// QSplitter middle and bottom: spectrum display widgets
+	m_spectrum = new SaSpectrumView(controls, processor, this);
+	display_splitter->addWidget(m_spectrum);
+
+	m_waterfall = new SaWaterfallView(controls, processor, this);
+	display_splitter->addWidget(m_waterfall);
+	m_waterfall->setVisible(m_controls->m_waterfallModel.value());
+	connect(&controls->m_waterfallModel, &BoolModel::dataChanged, [=] {m_waterfall->updateVisibility();});
+}
+
+
+// Suggest the best current widget size.
+QSize SaControlsDialog::sizeHint() const
+{
+	// Best width is determined by spectrum display sizeHint.
+	// Best height depends on whether waterfall is visible and
+	// consists of heights of the config section, spectrum, waterfall
+	// and some reserve for margins.
+	if (m_waterfall->isVisible())
+	{
+		return QSize(m_spectrum->sizeHint().width(),
+					 m_configHeight + m_spectrum->sizeHint().height() + m_waterfall->sizeHint().height() + 50);
+	}
+	else
+	{
+		return QSize(m_spectrum->sizeHint().width(),
+					 m_configHeight + m_spectrum->sizeHint().height() + 50);
+	}
+}
+

plugins/SpectrumAnalyzer/SaControlsDialog.h

@@ -0,0 +1,57 @@
+/*
+ * SaControlsDialog.h - declatation of SaControlsDialog class.
+ *
+ * Copyright (c) 2019 Martin Pavelek <he29/dot/HS/at/gmail/dot/com>
+ *
+ * This file is part of LMMS - https://lmms.io
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program (see COPYING); if not, write to the
+ * Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+ * Boston, MA 02110-1301 USA.
+ *
+ */
+
+#ifndef SACONTROLSDIALOG_H
+#define SACONTROLSDIALOG_H
+
+#include "EffectControlDialog.h"
+#include "SaControls.h"
+#include "SaSpectrumView.h"
+#include "SaProcessor.h"
+#include "SaWaterfallView.h"
+
+
+//! Top-level widget holding the configuration GUI and spectrum displays
+class SaControlsDialog : public EffectControlDialog
+{
+	Q_OBJECT
+public:
+	explicit SaControlsDialog(SaControls *controls, SaProcessor *processor);
+	virtual ~SaControlsDialog() {}
+
+	bool isResizable() const override {return true;}
+	QSize sizeHint() const override;
+
+private:
+	SaControls *m_controls;
+	SaProcessor *m_processor;
+
+	// Pointers to created widgets are needed to keep track of their sizeHint() changes.
+	// Config widget is a plain QWidget so it has just a fixed height instead.
+	const int m_configHeight = 75;
+	SaSpectrumView *m_spectrum;
+	SaWaterfallView *m_waterfall;
+};
+
+#endif // SACONTROLSDIALOG_H

plugins/SpectrumAnalyzer/SaProcessor.cpp

@@ -0,0 +1,571 @@
+/* SaProcessor.cpp - implementation of SaProcessor class.
+ *
+ * Copyright (c) 2019 Martin Pavelek <he29/dot/HS/at/gmail/dot/com>
+ *
+ * Based partially on Eq plugin code,
+ * Copyright (c) 2014-2017, David French <dave/dot/french3/at/googlemail/dot/com>
+ *
+ * This file is part of LMMS - https://lmms.io
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.	See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program (see COPYING); if not, write to the
+ * Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+ * Boston, MA 02110-1301 USA.
+ *
+ */
+
+#include "SaProcessor.h"
+
+#include <algorithm>
+#include <cmath>
+#include <iostream>
+#include <QMutexLocker>
+
+#include "lmms_math.h"
+
+
+SaProcessor::SaProcessor(SaControls *controls) :
+	m_controls(controls),
+	m_inBlockSize(FFT_BLOCK_SIZES[0]),
+	m_fftBlockSize(FFT_BLOCK_SIZES[0]),
+	m_sampleRate(Engine::mixer()->processingSampleRate()),
+	m_framesFilledUp(0),
+	m_spectrumActive(false),
+	m_waterfallActive(false),
+	m_waterfallNotEmpty(0),
+	m_reallocating(false)
+{
+	m_fftWindow.resize(m_inBlockSize, 1.0);
+	precomputeWindow(m_fftWindow.data(), m_inBlockSize, BLACKMAN_HARRIS);
+
+	m_bufferL.resize(m_fftBlockSize, 0);
+	m_bufferR.resize(m_fftBlockSize, 0);
+	m_spectrumL = (fftwf_complex *) fftwf_malloc(binCount() * sizeof (fftwf_complex));
+	m_spectrumR = (fftwf_complex *) fftwf_malloc(binCount() * sizeof (fftwf_complex));
+	m_fftPlanL = fftwf_plan_dft_r2c_1d(m_fftBlockSize, m_bufferL.data(), m_spectrumL, FFTW_MEASURE);
+	m_fftPlanR = fftwf_plan_dft_r2c_1d(m_fftBlockSize, m_bufferR.data(), m_spectrumR, FFTW_MEASURE);
+
+	m_absSpectrumL.resize(binCount(), 0);
+	m_absSpectrumR.resize(binCount(), 0);
+	m_normSpectrumL.resize(binCount(), 0);
+	m_normSpectrumR.resize(binCount(), 0);
+
+	m_history.resize(binCount() * m_waterfallHeight * sizeof qRgb(0,0,0), 0);
+
+	clear();
+}
+
+
+SaProcessor::~SaProcessor()
+{
+	if (m_fftPlanL != NULL) {fftwf_destroy_plan(m_fftPlanL);}
+	if (m_fftPlanR != NULL) {fftwf_destroy_plan(m_fftPlanR);}
+	if (m_spectrumL != NULL) {fftwf_free(m_spectrumL);}
+	if (m_spectrumR != NULL) {fftwf_free(m_spectrumR);}
+
+	m_fftPlanL = NULL;
+	m_fftPlanR = NULL;
+	m_spectrumL = NULL;
+	m_spectrumR = NULL;
+}
+
+
+// Load a batch of data from LMMS; run FFT analysis if buffer is full enough.
+void SaProcessor::analyse(sampleFrame *in_buffer, const fpp_t frame_count)
+{
+	#ifdef SA_DEBUG
+		int start_time = std::chrono::high_resolution_clock::now().time_since_epoch().count();
+	#endif
+	// only take in data if any view is visible and not paused
+	if ((m_spectrumActive || m_waterfallActive) && !m_controls->m_pauseModel.value())
+	{
+		const bool stereo = m_controls->m_stereoModel.value();
+		fpp_t in_frame = 0;
+		while (in_frame < frame_count)
+		{
+			// fill sample buffers and check for zero input
+			bool block_empty = true;
+			for (; in_frame < frame_count && m_framesFilledUp < m_inBlockSize; in_frame++, m_framesFilledUp++)
+			{
+				if (stereo)
+				{
+					m_bufferL[m_framesFilledUp] = in_buffer[in_frame][0];
+					m_bufferR[m_framesFilledUp] = in_buffer[in_frame][1];
+				}
+				else
+				{
+					m_bufferL[m_framesFilledUp] =
+					m_bufferR[m_framesFilledUp] = (in_buffer[in_frame][0] + in_buffer[in_frame][1]) * 0.5f;
+				}
+				if (in_buffer[in_frame][0] != 0.f || in_buffer[in_frame][1] != 0.f)
+				{
+					block_empty = false;
+				}
+			}
+	
+			// Run analysis only if buffers contain enough data.
+			// Also, to prevent audio interruption and a momentary GUI freeze,
+			// skip analysis if buffers are being reallocated.
+			if (m_framesFilledUp < m_inBlockSize || m_reallocating) {return;}
+
+			// update sample rate
+			m_sampleRate = Engine::mixer()->processingSampleRate();
+	
+			// apply FFT window
+			for (unsigned int i = 0; i < m_inBlockSize; i++)
+			{
+				m_bufferL[i] = m_bufferL[i] * m_fftWindow[i];
+				m_bufferR[i] = m_bufferR[i] * m_fftWindow[i];
+			}
+	
+			// lock data shared with SaSpectrumView and SaWaterfallView
+			QMutexLocker lock(&m_dataAccess);
+
+			// Run FFT on left channel, convert the result to absolute magnitude
+			// spectrum and normalize it.
+			fftwf_execute(m_fftPlanL);
+			absspec(m_spectrumL, m_absSpectrumL.data(), binCount());
+			normalize(m_absSpectrumL, m_normSpectrumL, m_inBlockSize);
+	
+			// repeat analysis for right channel if stereo processing is enabled
+			if (stereo)
+			{
+				fftwf_execute(m_fftPlanR);
+				absspec(m_spectrumR, m_absSpectrumR.data(), binCount());
+				normalize(m_absSpectrumR, m_normSpectrumR, m_inBlockSize);
+			}
+
+			// count empty lines so that empty history does not have to update
+			if (block_empty && m_waterfallNotEmpty)
+			{
+				m_waterfallNotEmpty -= 1;
+			}
+			else if (!block_empty)
+			{
+				m_waterfallNotEmpty = m_waterfallHeight + 2;
+			}
+
+			if (m_waterfallActive && m_waterfallNotEmpty)
+			{
+				// move waterfall history one line down and clear the top line
+				QRgb *pixel = (QRgb *)m_history.data();
+				std::copy(pixel,
+						  pixel + binCount() * m_waterfallHeight - binCount(),
+						  pixel + binCount());
+				memset(pixel, 0, binCount() * sizeof (QRgb));
+
+				// add newest result on top
+				int target;		// pixel being constructed
+				float accL = 0;	// accumulators for merging multiple bins
+				float accR = 0;
+	
+				for (unsigned int i = 0; i < binCount(); i++)
+				{
+					// Every frequency bin spans a frequency range that must be
+					// partially or fully mapped to a pixel. Any inconsistency
+					// may be seen in the spectrogram as dark or white lines --
+					// play white noise to confirm your change did not break it.
+					float band_start = freqToXPixel(binToFreq(i) - binBandwidth() / 2.0, binCount());
+					float band_end = freqToXPixel(binToFreq(i + 1) - binBandwidth() / 2.0, binCount());
+					if (m_controls->m_logXModel.value())
+					{
+						// Logarithmic scale
+						if (band_end - band_start > 1.0)
+						{
+							// band spans multiple pixels: draw all pixels it covers
+							for (target = (int)band_start; target < (int)band_end; target++)
+							{
+								if (target >= 0 && target < binCount())
+								{
+									pixel[target] = makePixel(m_normSpectrumL[i], m_normSpectrumR[i]);
+								}
+							}
+							// save remaining portion of the band for the following band / pixel
+							// (in case the next band uses sub-pixel drawing)
+							accL = (band_end - (int)band_end) * m_normSpectrumL[i];
+							accR = (band_end - (int)band_end) * m_normSpectrumR[i];
+						}
+						else
+						{
+							// sub-pixel drawing; add contribution of current band
+							target = (int)band_start;
+							if ((int)band_start == (int)band_end)
+							{
+								// band ends within current target pixel, accumulate
+								accL += (band_end - band_start) * m_normSpectrumL[i];
+								accR += (band_end - band_start) * m_normSpectrumR[i];
+							}
+							else
+							{
+								// Band ends in the next pixel -- finalize the current pixel.
+								// Make sure contribution is split correctly on pixel boundary.
+								accL += ((int)band_end - band_start) * m_normSpectrumL[i];
+								accR += ((int)band_end - band_start) * m_normSpectrumR[i];
+	
+								if (target >= 0 && target < binCount()) {pixel[target] = makePixel(accL, accR);}
+
+								// save remaining portion of the band for the following band / pixel
+								accL = (band_end - (int)band_end) * m_normSpectrumL[i];
+								accR = (band_end - (int)band_end) * m_normSpectrumR[i];
+							}
+						}
+					}
+					else
+					{
+						// Linear: always draws one or more pixels per band
+						for (target = (int)band_start; target < band_end; target++)
+						{
+							if (target >= 0 && target < binCount())
+							{
+								pixel[target] = makePixel(m_normSpectrumL[i], m_normSpectrumR[i]);
+							}
+						}
+					}
+				}
+			}
+			#ifdef SA_DEBUG
+				// report FFT processing speed
+				start_time = std::chrono::high_resolution_clock::now().time_since_epoch().count() - start_time;
+				std::cout << "Processed " << m_framesFilledUp << " samples in " << start_time / 1000000.0 << " ms" << std::endl;
+			#endif
+
+			// clean up before checking for more data from input buffer
+			m_framesFilledUp = 0;
+		}
+	}
+}
+
+
+// Produce a spectrogram pixel from normalized spectrum data.
+// Values over 1.0 will cause the color components to overflow: this is left
+// intentionally untreated as it clearly indicates which frequency is clipping.
+// Gamma correction is applied to make small values more visible and to make
+// a linear gradient actually appear roughly linear. The correction should be
+// around 0.42 to 0.45 for sRGB displays (or lower for bigger visibility boost).
+QRgb SaProcessor::makePixel(float left, float right, float gamma_correction) const
+{
+	if (m_controls->m_stereoModel.value())
+	{
+		float ampL = pow(left, gamma_correction);
+		float ampR = pow(right, gamma_correction);
+		return qRgb(m_controls->m_colorL.red() * ampL + m_controls->m_colorR.red() * ampR,
+					m_controls->m_colorL.green() * ampL + m_controls->m_colorR.green() * ampR,
+					m_controls->m_colorL.blue() * ampL + m_controls->m_colorR.blue() * ampR);
+	}
+	else
+	{
+		float ampL = pow(left, gamma_correction);
+		// make mono color brighter to compensate for the fact it is not summed
+		return qRgb(m_controls->m_colorMono.lighter().red() * ampL,
+					m_controls->m_colorMono.lighter().green() * ampL,
+					m_controls->m_colorMono.lighter().blue() * ampL);
+	}
+}
+
+
+
+// Inform the processor whether any display widgets actually need it.
+void SaProcessor::setSpectrumActive(bool active)
+{
+	m_spectrumActive = active;
+}
+
+void SaProcessor::setWaterfallActive(bool active)
+{
+	m_waterfallActive = active;
+}
+
+
+// Reallocate data buffers according to newly set block size.
+void SaProcessor::reallocateBuffers()
+{
+	unsigned int new_size_index = m_controls->m_blockSizeModel.value();
+	unsigned int new_in_size, new_fft_size;
+	unsigned int new_bins;
+
+	// get new block sizes and bin count based on selected index
+	if (new_size_index < FFT_BLOCK_SIZES.size())
+	{
+		new_in_size = FFT_BLOCK_SIZES[new_size_index];
+	}
+	else
+	{
+		new_in_size = FFT_BLOCK_SIZES.back();
+	}
+	if (new_size_index + m_zeroPadFactor < FFT_BLOCK_SIZES.size())
+	{
+		new_fft_size = FFT_BLOCK_SIZES[new_size_index + m_zeroPadFactor];
+	}
+	else
+	{
+		new_fft_size = FFT_BLOCK_SIZES.back();
+	}
+
+	new_bins = new_fft_size / 2 +1;
+
+	// Lock data shared with SaSpectrumView and SaWaterfallView.
+	// The m_reallocating is here to tell analyse() to avoid asking for the
+	// lock, since fftw3 can take a while to find the fastest FFT algorithm
+	// for given machine, which would produce interruption in the audio stream.
+	m_reallocating = true;
+	QMutexLocker lock(&m_dataAccess);
+
+	// destroy old FFT plan and free the result buffer
+	if (m_fftPlanL != NULL) {fftwf_destroy_plan(m_fftPlanL);}
+	if (m_fftPlanR != NULL) {fftwf_destroy_plan(m_fftPlanR);}
+	if (m_spectrumL != NULL) {fftwf_free(m_spectrumL);}
+	if (m_spectrumR != NULL) {fftwf_free(m_spectrumR);}
+
+	// allocate new space, create new plan and resize containers
+	m_fftWindow.resize(new_in_size, 1.0);
+	precomputeWindow(m_fftWindow.data(), new_in_size, (FFT_WINDOWS) m_controls->m_windowModel.value());
+	m_bufferL.resize(new_fft_size, 0);
+	m_bufferR.resize(new_fft_size, 0);
+	m_spectrumL = (fftwf_complex *) fftwf_malloc(new_bins * sizeof (fftwf_complex));
+	m_spectrumR = (fftwf_complex *) fftwf_malloc(new_bins * sizeof (fftwf_complex));
+	m_fftPlanL = fftwf_plan_dft_r2c_1d(new_fft_size, m_bufferL.data(), m_spectrumL, FFTW_MEASURE);
+	m_fftPlanR = fftwf_plan_dft_r2c_1d(new_fft_size, m_bufferR.data(), m_spectrumR, FFTW_MEASURE);
+
+	if (m_fftPlanL == NULL || m_fftPlanR == NULL)
+	{
+		std::cerr << "Failed to create new FFT plan!" << std::endl;
+	}
+	m_absSpectrumL.resize(new_bins, 0);
+	m_absSpectrumR.resize(new_bins, 0);
+	m_normSpectrumL.resize(new_bins, 0);
+	m_normSpectrumR.resize(new_bins, 0);
+
+	m_history.resize(new_bins * m_waterfallHeight * sizeof qRgb(0,0,0), 0);
+
+	// done; publish new sizes and clean up
+	m_inBlockSize = new_in_size;
+	m_fftBlockSize = new_fft_size;
+
+	lock.unlock();
+	m_reallocating = false;
+	clear();
+}
+
+
+// Precompute a new FFT window based on currently selected type.
+void SaProcessor::rebuildWindow()
+{
+	// computation is done in fft_helpers
+	QMutexLocker lock(&m_dataAccess);
+	precomputeWindow(m_fftWindow.data(), m_inBlockSize, (FFT_WINDOWS) m_controls->m_windowModel.value());
+}
+
+
+// Clear all data buffers and replace contents with zeros.
+// Note: may take a few milliseconds, do not call in a loop!
+void SaProcessor::clear()
+{
+	QMutexLocker lock(&m_dataAccess);
+	m_framesFilledUp = 0;
+	std::fill(m_bufferL.begin(), m_bufferL.end(), 0);
+	std::fill(m_bufferR.begin(), m_bufferR.end(), 0);
+	std::fill(m_absSpectrumL.begin(), m_absSpectrumL.end(), 0);
+	std::fill(m_absSpectrumR.begin(), m_absSpectrumR.end(), 0);
+	std::fill(m_normSpectrumL.begin(), m_normSpectrumL.end(), 0);
+	std::fill(m_normSpectrumR.begin(), m_normSpectrumR.end(), 0);
+	std::fill(m_history.begin(), m_history.end(), 0);
+}
+
+
+// --------------------------------------
+// Frequency conversion helpers
+//
+
+// Get sample rate value that is valid for currently stored results.
+unsigned int SaProcessor::getSampleRate() const
+{
+	return m_sampleRate;
+}
+
+
+// Maximum frequency of a sampled signal is equal to half of its sample rate.
+float SaProcessor::getNyquistFreq() const
+{
+	return getSampleRate() / 2.0f;
+}
+
+
+// FFTW automatically discards upper half of the symmetric FFT output, so
+// the useful bin count is the transform size divided by 2, plus zero.
+unsigned int SaProcessor::binCount() const
+{
+	return m_fftBlockSize / 2 + 1;
+}
+
+
+// Return the center frequency of given frequency bin.
+float SaProcessor::binToFreq(unsigned int bin_index) const
+{
+	return getNyquistFreq() * bin_index / binCount();
+}
+
+
+// Return width of the frequency range that falls into one bin.
+// The binCount is lowered by one since half of the first and last bin is
+// actually outside the frequency range.
+float SaProcessor::binBandwidth() const
+{
+	return getNyquistFreq() / (binCount() - 1);
+}
+
+
+float SaProcessor::getFreqRangeMin(bool linear) const
+{
+	switch (m_controls->m_freqRangeModel.value())
+	{
+		case FRANGE_AUDIBLE: return FRANGE_AUDIBLE_START;
+		case FRANGE_BASS: return FRANGE_BASS_START;
+		case FRANGE_MIDS: return FRANGE_MIDS_START;
+		case FRANGE_HIGH: return FRANGE_HIGH_START;
+		default:
+		case FRANGE_FULL: return linear ? 0 : LOWEST_LOG_FREQ;
+	}
+}
+
+
+float SaProcessor::getFreqRangeMax() const
+{
+	switch (m_controls->m_freqRangeModel.value())
+	{
+		case FRANGE_AUDIBLE: return FRANGE_AUDIBLE_END;
+		case FRANGE_BASS: return FRANGE_BASS_END;
+		case FRANGE_MIDS: return FRANGE_MIDS_END;
+		case FRANGE_HIGH: return FRANGE_HIGH_END;
+		default:
+		case FRANGE_FULL: return getNyquistFreq();
+	}
+}
+
+
+// Map frequency to pixel x position on a display of given width.
+float SaProcessor::freqToXPixel(float freq, unsigned int width) const
+{
+	if (m_controls->m_logXModel.value())
+	{
+		if (freq <= 1) {return 0;}
+		float min = log10(getFreqRangeMin());
+		float range = log10(getFreqRangeMax()) - min;
+		return (log10(freq) - min) / range * width;
+	}
+	else
+	{
+		float min = getFreqRangeMin();
+		float range = getFreqRangeMax() - min;
+		return (freq - min) / range * width;
+	}
+}
+
+
+// Map pixel x position on display of given width back to frequency.
+float SaProcessor::xPixelToFreq(float x, unsigned int width) const
+{
+	if (m_controls->m_logXModel.value())
+	{
+		float min = log10(getFreqRangeMin());
+		float max = log10(getFreqRangeMax());
+		float range = max - min;
+		return pow(10, min + x / width * range);
+	}
+	else
+	{
+		float min = getFreqRangeMin();
+		float range = getFreqRangeMax() - min;
+		return min + x / width * range;
+	}
+}
+
+
+// --------------------------------------
+// Amplitude conversion helpers
+//
+float SaProcessor::getAmpRangeMin(bool linear) const
+{
+	// return very low limit to make sure zero gets included at linear grid
+	if (linear) {return -900;}
+	switch (m_controls->m_ampRangeModel.value())
+	{
+		case ARANGE_EXTENDED: return ARANGE_EXTENDED_START;
+		case ARANGE_AUDIBLE: return ARANGE_AUDIBLE_START;
+		case ARANGE_NOISE: return ARANGE_NOISE_START;
+		default:
+		case ARANGE_DEFAULT: return ARANGE_DEFAULT_START;
+	}
+}
+
+
+float SaProcessor::getAmpRangeMax() const
+{
+	switch (m_controls->m_ampRangeModel.value())
+	{
+		case ARANGE_EXTENDED: return ARANGE_EXTENDED_END;
+		case ARANGE_AUDIBLE: return ARANGE_AUDIBLE_END;
+		case ARANGE_NOISE: return ARANGE_NOISE_END;
+		default:
+		case ARANGE_DEFAULT: return ARANGE_DEFAULT_END;
+	}
+}
+
+
+// Map linear amplitude to pixel y position on a display of given height.
+// Note that display coordinates are flipped: amplitude grows from [height] to zero.
+float SaProcessor::ampToYPixel(float amplitude, unsigned int height) const
+{
+	if (m_controls->m_logYModel.value())
+	{
+		// logarithmic scale: convert linear amplitude to dB (relative to 1.0)
+		float amplitude_dB = 10 * log10(amplitude);
+		if (amplitude_dB < getAmpRangeMin())
+		{
+			return height;
+		}
+		else
+		{
+			float max = getAmpRangeMax();
+			float range = getAmpRangeMin() - max;
+			return (amplitude_dB - max) / range * height;
+		}
+	}
+	else
+	{
+		// linear scale: convert returned ranges from dB to linear scale
+		float max = pow(10, getAmpRangeMax() / 10);
+		float range = pow(10, getAmpRangeMin() / 10) - max;
+		return (amplitude - max) / range * height;
+	}
+}
+
+
+// Map pixel y position on display of given height back to amplitude.
+// Note that display coordinates are flipped: amplitude grows from [height] to zero.
+// Also note that in logarithmic Y mode the returned amplitude is in dB, not linear.
+float SaProcessor::yPixelToAmp(float y, unsigned int height) const
+{
+	if (m_controls->m_logYModel.value())
+	{
+		float max = getAmpRangeMax();
+		float range = getAmpRangeMin() - max;
+		return max + range * (y / height);
+	}
+	else
+	{
+		// linear scale: convert returned ranges from dB to linear scale
+		float max = pow(10, getAmpRangeMax() / 10);
+		float range = pow(10, getAmpRangeMin() / 10) - max;
+		return max + range * (y / height);
+	}
+}
+

plugins/SpectrumAnalyzer/SaProcessor.h

@@ -0,0 +1,122 @@
+/* SaProcessor.h - declaration of SaProcessor class.
+ *
+ * Copyright (c) 2019 Martin Pavelek <he29/dot/HS/at/gmail/dot/com>
+ *
+ * Based partially on Eq plugin code,
+ * Copyright (c) 2014 David French <dave/dot/french3/at/googlemail/dot/com>
+ *
+ * This file is part of LMMS - https://lmms.io
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program (see COPYING); if not, write to the
+ * Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+ * Boston, MA 02110-1301 USA.
+ *
+ */
+
+#ifndef SAPROCESSOR_H
+#define SAPROCESSOR_H
+
+#include <QColor>
+#include <QMutex>
+#include <vector>
+
+#include "fft_helpers.h"
+#include "SaControls.h"
+
+
+//! Receives audio data, runs FFT analysis and stores the result.
+class SaProcessor
+{
+public:
+	explicit SaProcessor(SaControls *controls);
+	virtual ~SaProcessor();
+
+	void analyse(sampleFrame *in_buffer, const fpp_t frame_count);
+
+	// inform processor if any processing is actually required
+	void setSpectrumActive(bool active);
+	void setWaterfallActive(bool active);
+
+	// configuration is taken from models in SaControls; some changes require
+	// an exlicit update request (reallocation and window rebuild)
+	void reallocateBuffers();
+	void rebuildWindow();
+	void clear();
+
+	// information about results and unit conversion helpers
+	float binToFreq(unsigned int bin_index) const;
+	float binBandwidth() const;
+
+	float freqToXPixel(float frequency, unsigned int width) const;
+	float xPixelToFreq(float x, unsigned int width) const;
+
+	float ampToYPixel(float amplitude, unsigned int height) const;
+	float yPixelToAmp(float y, unsigned int height) const;
+
+	unsigned int getSampleRate() const;
+	float getNyquistFreq() const;
+
+	float getFreqRangeMin(bool linear = false) const;
+	float getFreqRangeMax() const;
+	float getAmpRangeMin(bool linear = false) const;
+	float getAmpRangeMax() const;
+
+	// data access lock must be acquired by any friendly class that touches
+	// the results, mainly to prevent unexpected mid-way reallocation
+	QMutex m_dataAccess;
+
+private:
+	SaControls *m_controls;
+
+	// currently valid configuration
+	const unsigned int m_zeroPadFactor = 2;	//!< use n-steps bigger FFT for given block size
+	unsigned int m_inBlockSize;				//!< size of input (time domain) data block
+	unsigned int m_fftBlockSize;			//!< size of padded block for FFT processing
+	unsigned int m_sampleRate;
+
+	unsigned int binCount() const;			//!< size of output (frequency domain) data block
+
+	// data buffers (roughly in the order of processing, from input to output)
+	unsigned int m_framesFilledUp;
+	std::vector<float> m_bufferL;			//!< time domain samples (left)
+	std::vector<float> m_bufferR;			//!< time domain samples (right)
+	std::vector<float> m_fftWindow;			//!< precomputed window function coefficients
+	fftwf_plan m_fftPlanL;
+	fftwf_plan m_fftPlanR;
+	fftwf_complex *m_spectrumL;				//!< frequency domain samples (complex) (left)
+	fftwf_complex *m_spectrumR;				//!< frequency domain samples (complex) (right)
+	std::vector<float> m_absSpectrumL;		//!< frequency domain samples (absolute) (left)
+	std::vector<float> m_absSpectrumR;		//!< frequency domain samples (absolute) (right)
+	std::vector<float> m_normSpectrumL;		//!< frequency domain samples (normalized) (left)
+	std::vector<float> m_normSpectrumR;     //!< frequency domain samples (normalized) (right)
+
+	// spectrum history for waterfall: new normSpectrum lines are added on top
+	std::vector<uchar> m_history;
+	const unsigned int m_waterfallHeight = 200;	// Number of stored lines.
+												// Note: high values may make it harder to see transients.
+
+	// book keeping
+	bool m_spectrumActive;
+	bool m_waterfallActive;
+	unsigned int m_waterfallNotEmpty;
+	bool m_reallocating;
+
+	// merge L and R channels and apply gamma correction to make a spectrogram pixel
+	QRgb makePixel(float left, float right, float gamma_correction = 0.30) const;
+
+	friend class SaSpectrumView;
+	friend class SaWaterfallView;
+};
+#endif // SAPROCESSOR_H
+

plugins/SpectrumAnalyzer/SaSpectrumView.cpp

@@ -0,0 +1,796 @@
+/* SaSpectrumView.cpp - implementation of SaSpectrumView class.
+ *
+ * Copyright (c) 2019 Martin Pavelek <he29/dot/HS/at/gmail/dot/com>
+ *
+ * Based partially on Eq plugin code,
+ * Copyright (c) 2014-2017, David French <dave/dot/french3/at/googlemail/dot/com>
+ *
+ * This file is part of LMMS - https://lmms.io
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.	See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program (see COPYING); if not, write to the
+ * Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+ * Boston, MA 02110-1301 USA.
+ *
+ */
+
+#include "SaSpectrumView.h"
+
+#include <algorithm>
+#include <cmath>
+#include <QMouseEvent>
+#include <QMutexLocker>
+#include <QPainter>
+#include <QString>
+
+#include "GuiApplication.h"
+#include "MainWindow.h"
+#include "SaProcessor.h"
+
+#ifdef SA_DEBUG
+	#include <chrono>
+	#include <iostream>
+#endif
+
+
+SaSpectrumView::SaSpectrumView(SaControls *controls, SaProcessor *processor, QWidget *_parent) :
+	QWidget(_parent),
+	m_controls(controls),
+	m_processor(processor),
+	m_freezeRequest(false),
+	m_frozen(false)
+{
+	setMinimumSize(360, 170);
+	setSizePolicy(QSizePolicy::Minimum, QSizePolicy::Minimum);
+
+	connect(gui->mainWindow(), SIGNAL(periodicUpdate()), this, SLOT(periodicUpdate()));
+
+	m_displayBufferL.resize(m_processor->binCount(), 0);
+	m_displayBufferR.resize(m_processor->binCount(), 0);
+	m_peakBufferL.resize(m_processor->binCount(), 0);
+	m_peakBufferR.resize(m_processor->binCount(), 0);
+
+	m_freqRangeIndex = m_controls->m_freqRangeModel.value();
+	m_ampRangeIndex = m_controls->m_ampRangeModel.value();
+
+	m_logFreqTics = makeLogFreqTics(m_processor->getFreqRangeMin(), m_processor->getFreqRangeMax());
+	m_linearFreqTics = makeLinearFreqTics(m_processor->getFreqRangeMin(), m_processor->getFreqRangeMax());
+	m_logAmpTics = makeLogAmpTics(m_processor->getAmpRangeMin(), m_processor->getAmpRangeMax());
+	m_linearAmpTics = makeLinearAmpTics(m_processor->getAmpRangeMin(), m_processor->getAmpRangeMax());
+
+	m_cursor = QPoint(0, 0);
+}
+
+
+// Compose and draw all the content; periodically called by Qt.
+// NOTE: Performance sensitive! If the drawing takes too long, it will drag
+// the FPS down for the entire program! Use SA_DEBUG to display timings.
+void SaSpectrumView::paintEvent(QPaintEvent *event)
+{
+	#ifdef SA_DEBUG
+		int total_time = std::chrono::high_resolution_clock::now().time_since_epoch().count();
+	#endif
+
+	// 0) Constants and init
+	QPainter painter(this);
+	painter.setRenderHint(QPainter::Antialiasing, true);
+
+	// drawing and path-making are split into multiple methods for clarity;
+	// display boundaries are updated here and shared as member variables
+	m_displayTop = 1;
+	m_displayBottom = height() -20;
+	m_displayLeft = 26;
+	m_displayRight = width() -26;
+	m_displayWidth = m_displayRight - m_displayLeft;
+
+	// recompute range labels if needed
+	if (m_freqRangeIndex != m_controls->m_freqRangeModel.value())
+	{
+		m_logFreqTics = makeLogFreqTics(m_processor->getFreqRangeMin(), m_processor->getFreqRangeMax());
+		m_linearFreqTics = makeLinearFreqTics(m_processor->getFreqRangeMin(true), m_processor->getFreqRangeMax());
+		m_freqRangeIndex = m_controls->m_freqRangeModel.value();
+	}
+	if (m_ampRangeIndex != m_controls->m_ampRangeModel.value())
+	{
+		m_logAmpTics = makeLogAmpTics(m_processor->getAmpRangeMin(), m_processor->getAmpRangeMax());
+		m_linearAmpTics = makeLinearAmpTics(m_processor->getAmpRangeMin(true), m_processor->getAmpRangeMax());
+		m_ampRangeIndex = m_controls->m_ampRangeModel.value();
+	}
+
+	// generate freeze request or clear "frozen" status based on freeze button
+	if (!m_frozen && m_controls->m_refFreezeModel.value())
+	{
+		m_freezeRequest = true;
+	}
+	else if (!m_controls->m_refFreezeModel.value())
+	{
+		m_frozen = false;
+	}
+
+	// 1) Background, grid and labels
+	drawGrid(painter);
+
+	// 2) Spectrum display
+	drawSpectrum(painter);
+
+	// 3) Overlays
+	// draw cursor (if it is within bounds)
+	drawCursor(painter);
+
+	// always draw the display outline
+	painter.setPen(QPen(m_controls->m_colorGrid, 2, Qt::SolidLine, Qt::RoundCap, Qt::BevelJoin));
+	painter.drawRoundedRect(m_displayLeft, 1,
+							m_displayWidth, m_displayBottom,
+							2.0, 2.0);
+
+	#ifdef SA_DEBUG
+		// display what FPS would be achieved if spectrum display ran in a loop
+		total_time = std::chrono::high_resolution_clock::now().time_since_epoch().count() - total_time;
+		painter.setPen(QPen(m_controls->m_colorLabels, 1,
+							Qt::SolidLine, Qt::RoundCap, Qt::BevelJoin));
+		painter.drawText(m_displayRight -100, 70, 100, 16, Qt::AlignLeft,
+						 QString(std::string("Max FPS: " + std::to_string(1000000000.0 / total_time)).c_str()));
+	#endif
+}
+
+
+// Refresh data and draw the spectrum.
+void SaSpectrumView::drawSpectrum(QPainter &painter)
+{
+	#ifdef SA_DEBUG
+		int path_time = 0, draw_time = 0;
+	#endif
+
+	// draw the graph only if there is any input, averaging residue or peaks
+	QMutexLocker lock(&m_processor->m_dataAccess);
+	if (m_decaySum > 0 || notEmpty(m_processor->m_normSpectrumL) || notEmpty(m_processor->m_normSpectrumR))
+	{
+		lock.unlock();
+		#ifdef SA_DEBUG
+			path_time = std::chrono::high_resolution_clock::now().time_since_epoch().count();
+		#endif
+		// update data buffers and reconstruct paths
+		refreshPaths();
+		#ifdef SA_DEBUG
+			path_time = std::chrono::high_resolution_clock::now().time_since_epoch().count() - path_time;
+		#endif
+
+		// draw stored paths
+		#ifdef SA_DEBUG
+			draw_time = std::chrono::high_resolution_clock::now().time_since_epoch().count();
+		#endif
+		// in case stereo is disabled, mono data are stored in left channel structures
+		if (m_controls->m_stereoModel.value())
+		{
+			painter.fillPath(m_pathR, QBrush(m_controls->m_colorR));
+			painter.fillPath(m_pathL, QBrush(m_controls->m_colorL));
+		}
+		else
+		{
+			painter.fillPath(m_pathL, QBrush(m_controls->m_colorMono));
+		}
+		// draw the peakBuffer only if peak hold or reference freeze is active
+		if (m_controls->m_peakHoldModel.value() || m_controls->m_refFreezeModel.value())
+		{
+			if (m_controls->m_stereoModel.value())
+			{
+				painter.setPen(QPen(m_controls->m_colorR, 1, Qt::SolidLine, Qt::RoundCap, Qt::BevelJoin));
+				painter.drawPath(m_pathPeakR);
+				painter.setPen(QPen(m_controls->m_colorL, 1, Qt::SolidLine, Qt::RoundCap, Qt::BevelJoin));
+				painter.drawPath(m_pathPeakL);
+			}
+			else
+			{
+				painter.setPen(QPen(m_controls->m_colorL, 1, Qt::SolidLine, Qt::RoundCap, Qt::BevelJoin));
+				painter.drawPath(m_pathPeakL);
+			}
+		}
+		#ifdef SA_DEBUG
+			draw_time = std::chrono::high_resolution_clock::now().time_since_epoch().count() - draw_time;
+		#endif
+	}
+	else
+	{
+		lock.unlock();
+	}
+
+	#ifdef SA_DEBUG
+		// display measurement results
+		painter.drawText(m_displayRight -100, 90, 100, 16, Qt::AlignLeft,
+						 QString(std::string("Path ms: " + std::to_string(path_time / 1000000.0)).c_str()));
+		painter.drawText(m_displayRight -100, 110, 100, 16, Qt::AlignLeft,
+						 QString(std::string("Draw ms: " + std::to_string(draw_time / 1000000.0)).c_str()));
+	#endif
+}
+
+
+// Read newest FFT results from SaProcessor, update local display buffers
+// and build QPainter paths.
+void SaSpectrumView::refreshPaths()
+{
+	// Lock is required for the entire function, mainly to prevent block size
+	// changes from causing reallocation of data structures mid-way.
+	QMutexLocker lock(&m_processor->m_dataAccess);
+
+	// check if bin count changed and reallocate display buffers accordingly
+	if (m_processor->binCount() != m_displayBufferL.size())
+	{
+		m_displayBufferL.clear();
+		m_displayBufferR.clear();
+		m_peakBufferL.clear();
+		m_peakBufferR.clear();
+		m_displayBufferL.resize(m_processor->binCount(), 0);
+		m_displayBufferR.resize(m_processor->binCount(), 0);
+		m_peakBufferL.resize(m_processor->binCount(), 0);
+		m_peakBufferR.resize(m_processor->binCount(), 0);
+	}
+
+	// update display buffers for left and right channel
+	#ifdef SA_DEBUG
+		int refresh_time = std::chrono::high_resolution_clock::now().time_since_epoch().count();
+	#endif
+	m_decaySum = 0;
+	updateBuffers(m_processor->m_normSpectrumL.data(), m_displayBufferL.data(), m_peakBufferL.data());
+	updateBuffers(m_processor->m_normSpectrumR.data(), m_displayBufferR.data(), m_peakBufferR.data());
+	#ifdef SA_DEBUG
+		refresh_time = std::chrono::high_resolution_clock::now().time_since_epoch().count() - refresh_time;
+	#endif
+
+	// if there was a freeze request, it was taken care of during the update
+	if (m_controls->m_refFreezeModel.value() && m_freezeRequest)
+	{
+		m_freezeRequest = false;
+		m_frozen = true;
+	}
+
+	#ifdef SA_DEBUG
+		int make_time = std::chrono::high_resolution_clock::now().time_since_epoch().count();
+	#endif
+	// Use updated display buffers to prepare new paths for QPainter.
+	// This is the second slowest action (first is the subsequent drawing); use
+	// the resolution parameter to balance display quality and performance.
+	m_pathL = makePath(m_displayBufferL, 1.5);
+	if (m_controls->m_stereoModel.value())
+	{
+		m_pathR = makePath(m_displayBufferR, 1.5);
+	}
+	if (m_controls->m_peakHoldModel.value() || m_controls->m_refFreezeModel.value())
+	{
+		m_pathPeakL = makePath(m_peakBufferL, 0.25);
+		if (m_controls->m_stereoModel.value())
+		{
+			m_pathPeakR = makePath(m_peakBufferR, 0.25);
+		}
+	}
+	#ifdef SA_DEBUG
+		make_time = std::chrono::high_resolution_clock::now().time_since_epoch().count() - make_time;
+	#endif
+
+	#ifdef SA_DEBUG
+		// print measurement results
+		std::cout << "Buffer update ms: " << std::to_string(refresh_time / 1000000.0) << ", ";
+		std::cout << "Path-make ms: " << std::to_string(make_time / 1000000.0) << std::endl;
+	#endif
+}
+
+
+// Update display buffers: add new data, update average and peaks / reference.
+// Output the sum of all displayed values -- draw only if it is non-zero.
+// NOTE: The calling function is responsible for acquiring SaProcessor data
+// access lock!
+void SaSpectrumView::updateBuffers(float *spectrum, float *displayBuffer, float *peakBuffer)
+{
+	for (int n = 0; n < m_processor->binCount(); n++)
+	{
+		// Update the exponential average if enabled, or simply copy the value.
+		if (!m_controls->m_pauseModel.value())
+		{
+			if (m_controls->m_smoothModel.value())
+			{
+				displayBuffer[n] = spectrum[n] * m_smoothFactor + displayBuffer[n] * (1 - m_smoothFactor);
+			}
+			else
+			{
+				displayBuffer[n] = spectrum[n];
+			}
+		}
+		// Update peak-hold and reference freeze data (using a shared curve).
+		// Peak hold and freeze can be combined: decay only if not frozen.
+		// Ref. freeze operates on the (possibly averaged) display buffer.
+		if (m_controls->m_refFreezeModel.value() && m_freezeRequest)
+		{
+			peakBuffer[n] = displayBuffer[n];
+		}
+		else if (m_controls->m_peakHoldModel.value() && !m_controls->m_pauseModel.value())
+		{
+			if (spectrum[n] > peakBuffer[n])
+			{
+				peakBuffer[n] = spectrum[n];
+			}
+			else if (!m_controls->m_refFreezeModel.value())
+			{
+				peakBuffer[n] = peakBuffer[n] * m_peakDecayFactor;
+			}
+		}
+		else if (!m_controls->m_refFreezeModel.value() && !m_controls->m_peakHoldModel.value())
+		{
+			peakBuffer[n] = 0;
+		}
+		// take note if there was actually anything to display
+		m_decaySum += displayBuffer[n] + peakBuffer[n];
+	}
+}
+
+
+// Use display buffer to build a path that can be drawn or filled by QPainter.
+// Resolution controls the performance / quality tradeoff; the value specifies
+// number of points in x axis per device pixel. Values over 1.0 still
+// contribute to quality and accuracy thanks to anti-aliasing.
+QPainterPath SaSpectrumView::makePath(std::vector<float> &displayBuffer, float resolution = 1.0)
+{
+	// convert resolution to number of path points per logical pixel
+	float pixel_limit = resolution * window()->devicePixelRatio();
+
+	QPainterPath path;
+	path.moveTo(m_displayLeft, m_displayBottom);
+
+	// Translate frequency bins to path points.
+	// Display is flipped: y values grow towards zero, initial max is bottom.
+	// Bins falling to interval [x_start, x_next) contribute to a single point.
+	float max = m_displayBottom;
+	float x_start = -1;		// lower bound of currently constructed point
+	for (unsigned int n = 0; n < m_processor->binCount(); n++)
+	{
+		float x = freqToXPixel(binToFreq(n), m_displayWidth);
+		float x_next = freqToXPixel(binToFreq(n + 1), m_displayWidth);
+		float y = ampToYPixel(displayBuffer[n], m_displayBottom);
+
+		// consider making a point only if x falls within display bounds
+		if (0 < x && x < m_displayWidth)
+		{
+			if (x_start == -1)
+			{
+				x_start = x;
+				// the first displayed bin is stretched to the left edge to prevent
+				// creating a misleading slope leading to zero (at log. scale)
+				path.lineTo(m_displayLeft, y + m_displayTop);
+			}
+			// Opt.: QPainter is very slow -- draw at most [pixel_limit] points
+			// per logical pixel. As opposed to limiting the bin count, this
+			// allows high resolution display if user resizes the analyzer.
+			// Look at bins that share the pixel and use the highest value:
+			max = y < max ? y : max;
+			// And make the final point in the middle of current interval.
+			if ((int)(x * pixel_limit) != (int)(x_next * pixel_limit))
+			{
+				x = (x + x_start) / 2;
+				path.lineTo(x + m_displayLeft, max + m_displayTop);
+				max = m_displayBottom;
+				x_start = x_next;
+			}
+		}
+		else
+		{
+			// stop processing after a bin falls outside right edge
+			// and align it to the edge to prevent a gap
+			if (n > 0 && x > 0)
+			{
+				path.lineTo(m_displayRight,	y + m_displayTop);
+				break;
+			}
+		}
+	}
+	path.lineTo(m_displayRight, m_displayBottom);
+	path.closeSubpath();
+	return path;
+}
+
+
+// Draw background, grid and associated frequency and amplitude labels.
+void SaSpectrumView::drawGrid(QPainter &painter)
+{
+	std::vector<std::pair<int, std::string>> *freqTics = NULL;
+	std::vector<std::pair<float, std::string>> *ampTics = NULL;
+	float pos = 0;
+	float label_width = 24;
+	float label_height = 15;
+	float margin = 5;
+
+	// always draw the background
+	painter.fillRect(m_displayLeft, m_displayTop,
+					 m_displayWidth, m_displayBottom,
+					 m_controls->m_colorBG);
+
+	// select logarithmic or linear frequency grid and draw it
+	if (m_controls->m_logXModel.value())
+	{
+		freqTics = &m_logFreqTics;
+	}
+	else
+	{
+		freqTics = &m_linearFreqTics;
+	}
+	// draw frequency grid (line.first is display position)
+	painter.setPen(QPen(m_controls->m_colorGrid, 1,	Qt::SolidLine, Qt::RoundCap, Qt::BevelJoin));
+	for (auto &line: *freqTics)
+	{
+		painter.drawLine(m_displayLeft + freqToXPixel(line.first, m_displayWidth),
+						 2,
+						 m_displayLeft + freqToXPixel(line.first, m_displayWidth),
+						 m_displayBottom);
+	}
+	// print frequency labels (line.second is label)
+	painter.setPen(QPen(m_controls->m_colorLabels, 1, Qt::SolidLine, Qt::RoundCap, Qt::BevelJoin));
+	for (auto & line: *freqTics)
+	{
+		pos = m_displayLeft + freqToXPixel(line.first, m_displayWidth);
+		// align first and last label to the edge if needed, otherwise center them
+		if (line == freqTics->front() && pos - label_width / 2 < m_displayLeft)
+		{
+			painter.drawText(m_displayLeft, m_displayBottom + margin,
+							 label_width, label_height, Qt::AlignLeft | Qt::TextDontClip,
+							 QString(line.second.c_str()));
+		}
+		else if (line == freqTics->back() && pos + label_width / 2 > m_displayRight)
+		{
+			painter.drawText(m_displayRight - label_width, m_displayBottom + margin,
+							 label_width, label_height, Qt::AlignRight | Qt::TextDontClip,
+							 QString(line.second.c_str()));
+		}
+		else
+		{
+			painter.drawText(pos - label_width / 2, m_displayBottom + margin,
+							 label_width, label_height, Qt::AlignHCenter | Qt::TextDontClip,
+							 QString(line.second.c_str()));
+		}
+	}
+
+	margin = 2;
+	// select logarithmic or linear amplitude grid and draw it
+	if (m_controls->m_logYModel.value())
+	{
+		ampTics = &m_logAmpTics;
+	}
+	else
+	{
+		ampTics = &m_linearAmpTics;
+	}
+	// draw amplitude grid
+	painter.setPen(QPen(m_controls->m_colorGrid, 1, Qt::SolidLine, Qt::RoundCap, Qt::BevelJoin));
+	for (auto & line: *ampTics)
+	{
+		painter.drawLine(m_displayLeft + 1,
+						 ampToYPixel(line.first, m_displayBottom),
+						 m_displayRight - 1,
+						 ampToYPixel(line.first, m_displayBottom));
+	}
+	// print amplitude labels
+	painter.setPen(QPen(m_controls->m_colorLabels, 1, Qt::SolidLine, Qt::RoundCap, Qt::BevelJoin));
+	bool stereo = m_controls->m_stereoModel.value();
+	for (auto & line: *ampTics)
+	{
+		pos = ampToYPixel(line.first, m_displayBottom);
+		// align first and last labels to edge if needed, otherwise center them
+		if (line == ampTics->back() && pos < 8)
+		{
+			if (stereo)
+			{
+				painter.setPen(QPen(m_controls->m_colorL.lighter(), 1, Qt::SolidLine, Qt::RoundCap, Qt::BevelJoin));
+			}
+			painter.drawText(m_displayLeft - label_width - margin, m_displayTop - 2,
+							 label_width, label_height, Qt::AlignRight | Qt::AlignTop | Qt::TextDontClip,
+							 QString(line.second.c_str()));
+			if (stereo)
+			{
+				painter.setPen(QPen(m_controls->m_colorR.lighter(), 1, Qt::SolidLine, Qt::RoundCap, Qt::BevelJoin));
+			}
+			painter.drawText(m_displayRight + margin, m_displayTop - 2,
+							 label_width, label_height, Qt::AlignLeft | Qt::AlignTop | Qt::TextDontClip,
+							 QString(line.second.c_str()));
+		}
+		else if (line == ampTics->front() && pos > m_displayBottom - label_height)
+		{
+			if (stereo)
+			{
+				painter.setPen(QPen(m_controls->m_colorL.lighter(), 1, Qt::SolidLine, Qt::RoundCap, Qt::BevelJoin));
+			}
+			painter.drawText(m_displayLeft - label_width - margin, m_displayBottom - label_height + 2,
+							 label_width, label_height, Qt::AlignRight | Qt::AlignBottom | Qt::TextDontClip,
+							 QString(line.second.c_str()));
+			if (stereo)
+			{
+				painter.setPen(QPen(m_controls->m_colorR.lighter(), 1, Qt::SolidLine, Qt::RoundCap, Qt::BevelJoin));
+			}
+			painter.drawText(m_displayRight + margin, m_displayBottom - label_height + 2,
+							 label_width, label_height, Qt::AlignLeft | Qt::AlignBottom | Qt::TextDontClip,
+							 QString(line.second.c_str()));
+		}
+		else
+		{
+			if (stereo)
+			{
+				painter.setPen(QPen(m_controls->m_colorL.lighter(), 1, Qt::SolidLine, Qt::RoundCap, Qt::BevelJoin));
+			}
+			painter.drawText(m_displayLeft - label_width - margin, pos - label_height / 2,
+							 label_width, label_height, Qt::AlignRight | Qt::AlignVCenter | Qt::TextDontClip,
+							 QString(line.second.c_str()));
+			if (stereo)
+			{
+				painter.setPen(QPen(m_controls->m_colorR.lighter(), 1, Qt::SolidLine, Qt::RoundCap, Qt::BevelJoin));
+			}
+			painter.drawText(m_displayRight + margin, pos - label_height / 2,
+							 label_width, label_height, Qt::AlignLeft | Qt::AlignVCenter | Qt::TextDontClip,
+							 QString(line.second.c_str()));
+		}
+	}
+}
+
+
+// Draw cursor and its coordinates if it is within display bounds.
+void SaSpectrumView::drawCursor(QPainter &painter)
+{
+	if(		m_cursor.x() >= m_displayLeft
+		&&	m_cursor.x() <= m_displayRight
+		&&	m_cursor.y() >= m_displayTop
+		&&	m_cursor.y() <= m_displayBottom)
+	{
+		// cursor lines
+		painter.setPen(QPen(m_controls->m_colorGrid.lighter(), 1, Qt::SolidLine, Qt::RoundCap, Qt::BevelJoin));
+		painter.drawLine(m_cursor.x(), m_displayTop, m_cursor.x(), m_displayBottom);
+		painter.drawLine(m_displayLeft, m_cursor.y(), m_displayRight, m_cursor.y());
+
+		// coordinates
+		painter.setPen(QPen(m_controls->m_colorLabels.darker(), 1, Qt::SolidLine, Qt::RoundCap, Qt::BevelJoin));
+		painter.drawText(m_displayRight -60, 5, 100, 16, Qt::AlignLeft, "Cursor");
+
+		QString tmps;
+		// frequency
+		int xFreq = (int)m_processor->xPixelToFreq(m_cursor.x() - m_displayLeft, m_displayWidth);
+		tmps = QString(std::string(std::to_string(xFreq) + " Hz").c_str());
+		painter.drawText(m_displayRight -60, 18, 100, 16, Qt::AlignLeft, tmps);
+
+		// amplitude
+		float yAmp = m_processor->yPixelToAmp(m_cursor.y(), m_displayBottom);
+		if (m_controls->m_logYModel.value())
+		{
+			tmps = QString(std::string(std::to_string(yAmp).substr(0, 5) + " dB").c_str());
+		}
+		else
+		{
+			// add 0.0005 to get proper rounding to 3 decimal places
+			tmps = QString(std::string(std::to_string(0.0005f + yAmp)).substr(0, 5).c_str());
+		}
+		painter.drawText(m_displayRight -60, 30, 100, 16, Qt::AlignLeft, tmps);
+	}
+}
+
+
+// Wrappers for most used SaProcessor helpers (to make local code more compact).
+float SaSpectrumView::binToFreq(unsigned int bin_index)
+{
+	return m_processor->binToFreq(bin_index);
+}
+
+
+float SaSpectrumView::freqToXPixel(float frequency, unsigned int width)
+{
+	return m_processor->freqToXPixel(frequency, width);
+}
+
+
+float SaSpectrumView::ampToYPixel(float amplitude, unsigned int height)
+{
+	return m_processor->ampToYPixel(amplitude, height);
+}
+
+
+// Generate labels suitable for logarithmic frequency scale.
+// Low / high limits are in Hz. Lowest possible label is 10 Hz.
+std::vector<std::pair<int, std::string>> SaSpectrumView::makeLogFreqTics(int low, int high)
+{
+	std::vector<std::pair<int, std::string>> result;
+	int i, j;
+	int a[] = {10, 20, 50};		// sparse series multipliers
+	int b[] = {14, 30, 70};		// additional (denser) series
+
+	// generate main steps (powers of 10); use the series to specify smaller steps
+	for (i = 1; i <= high; i *= 10)
+	{
+		for (j = 0; j < 3; j++)
+		{
+			// insert a label from sparse series if it falls within bounds
+			if (i * a[j] >= low && i * a[j] <= high)
+			{
+				if (i * a[j] < 1000)
+				{
+					result.emplace_back(i * a[j], std::to_string(i * a[j]));
+				}
+				else
+				{
+					result.emplace_back(i * a[j], std::to_string(i * a[j] / 1000) + "k");
+				}
+			}
+			// also insert denser series if high and low values are close
+			if ((log10(high) - log10(low) < 2) && (i * b[j] >= low && i * b[j] <= high))
+			{
+				if (i * b[j] < 1500)
+				{
+					result.emplace_back(i * b[j], std::to_string(i * b[j]));
+				}
+				else
+				{
+					result.emplace_back(i * b[j], std::to_string(i * b[j] / 1000) + "k");
+				}
+			}
+		}
+	}
+	return result;
+}
+
+
+// Generate labels suitable for linear frequency scale.
+// Low / high limits are in Hz.
+std::vector<std::pair<int, std::string>> SaSpectrumView::makeLinearFreqTics(int low, int high)
+{
+	std::vector<std::pair<int, std::string>> result;
+	int i, increment;
+
+	// select a suitable increment based on zoom level
+	if (high - low < 500) {increment = 50;}
+	else if (high - low < 1000) {increment = 100;}
+	else if (high - low < 5000) {increment = 1000;}
+	else {increment = 2000;}
+
+	// generate steps based on increment, starting at 0
+	for (i = 0; i <= high; i += increment)
+	{
+		if (i >= low)
+		{
+			if (i < 1000)
+			{
+				result.emplace_back(i, std::to_string(i));
+			}
+			else
+			{
+				result.emplace_back(i, std::to_string(i/1000) + "k");
+			}
+		}
+	}
+	return result;
+}
+
+
+// Generate labels suitable for logarithmic (dB) amplitude scale.
+// Low / high limits are in dB; 0 dB amplitude = 1.0 linear.
+// Treating results as power ratio, i.e., 3 dB should be about twice as loud.
+std::vector<std::pair<float, std::string>> SaSpectrumView::makeLogAmpTics(int low, int high)
+{
+	std::vector<std::pair<float, std::string>> result;
+	float i;
+	double increment;
+
+	// Base zoom level on selected range and how close is the current height
+	// to the sizeHint() (denser scale for bigger window).
+	if ((high - low) < 20 * ((float)height() / sizeHint().height()))
+	{
+		increment = pow(10, 0.3);	// 3 dB steps when really zoomed in
+	}
+	else if (high - low < 45 * ((float)height() / sizeHint().height()))
+	{
+		increment = pow(10, 0.6);	// 6 dB steps when sufficiently zoomed in
+	}
+	else
+	{
+		increment = 10;				// 10 dB steps otherwise
+	}
+
+	// Generate n dB increments, start checking at -90 dB. Limits are tweaked
+	// just a little bit to make sure float comparisons do not miss edges.
+	for (i = 0.000000001; 10 * log10(i) <= (high + 0.001); i *= increment)
+	{
+		if (10 * log10(i) >= (low - 0.001))
+		{
+			result.emplace_back(i, std::to_string((int)std::round(10 * log10(i))));
+		}
+	}
+	return result;
+}
+
+
+// Generate labels suitable for linear amplitude scale.
+// Low / high limits are in dB; 0 dB amplitude = 1.0 linear.
+// Smallest possible label is 0.001, largest is 999. This includes the majority
+// of useful labels; going lower or higher would require increasing margin size
+// so that the text can fit. That would be a waste of space -- the linear scale
+// would only make the experience worse for the main, logarithmic (dB) scale.
+std::vector<std::pair<float, std::string>> SaSpectrumView::makeLinearAmpTics(int low, int high)
+{
+	std::vector<std::pair<float, std::string>> result;
+	double i, nearest;
+
+	// make about 5 labels when window is small, 10 if it is big
+	float split = (float)height() / sizeHint().height() >= 1.5 ? 10.0 : 5.0;
+
+	// convert limits to linear scale
+	float lin_low = pow(10, low / 10.0);
+	float lin_high = pow(10, high / 10.0);
+
+	// Linear scale will vary widely, so instead of trying to craft extra nice
+	// multiples, just generate a few evenly spaced increments across the range,
+	// paying attention only to the decimal places to keep labels short.
+	// Limits are shifted a bit so that float comparisons do not miss edges.
+	for (i = 0; i <= (lin_high + 0.0001); i += (lin_high - lin_low) / split)
+	{
+		if (i >= (lin_low - 0.0001))
+		{
+			if (i >= 9.99 && i < 99.9)
+			{
+				nearest = std::round(i);
+				result.emplace_back(nearest, std::to_string(nearest).substr(0, 2));
+			}
+			else if (i >= 0.099)
+			{	// also covers numbers above 100
+				nearest = std::round(i * 10) / 10;
+				result.emplace_back(nearest, std::to_string(nearest).substr(0, 3));
+			}
+			else if (i >= 0.0099)
+			{
+				nearest = std::round(i * 1000) / 1000;
+				result.emplace_back(nearest, std::to_string(nearest).substr(0, 4));
+			}
+			else if	(i >= 0.00099)
+			{
+				nearest = std::round(i * 10000) / 10000;
+				result.emplace_back(nearest, std::to_string(nearest).substr(1, 4));
+			}
+			else if (i > -0.01 && i < 0.01)
+			{
+				result.emplace_back(i, "0");	// an exception, zero is short..
+			}
+		}
+	}
+	return result;
+}
+
+
+// Periodic update is called by LMMS.
+void SaSpectrumView::periodicUpdate()
+{
+	// check if the widget is visible; if it is not, processing can be paused
+	m_processor->setSpectrumActive(isVisible());
+	// tell Qt it is time for repaint
+	update();
+}
+
+
+// Handle mouse input: set new cursor position.
+void SaSpectrumView::mouseMoveEvent(QMouseEvent *event)
+{
+	m_cursor = event->pos();
+}
+
+void SaSpectrumView::mousePressEvent(QMouseEvent *event)
+{
+	m_cursor = event->pos();
+}
+
+
+// Handle resize event: rebuild grid and labels
+void SaSpectrumView::resizeEvent(QResizeEvent *event)
+{
+	// frequency does not change density with size
+	// amplitude does: rebuild labels
+	m_logAmpTics = makeLogAmpTics(m_processor->getAmpRangeMin(), m_processor->getAmpRangeMax());
+	m_linearAmpTics = makeLinearAmpTics(m_processor->getAmpRangeMin(), m_processor->getAmpRangeMax());
+}
+

plugins/SpectrumAnalyzer/SaSpectrumView.h

@@ -0,0 +1,126 @@
+/* SaSpectrumView.h - declaration of SaSpectrumView class.
+ *
+ * Copyright (c) 2019 Martin Pavelek <he29/dot/HS/at/gmail/dot/com>
+ *
+ * Based partially on Eq plugin code,
+ * Copyright (c) 2014 David French <dave/dot/french3/at/googlemail/dot/com>
+ *
+ * This file is part of LMMS - https://lmms.io
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program (see COPYING); if not, write to the
+ * Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+ * Boston, MA 02110-1301 USA.
+ *
+ */
+
+#ifndef SASPECTRUMVIEW_H
+#define SASPECTRUMVIEW_H
+
+#include <string>
+#include <utility>
+#include <QPainterPath>
+#include <QWidget>
+
+class QMouseEvent;
+class QPainter;
+class SaControls;
+class SaProcessor;
+
+//! Widget that displays a spectrum curve and frequency / amplitude grid
+class SaSpectrumView : public QWidget
+{
+	Q_OBJECT
+public:
+	explicit SaSpectrumView(SaControls *controls, SaProcessor *processor, QWidget *_parent = 0);
+	virtual ~SaSpectrumView() {}
+
+	QSize sizeHint() const override {return QSize(400, 200);}
+
+protected:
+	void paintEvent(QPaintEvent *event) override;
+	void mouseMoveEvent(QMouseEvent *event) override;
+	void mousePressEvent(QMouseEvent *event) override;
+	void resizeEvent(QResizeEvent *event) override;
+
+private slots:
+	void periodicUpdate();
+
+private:
+	const SaControls *m_controls;
+	SaProcessor *m_processor;
+
+	// grid labels (position, label) and methods to generate them
+	std::vector<std::pair<int, std::string>> m_logFreqTics;		// 10-20-50... Hz
+	std::vector<std::pair<int, std::string>> m_linearFreqTics;	// 2k-4k-6k... Hz
+	std::vector<std::pair<float, std::string>> m_logAmpTics;	// dB
+	std::vector<std::pair<float, std::string>> m_linearAmpTics;	// 0..1
+
+	std::vector<std::pair<int, std::string>> makeLogFreqTics(int low, int high);
+	std::vector<std::pair<int, std::string>> makeLinearFreqTics(int low, int high);
+	std::vector<std::pair<float, std::string>> makeLogAmpTics(int low, int high);
+	std::vector<std::pair<float, std::string>> makeLinearAmpTics(int low, int high);
+
+	// currently selected ranges (see SaControls.h for enum definitions)
+	int m_freqRangeIndex;
+	int m_ampRangeIndex;
+
+	// draw the grid and all labels based on selected ranges
+	void drawGrid(QPainter &painter);
+
+	// local buffers for frequency bin values and a method to update them
+	// (mainly needed for averaging and to keep track of peak values)
+	std::vector<float> m_displayBufferL;
+	std::vector<float> m_displayBufferR;
+	std::vector<float> m_peakBufferL;
+	std::vector<float> m_peakBufferR;
+	void updateBuffers(float *spectrum, float *displayBuffer, float *peakBuffer);
+
+	// final paths to be drawn by QPainter and methods to build them
+	QPainterPath m_pathL;
+	QPainterPath m_pathR;
+	QPainterPath m_pathPeakL;
+	QPainterPath m_pathPeakR;
+	void refreshPaths();
+	QPainterPath makePath(std::vector<float> &displayBuffer, float resolution);
+
+	// helper variables for path drawing
+	float m_decaySum;		// indicates if there is anything left to draw
+	bool m_freezeRequest;	// new reference should be acquired
+	bool m_frozen;			// a reference is currently stored in the peakBuffer
+
+	const float m_smoothFactor = 0.15;		// alpha for exponential smoothing
+	const float m_peakDecayFactor = 0.992;	// multiplier for gradual peak decay
+
+	// top level: refresh buffers, make paths and draw the spectrum
+	void drawSpectrum(QPainter &painter);
+
+	// current cursor location and a method to draw it
+	QPoint m_cursor;
+	void drawCursor(QPainter &painter);
+
+	// wrappers for most used SaProcessor conversion helpers
+	// (to make local code more readable)
+	float binToFreq(unsigned int bin_index);
+	float freqToXPixel(float frequency, unsigned int width);
+	float ampToYPixel(float amplitude, unsigned int height);
+
+	// current boundaries for drawing
+	unsigned int m_displayTop;
+	unsigned int m_displayBottom;
+	unsigned int m_displayLeft;
+	unsigned int m_displayRight;
+	unsigned int m_displayWidth;
+};
+#endif // SASPECTRUMVIEW_H
+

plugins/SpectrumAnalyzer/SaWaterfallView.cpp

@@ -0,0 +1,230 @@
+/* SaWaterfallViewView.cpp - implementation of SaWaterfallViewView class.
+ *
+ * Copyright (c) 2019 Martin Pavelek <he29/dot/HS/at/gmail/dot/com>
+ *
+ * This file is part of LMMS - https://lmms.io
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.	See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program (see COPYING); if not, write to the
+ * Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+ * Boston, MA 02110-1301 USA.
+ *
+ */
+
+#include "SaWaterfallView.h"
+
+#include <algorithm>
+#include <cmath>
+#include <QImage>
+#include <QMutexLocker>
+#include <QPainter>
+#include <QSplitter>
+#include <QString>
+
+#include "EffectControlDialog.h"
+#include "GuiApplication.h"
+#include "MainWindow.h"
+#include "SaProcessor.h"
+
+
+SaWaterfallView::SaWaterfallView(SaControls *controls, SaProcessor *processor, QWidget *_parent) :
+	QWidget(_parent),
+	m_controls(controls),
+	m_processor(processor)
+{
+	m_controlDialog = (EffectControlDialog*) _parent;
+	setMinimumSize(300, 150);
+	setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Expanding);
+
+	connect(gui->mainWindow(), SIGNAL(periodicUpdate()), this, SLOT(periodicUpdate()));
+
+	m_timeTics = makeTimeTics();
+	m_oldTimePerLine = (float)m_processor->m_inBlockSize / m_processor->getSampleRate();
+}
+
+
+// Compose and draw all the content; called by Qt.
+// Not as performance sensitive as SaSpectrumView, most of the processing is
+// done directly in SaProcessor.
+void SaWaterfallView::paintEvent(QPaintEvent *event)
+{
+	#ifdef SA_DEBUG
+		int start_time = std::chrono::high_resolution_clock::now().time_since_epoch().count();
+	#endif
+
+	// all drawing done here, local variables are sufficient for the boundary
+	const int displayTop = 1;
+	const int displayBottom = height() -2;
+	const int displayLeft = 26;
+	const int displayRight = width() -26;
+	const int displayWidth = displayRight - displayLeft;
+	float label_width = 20;
+	float label_height = 16;
+	float margin = 2;
+
+	QPainter painter(this);
+	painter.setRenderHint(QPainter::Antialiasing, true);
+
+	// check if time labels need to be rebuilt
+	if ((float)m_processor->m_inBlockSize / m_processor->getSampleRate() != m_oldTimePerLine)
+	{
+		m_timeTics = makeTimeTics();
+		m_oldTimePerLine = (float)m_processor->m_inBlockSize / m_processor->getSampleRate();
+	}
+
+	// print time labels
+	float pos = 0;
+	painter.setPen(QPen(m_controls->m_colorLabels, 1, Qt::SolidLine, Qt::RoundCap, Qt::BevelJoin));
+	for (auto & line: m_timeTics)
+	{
+		pos = timeToYPixel(line.first, displayBottom);
+		// align first and last label to the edge if needed, otherwise center them
+		if (line == m_timeTics.front() && pos < label_height / 2)
+		{
+			painter.drawText(displayLeft - label_width - margin, displayTop - 1,
+							 label_width, label_height, Qt::AlignRight | Qt::AlignTop | Qt::TextDontClip,
+							 QString(line.second.c_str()));
+			painter.drawText(displayRight + margin, displayTop - 1,
+							 label_width, label_height, Qt::AlignLeft | Qt::AlignTop | Qt::TextDontClip,
+							 QString(line.second.c_str()));
+		}
+		else if (line == m_timeTics.back() && pos > displayBottom - label_height + 2)
+		{
+			painter.drawText(displayLeft - label_width - margin, displayBottom - label_height,
+							 label_width, label_height, Qt::AlignRight | Qt::AlignBottom | Qt::TextDontClip,
+							 QString(line.second.c_str()));
+			painter.drawText(displayRight + margin, displayBottom - label_height + 2,
+							 label_width, label_height, Qt::AlignLeft | Qt::AlignBottom | Qt::TextDontClip,
+							 QString(line.second.c_str()));
+		}
+		else
+		{
+			painter.drawText(displayLeft - label_width - margin, pos - label_height / 2,
+							 label_width, label_height, Qt::AlignRight | Qt::AlignVCenter | Qt::TextDontClip,
+							 QString(line.second.c_str()));
+			painter.drawText(displayRight + margin, pos - label_height / 2,
+							 label_width, label_height, Qt::AlignLeft | Qt::AlignVCenter | Qt::TextDontClip,
+							 QString(line.second.c_str()));
+		}
+	}
+
+	// draw the spectrogram precomputed in SaProcessor
+	if (m_processor->m_waterfallNotEmpty)
+	{
+		QMutexLocker lock(&m_processor->m_dataAccess);
+		painter.drawImage(displayLeft, displayTop,					// top left corner coordinates
+						  QImage(m_processor->m_history.data(),		// raw pixel data to display
+								 m_processor->binCount(),			// width = number of frequency bins
+								 m_processor->m_waterfallHeight,	// height = number of history lines
+								 QImage::Format_RGB32
+								 ).scaled(displayWidth,				// scale to fit view..
+										  displayBottom,
+										  Qt::IgnoreAspectRatio,
+										  Qt::SmoothTransformation));
+		lock.unlock();
+	}
+	else
+	{
+		painter.fillRect(displayLeft, displayTop, displayWidth, displayBottom, QColor(0,0,0));
+	}
+
+	// always draw the outline
+	painter.setPen(QPen(m_controls->m_colorGrid, 2, Qt::SolidLine, Qt::RoundCap, Qt::BevelJoin));
+	painter.drawRoundedRect(displayLeft, displayTop, displayWidth, displayBottom, 2.0, 2.0);
+
+	#ifdef SA_DEBUG
+		// display what FPS would be achieved if waterfall ran in a loop
+		start_time = std::chrono::high_resolution_clock::now().time_since_epoch().count() - start_time;
+		painter.setPen(QPen(m_controls->m_colorLabels, 1, Qt::SolidLine, Qt::RoundCap, Qt::BevelJoin));
+		painter.drawText(displayRight -100, 10, 100, 16, Qt::AlignLeft,
+						 QString(std::string("Max FPS: " + std::to_string(1000000000.0 / start_time)).c_str()));
+	#endif
+}
+
+
+// Convert time value to Y coordinate for display of given height.
+float SaWaterfallView::timeToYPixel(float time, int height)
+{
+	float pixels_per_line = (float)height / m_processor->m_waterfallHeight;
+	float seconds_per_line = ((float)m_processor->m_inBlockSize / m_processor->getSampleRate());
+
+	return pixels_per_line * time / seconds_per_line;
+}
+
+
+// Generate labels for linear time scale.
+std::vector<std::pair<float, std::string>> SaWaterfallView::makeTimeTics()
+{
+	std::vector<std::pair<float, std::string>> result;
+	float i;
+
+	// upper limit defined by number of lines * time per line
+	float limit = m_processor->m_waterfallHeight * ((float)m_processor->m_inBlockSize / m_processor->getSampleRate());
+
+	// set increment so that about 8 tics are generated
+	float increment = std::round(10 * limit / 7) / 10;
+
+	// NOTE: labels positions are rounded to match the (rounded) label value
+	for (i = 0; i <= limit; i += increment)
+	{
+		if (i < 10)
+		{
+			result.emplace_back(std::round(i * 10) / 10, std::to_string(std::round(i * 10) / 10).substr(0, 3));
+		}
+		else
+		{
+			result.emplace_back(std::round(i), std::to_string(std::round(i)).substr(0, 2));
+		}
+	}
+	return result;
+}
+
+
+// Periodically trigger repaint and check if the widget is visible.
+// If it is not, stop drawing and inform the processor.
+void SaWaterfallView::periodicUpdate()
+{
+	m_processor->setWaterfallActive(isVisible());
+	if (isVisible()) {update();}
+}
+
+
+// Adjust window size and widget visibility when waterfall is enabled or disabbled.
+void SaWaterfallView::updateVisibility()
+{
+	// get container of the control dialog to be resized if needed
+	QWidget *subWindow = m_controlDialog->parentWidget();
+
+
+	if (m_controls->m_waterfallModel.value())
+	{
+		// clear old data before showing the waterfall
+		QMutexLocker lock(&m_processor->m_dataAccess);
+		std::fill(m_processor->m_history.begin(), m_processor->m_history.end(), 0);
+		lock.unlock();
+
+		setVisible(true);
+
+		// increase window size if it is too small
+		if (subWindow->size().height() < m_controlDialog->sizeHint().height())
+		{
+			subWindow->resize(subWindow->size().width(), m_controlDialog->sizeHint().height());
+		}
+	}
+	else
+	{
+		setVisible(false);
+		// decrease window size only if it does not violate sizeHint
+		subWindow->resize(subWindow->size().width(), m_controlDialog->sizeHint().height());
+	}
+}
+

plugins/SpectrumAnalyzer/SaWaterfallView.h

@@ -0,0 +1,66 @@
+/* SaWaterfallView.h - declaration of SaWaterfallView class.
+ *
+ * Copyright (c) 2019 Martin Pavelek <he29/dot/HS/at/gmail/dot/com>
+ *
+ * This file is part of LMMS - https://lmms.io
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program (see COPYING); if not, write to the
+ * Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+ * Boston, MA 02110-1301 USA.
+ *
+ */
+#ifndef SAWATERFALLVIEW_H
+#define SAWATERFALLVIEW_H
+
+#include <string>
+#include <utility>
+#include <vector>
+#include <QPainter>
+#include <QWidget>
+
+#include "SaControls.h"
+#include "SaProcessor.h"
+
+
+// Widget that displays a spectrum waterfall (spectrogram) and time labels.
+class SaWaterfallView : public QWidget
+{
+	Q_OBJECT
+public:
+	explicit SaWaterfallView(SaControls *controls, SaProcessor *processor, QWidget *_parent = 0);
+	virtual ~SaWaterfallView() {}
+
+	QSize sizeHint() const override {return QSize(400, 350);}
+
+	// Check if waterfall should be displayed and adjust window size if needed.
+	void updateVisibility();
+
+protected:
+	void paintEvent(QPaintEvent *event) override;
+
+private slots:
+	void periodicUpdate();
+
+private:
+	const SaControls *m_controls;
+	SaProcessor *m_processor;
+	const EffectControlDialog *m_controlDialog;
+
+	// Methods and data used to make time labels
+	float m_oldTimePerLine;
+	float timeToYPixel(float time, int height);
+	std::vector<std::pair<float, std::string>> makeTimeTics();
+	std::vector<std::pair<float, std::string>> m_timeTics;	// 0..n (s)
+};
+#endif // SAWATERFALLVIEW_H

plugins/SpectrumAnalyzer/SpectrumAnalyzer.cpp

@@ -1,172 +0,0 @@
-/*
- * SpectrumAnalyzer.cpp - spectrum analyzer effect plugin
- *
- * Copyright (c) 2008-2014 Tobias Doerffel <tobydox/at/users.sourceforge.net>
- *
- * This file is part of LMMS - https://lmms.io
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public
- * License as published by the Free Software Foundation; either
- * version 2 of the License, or (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * General Public License for more details.
- *
- * You should have received a copy of the GNU General Public
- * License along with this program (see COPYING); if not, write to the
- * Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
- * Boston, MA 02110-1301 USA.
- *
- */
-
-#include "SpectrumAnalyzer.h"
-
-#include "embed.h"
-#include "plugin_export.h"
-
-extern "C"
-{
-
-Plugin::Descriptor PLUGIN_EXPORT spectrumanalyzer_plugin_descriptor =
-{
-	STRINGIFY( PLUGIN_NAME ),
-	"Spectrum Analyzer",
-	QT_TRANSLATE_NOOP( "pluginBrowser", "Graphical spectrum analyzer plugin" ),
-	"Tobias Doerffel <tobydox/at/users.sf.net>",
-	0x0100,
-	Plugin::Effect,
-	new PluginPixmapLoader(),
-	NULL,
-	NULL
-} ;
-
-}
-
-
-
-SpectrumAnalyzer::SpectrumAnalyzer( Model * _parent,
-			const Descriptor::SubPluginFeatures::Key * _key ) :
-	Effect( &spectrumanalyzer_plugin_descriptor, _parent, _key ),
-	m_saControls( this ),
-	m_framesFilledUp( 0 ),
-	m_energy( 0 )
-{
-	memset( m_buffer, 0, sizeof( m_buffer ) );
-
-	m_specBuf = (fftwf_complex *) fftwf_malloc( ( FFT_BUFFER_SIZE + 1 ) * sizeof( fftwf_complex ) );
-	m_fftPlan = fftwf_plan_dft_r2c_1d( FFT_BUFFER_SIZE*2, m_buffer, m_specBuf, FFTW_MEASURE );
-}
-
-
-
-
-SpectrumAnalyzer::~SpectrumAnalyzer()
-{
-	fftwf_destroy_plan( m_fftPlan );
-	fftwf_free( m_specBuf );
-}
-
-
-
-
-bool SpectrumAnalyzer::processAudioBuffer( sampleFrame* _buf, const fpp_t _frames )
-{
-	if( !isEnabled() || !isRunning () )
-	{
-		return false;
-	}
-
-	if( !m_saControls.isViewVisible() )
-	{
-		return true;
-	}
-
-	fpp_t f = 0;
-	if( _frames > FFT_BUFFER_SIZE )
-	{
-		m_framesFilledUp = 0;
-		f = _frames - FFT_BUFFER_SIZE;
-	}
-
-	const int cm = m_saControls.m_channelMode.value();
-
-	switch( cm )
-	{
-		case MergeChannels:
-			for( ; f < _frames; ++f )
-			{
-				m_buffer[m_framesFilledUp] =
-					( _buf[f][0] + _buf[f][1] ) * 0.5;
-				++m_framesFilledUp;
-			}
-			break;
-		case LeftChannel:
-			for( ; f < _frames; ++f )
-			{
-				m_buffer[m_framesFilledUp] = _buf[f][0];
-				++m_framesFilledUp;
-			}
-			break;
-		case RightChannel:
-			for( ; f < _frames; ++f )
-			{
-				m_buffer[m_framesFilledUp] = _buf[f][1];
-				++m_framesFilledUp;
-			}
-			break;
-	}
-
-	if( m_framesFilledUp < FFT_BUFFER_SIZE )
-	{
-		return isRunning();
-	}
-
-
-//	hanming( m_buffer, FFT_BUFFER_SIZE, HAMMING );
-
-	const sample_rate_t sr = Engine::mixer()->processingSampleRate();
-	const int LOWEST_FREQ = 0;
-	const int HIGHEST_FREQ = sr / 2;
-
-	fftwf_execute( m_fftPlan );
-	absspec( m_specBuf, m_absSpecBuf, FFT_BUFFER_SIZE+1 );
-	if( m_saControls.m_linearSpec.value() )
-	{
-		compressbands( m_absSpecBuf, m_bands, FFT_BUFFER_SIZE+1,
-			MAX_BANDS,
-			(int)(LOWEST_FREQ*(FFT_BUFFER_SIZE+1)/(float)(sr/2)),
-			(int)(HIGHEST_FREQ*(FFT_BUFFER_SIZE+1)/(float)(sr/2)));
-		m_energy = maximum( m_bands, MAX_BANDS ) / maximum( m_buffer, FFT_BUFFER_SIZE );
-	}
-	else
-	{
-		calc13octaveband31( m_absSpecBuf, m_bands, FFT_BUFFER_SIZE+1, sr/2.0 );
-		m_energy = signalpower( m_buffer, FFT_BUFFER_SIZE ) / maximum( m_buffer, FFT_BUFFER_SIZE );
-	}
-
-
-	m_framesFilledUp = 0;
-
-	checkGate( 1 );
-
-	return isRunning();
-}
-
-
-
-
-
-extern "C"
-{
-
-// necessary for getting instance out of shared lib
-PLUGIN_EXPORT Plugin * lmms_plugin_main( Model* parent, void* data )
-{
-	return new SpectrumAnalyzer( parent, static_cast<const Plugin::Descriptor::SubPluginFeatures::Key *>( data ) );
-}
-
-}
-

plugins/SpectrumAnalyzer/SpectrumAnalyzer.h

@@ -1,78 +0,0 @@
-/*
- * SpectrumAnalyzer.h - spectrum anaylzer effect plugin
- *
- * Copyright (c) 2008-2014 Tobias Doerffel <tobydox/at/users.sourceforge.net>
- * 
- * This file is part of LMMS - https://lmms.io
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public
- * License as published by the Free Software Foundation; either
- * version 2 of the License, or (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * General Public License for more details.
- *
- * You should have received a copy of the GNU General Public
- * License along with this program (see COPYING); if not, write to the
- * Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
- * Boston, MA 02110-1301 USA.
- *
- */
-
-
-#ifndef _SPECTRUM_ANALYZER_H
-#define _SPECTRUM_ANALYZER_H
-
-#include "Effect.h"
-#include "fft_helpers.h"
-#include "SpectrumAnalyzerControls.h"
-
-
-const int MAX_BANDS = 249;
-
-
-class SpectrumAnalyzer : public Effect
-{
-public:
-	enum ChannelModes
-	{
-		MergeChannels,
-		LeftChannel,
-		RightChannel
-	} ;
-
-	SpectrumAnalyzer( Model * _parent,
-			const Descriptor::SubPluginFeatures::Key * _key );
-	virtual ~SpectrumAnalyzer();
-	virtual bool processAudioBuffer( sampleFrame * _buf,
-							const fpp_t _frames );
-
-	virtual EffectControls * controls()
-	{
-		return( &m_saControls );
-	}
-
-
-private:
-	SpectrumAnalyzerControls m_saControls;
-
-	fftwf_plan m_fftPlan;
-
-	fftwf_complex * m_specBuf;
-	float m_absSpecBuf[FFT_BUFFER_SIZE+1];
-	float m_buffer[FFT_BUFFER_SIZE*2];
-	int m_framesFilledUp;
-
-	float m_bands[MAX_BANDS];
-	float m_energy;
-
-	friend class SpectrumAnalyzerControls;
-	friend class SpectrumView;
-
-} ;
-
-
-#endif

plugins/SpectrumAnalyzer/SpectrumAnalyzerControlDialog.cpp

@@ -1,194 +0,0 @@
-/*
- * SpectrumAnalyzerControlDialog.cpp - view for spectrum analyzer
- *
- * Copyright (c) 2008-2014 Tobias Doerffel <tobydox/at/users.sourceforge.net>
- *
- * This file is part of LMMS - https://lmms.io
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public
- * License as published by the Free Software Foundation; either
- * version 2 of the License, or (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * General Public License for more details.
- *
- * You should have received a copy of the GNU General Public
- * License along with this program (see COPYING); if not, write to the
- * Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
- * Boston, MA 02110-1301 USA.
- *
- */
-
-#include <cmath>
-
-#include <QLayout>
-#include <QPainter>
-
-#include "SpectrumAnalyzer.h"
-#include "MainWindow.h"
-#include "GuiApplication.h"
-#include "LedCheckbox.h"
-#include "embed.h"
-
-
-static inline void darken( QImage& img, int x, int y, int w, int h )
-{
-	int imgWidth = img.width();
-	QRgb * base = ( (QRgb *) img.bits() ) + y*imgWidth + x;
-	for( int y = 0; y < h; ++y )
-	{
-		QRgb * d = base + y*imgWidth;
-		for( int x = 0; x < w; ++x )
-		{
-			// shift each color component by 1 bit and set alpha
-			// to 0xff
-			d[x] = ( ( d[x] >> 1 ) & 0x7f7f7f7f ) | 0xff000000;
-		}
-	}
-}
-
-
-
-class SpectrumView : public QWidget
-{
-public:
-	SpectrumView( SpectrumAnalyzer* s, QWidget * _parent ) :
-		QWidget( _parent ),
-		m_sa( s ),
-		m_backgroundPlain( PLUGIN_NAME::getIconPixmap( "spectrum_background_plain" ).toImage() ),
-		m_background( PLUGIN_NAME::getIconPixmap( "spectrum_background" ).toImage() )
-	{
-		setFixedSize( 249, 151 );
-		connect( gui->mainWindow(), SIGNAL( periodicUpdate() ), this, SLOT( update() ) );
-		setAttribute( Qt::WA_OpaquePaintEvent, true );
-	}
-
-	virtual ~SpectrumView()
-	{
-	}
-
-	virtual void paintEvent( QPaintEvent* event )
-	{
-		QPainter p( this );
-		QImage i = m_sa->m_saControls.m_linearSpec.value() ?
-					m_backgroundPlain : m_background;
-		const float e = m_sa->m_energy;
-		if( e <= 0 )
-		{
-			darken( i, 0, 0, i.width(), i.height() );
-			p.drawImage( 0, 0, i );
-			return;
-		}
-
-		const bool lin_y = m_sa->m_saControls.m_linearYAxis.value();
-		float * b = m_sa->m_bands;
-		const int LOWER_Y = -60;	// dB
-		int h;
-		const int fh = height();
-		if( m_sa->m_saControls.m_linearSpec.value() )
-		{
-			if( lin_y )
-			{
-				for( int x = 0; x < MAX_BANDS; ++x, ++b )
-				{
-					h = fh * 2.0 / 3.0 * (*b / e );
-					if( h < 0 ) h = 0; else if( h >= fh ) continue;
-					darken( i, x, 0, 1, fh-h );
-				}
-			}
-			else
-			{
-				for( int x = 0; x < MAX_BANDS; ++x, ++b )
-				{
-					h = (int)( fh * 2.0 / 3.0 * (20*(log10( *b / e ) ) - LOWER_Y ) / (-LOWER_Y ) );
-					if( h < 0 ) h = 0; else if( h >= fh ) continue;
-					darken( i, x, 0, 1, fh-h );
-				}
-			}
-		}
-		else
-		{
-			if( lin_y )
-			{
-				for( int x = 0; x < 31; ++x, ++b )
-				{
-					h = fh * 2.0 / 3.0 * ( 1.2 * *b / e );
-					if( h < 0 ) h = 0; else if( h >= fh ) continue; else h = ( h / 3 ) * 3;
-					darken( i, x*8, 0, 8, fh-h );
-				}
-			}
-			else
-			{
-				for( int x = 0; x < 31; ++x, ++b )
-				{
-					h = (int)( fh * 2.0 / 3.0 * (20*(log10( *b / e ) ) - LOWER_Y ) / (-LOWER_Y ) );
-					if( h < 0 ) h = 0; else if( h >= fh ) continue; else h = ( h / 3 ) * 3;
-					darken( i, x*8, 0, 8, fh-h );
-				}
-			}
-			darken( i, 31*8, 0, 1, fh );
-		}
-		p.drawImage( 0, 0, i );
-	}
-
-
-private:
-	SpectrumAnalyzer * m_sa;
-	QImage m_backgroundPlain;
-	QImage m_background;
-
-} ;
-
-
-
-
-SpectrumAnalyzerControlDialog::SpectrumAnalyzerControlDialog( SpectrumAnalyzerControls* controls ) :
-	EffectControlDialog( controls ),
-	m_controls( controls ),
-	m_logXAxis( PLUGIN_NAME::getIconPixmap( "log_x_axis" ) ),
-	m_logYAxis( PLUGIN_NAME::getIconPixmap( "log_y_axis" ) )
-{
-	setAutoFillBackground( true );
-	QPalette pal;
-	pal.setBrush( backgroundRole(), PLUGIN_NAME::getIconPixmap( "background" ) );
-	setFixedSize( 293, 205 );
-	setPalette( pal );
-/*	QVBoxLayout * l = new QVBoxLayout( this );*/
-	SpectrumView* v = new SpectrumView( controls->m_effect, this );
-	v->move( 34, 10 );
-
-	LedCheckBox * lin_spec = new LedCheckBox( tr( "Linear spectrum" ), this );
-	lin_spec->move( 32, 182 );
-	lin_spec->setModel( &controls->m_linearSpec );
-
-	LedCheckBox * lin_y = new LedCheckBox( tr( "Linear Y axis" ), this );
-	lin_y->move( 137, 182 );
-	lin_y->setModel( &controls->m_linearYAxis );
-
-	connect( &controls->m_linearSpec, SIGNAL( dataChanged() ), this, SLOT( update() ) );
-	connect( &controls->m_linearYAxis, SIGNAL( dataChanged() ), this, SLOT( update() ) );
-/*	l->addWidget( v );
-	l->addWidget( lin_spec );
-	l->addWidget( lin_y );*/
-
-}
-
-
-void SpectrumAnalyzerControlDialog::paintEvent( QPaintEvent * )
-{
-	QPainter p( this );
-
-	if( !m_controls->m_linearSpec.value() )
-	{
-		p.drawPixmap( 33, 165, m_logXAxis );
-	}
-
-	if( !m_controls->m_linearYAxis.value() )
-	{
-		p.drawPixmap( 10, 29, m_logYAxis);
-	}
-
-}

plugins/SpectrumAnalyzer/SpectrumAnalyzerControls.cpp

@@ -1,61 +0,0 @@
-/*
- * SpectrumAnalyzerControls.cpp - controls for spectrum analyzer
- *
- * Copyright (c) 2008-2014 Tobias Doerffel <tobydox/at/users.sourceforge.net>
- * 
- * This file is part of LMMS - https://lmms.io
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public
- * License as published by the Free Software Foundation; either
- * version 2 of the License, or (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * General Public License for more details.
- *
- * You should have received a copy of the GNU General Public
- * License along with this program (see COPYING); if not, write to the
- * Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
- * Boston, MA 02110-1301 USA.
- *
- */
-
-
-#include "SpectrumAnalyzer.h"
-#include "SpectrumAnalyzerControls.h"
-
-
-
-SpectrumAnalyzerControls::SpectrumAnalyzerControls( SpectrumAnalyzer* effect ) :
-	EffectControls( effect ),
-	m_effect( effect ),
-	m_linearSpec( false, this, tr( "Linear spectrum" ) ),
-	m_linearYAxis( false, this, tr( "Linear Y axis" ) ),
-	m_channelMode( SpectrumAnalyzer::MergeChannels,
-					SpectrumAnalyzer::MergeChannels,
-					SpectrumAnalyzer::RightChannel,
-						this, tr( "Channel mode" ) )
-{
-}
-
-
-
-
-void SpectrumAnalyzerControls::loadSettings( const QDomElement & _this )
-{
-}
-
-
-
-
-void SpectrumAnalyzerControls::saveSettings( QDomDocument & _doc, 
-							QDomElement & _this )
-{
-}
-
-
-
-
-

plugins/SpectrumAnalyzer/SpectrumAnalyzerControls.h

@@ -1,75 +0,0 @@
-/*
- * SpectrumAnalyzerControls.h - controls for spectrum-analyzer
- *
- * Copyright (c) 2008-2014 Tobias Doerffel <tobydox/at/users.sourceforge.net>
- * 
- * This file is part of LMMS - https://lmms.io
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public
- * License as published by the Free Software Foundation; either
- * version 2 of the License, or (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * General Public License for more details.
- *
- * You should have received a copy of the GNU General Public
- * License along with this program (see COPYING); if not, write to the
- * Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
- * Boston, MA 02110-1301 USA.
- *
- */
-
-#ifndef SPECTRUM_ANALYZER_CONTROLS_H
-#define SPECTRUM_ANALYZER_CONTROLS_H
-
-#include "EffectControls.h"
-#include "SpectrumAnalyzerControlDialog.h"
-#include "Knob.h"
-
-
-class SpectrumAnalyzer;
-
-
-class SpectrumAnalyzerControls : public EffectControls
-{
-	Q_OBJECT
-public:
-	SpectrumAnalyzerControls( SpectrumAnalyzer* effect );
-	virtual ~SpectrumAnalyzerControls()
-	{
-	}
-
-	virtual void saveSettings( QDomDocument & _doc, QDomElement & _parent );
-	virtual void loadSettings( const QDomElement & _this );
-	inline virtual QString nodeName() const
-	{
-		return "spectrumanaylzercontrols";
-	}
-
-	virtual int controlCount()
-	{
-		return 1;
-	}
-
-	virtual EffectControlDialog * createView()
-	{
-		return new SpectrumAnalyzerControlDialog( this );
-	}
-
-
-private:
-	SpectrumAnalyzer* m_effect;
-	BoolModel m_linearSpec;
-	BoolModel m_linearYAxis;
-	IntModel m_channelMode;
-
-	friend class SpectrumAnalyzer;
-	friend class SpectrumAnalyzerControlDialog;
-	friend class SpectrumView;
-
-} ;
-
-#endif

plugins/SpectrumAnalyzer/block_size.svg

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plugins/SpectrumAnalyzer/freeze.svg

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src/core/fft_helpers.cpp

@@ -2,6 +2,7 @@
  * fft_helpers.cpp - some functions around FFT analysis
  *
  * Copyright (c) 2008-2012 Tobias Doerffel <tobydox/at/users.sourceforge.net>
+ * Copyright (c) 2019 Martin Pavelek <he29.HS/at/gmail.com>
  *
  * This file is part of LMMS - https://lmms.io
  *
@@ -28,127 +29,194 @@
 #include <cmath>
 #include "lmms_constants.h"
 
-/* returns biggest value from abs_spectrum[spec_size] array
-
-   returns -1 on error
-*/
-float maximum(float *abs_spectrum, unsigned int spec_size)
+/* Returns biggest value from abs_spectrum[spec_size] array.
+ *
+ * return -1 on error, otherwise the maximum value
+ */
+float maximum(const float *abs_spectrum, unsigned int spec_size)
 {
-	float maxi=0;
+	float maxi = 0;
 	unsigned int i;
 
-	if ( abs_spectrum==NULL )
-		return -1;
+	if (abs_spectrum == NULL) {return -1;}
+	if (spec_size <= 0) {return -1;}
 
-	if (spec_size<=0)
-		return -1;
-
-	for ( i=0; i<spec_size; i++ )
+	for (i = 0; i < spec_size; i++)
 	{
-		if ( abs_spectrum[i]>maxi )
-			maxi=abs_spectrum[i];
+		if (abs_spectrum[i] > maxi) {maxi = abs_spectrum[i];}
 	}
-
 	return maxi;
 }
 
+float maximum(const std::vector<float> &abs_spectrum)
+{
+	return maximum(abs_spectrum.data(), abs_spectrum.size());
+}
 
-/* apply hanning or hamming window to channel
 
-	returns -1 on error */
-int hanming(float *timebuffer, int length, WINDOWS type)
+/* Normalize the array of absolute magnitudes to a 0..1 range.
+ * Block size refers to FFT block size before any zero padding.
+ *
+ * return -1 on error, 0 on success
+ */
+int normalize(const float *abs_spectrum, float *norm_spectrum, unsigned int bin_count, unsigned int block_size)
 {
 	int i;
-	float alpha;
 
-	if ( (timebuffer==NULL)||(length<=0) )
-		return -1;
+	if (abs_spectrum == NULL || norm_spectrum == NULL) {return -1;}
+	if (bin_count == 0 || block_size == 0) {return -1;}
 
+	for (i = 0; i < bin_count; i++)
+	{
+		norm_spectrum[i] = abs_spectrum[i] / block_size;
+	}
+	return 0;
+}
+
+int normalize(const std::vector<float> &abs_spectrum, std::vector<float> &norm_spectrum, unsigned int block_size)
+{
+	if (abs_spectrum.size() != norm_spectrum.size()) {return -1;}
+
+	return normalize(abs_spectrum.data(), norm_spectrum.data(), abs_spectrum.size(), block_size);
+}
+
+
+/* Check if the spectrum contains any non-zero value.
+ *
+ * return 1 if spectrum contains any non-zero value
+ * return 0 otherwise
+ */
+int notEmpty(const std::vector<float> &spectrum)
+{
+	for (int i = 0; i < spectrum.size(); i++)
+	{
+		if (spectrum[i] != 0) {return 1;}
+	}
+	return 0;
+}
+
+
+/* Precompute an FFT window function for later real-time use.
+ *
+ * return -1 on error
+ */
+int precomputeWindow(float *window, unsigned int length, FFT_WINDOWS type, bool normalized)
+{
+	unsigned int i;
+	float gain = 0;
+	float a0;
+	float a1;
+	float a2;
+	float a3;
+
+	if (window == NULL) {return -1;}
+
+	// constants taken from
+	// https://en.wikipedia.org/wiki/Window_function#AList_of_window_functions
 	switch (type)
 	{
-		case HAMMING: alpha=0.54; break;
+		default:
+		case RECTANGULAR:
+			for (i = 0; i < length; i++) {window[i] = 1.0;}
+			gain = 1;
+			return 0;
+		case BLACKMAN_HARRIS:	
+			a0 = 0.35875;
+			a1 = 0.48829;
+			a2 = 0.14128;
+			a3 = 0.01168;
+			break;
+		case HAMMING:
+			a0 = 0.54;
+			a1 = 1.0 - a0;
+			a2 = 0;
+			a3 = 0;
+			break;
 		case HANNING:
-		default: alpha=0.5; break;
+			a0 = 0.5;
+			a1 = 1.0 - a0;
+			a2 = 0;
+			a3 = 0;
+			break;
 	}
 
-	for ( i=0; i<length; i++ )
+	// common computation for cosine-sum based windows
+	for (i = 0; i < length; i++)
 	{
-		timebuffer[i]=timebuffer[i]*(alpha+(1-alpha)*cos(2*F_PI*i/((float)length-1.0)));
+		window[i] =	(a0 - a1 * cos(2 * F_PI * i / ((float)length - 1.0))
+						+ a2 * cos(4 * F_PI * i / ((float)length - 1.0))
+						- a3 * cos(6 * F_PI * i / ((float)length - 1.0)));
+		gain += window[i];
 	}
 
+	// apply amplitude correction
+	gain /= (float) length;
+	for (i = 0; i < length; i++) {window[i] /= gain;}
+
 	return 0;
 }
 
 
-/* compute absolute values of complex_buffer, save to absspec_buffer
-   take care that - compl_len is not bigger than complex_buffer!
-                  - absspec buffer is big enough!
-
-      returns 0 on success, else -1          */
-int absspec(fftwf_complex *complex_buffer, float *absspec_buffer, int compl_length)
+/* Compute absolute values of complex_buffer, save to absspec_buffer.
+ * Take care that - compl_len is not bigger than complex_buffer!
+ *                - absspec buffer is big enough!
+ *
+ * return 0 on success, else -1
+ */
+int absspec(const fftwf_complex *complex_buffer, float *absspec_buffer, unsigned int compl_length)
 {
 	int i;
 
-	if ( (complex_buffer==NULL)||(absspec_buffer==NULL) )
-		return -1;
-	if ( compl_length<=0 )
-		return -1;
+	if (complex_buffer == NULL || absspec_buffer == NULL) {return -1;}
+	if (compl_length <= 0) {return -1;}
 
-	for (i=0; i<compl_length; i++)
+	for (i = 0; i < compl_length; i++)
 	{
-		absspec_buffer[i]=(float )sqrt(complex_buffer[i][0]*complex_buffer[i][0] + complex_buffer[i][1]*complex_buffer[i][1]);
+		absspec_buffer[i] = (float)sqrt(complex_buffer[i][0] * complex_buffer[i][0]
+							+ complex_buffer[i][1] * complex_buffer[i][1]);
 	}
 
 	return 0;
 }
 
 
-/* build fewer subbands from many absolute spectrum values
-   take care that - compressedbands[] array num_new elements long
-                  - num_old > num_new
-
-     returns 0 on success, else -1          */
-int compressbands(float *absspec_buffer, float *compressedband, int num_old, int num_new, int bottom, int top)
+/* Build fewer subbands from many absolute spectrum values.
+ * Take care that - compressedbands[] array num_new elements long
+ *                - num_old > num_new
+ *
+ * return 0 on success, else -1
+ */
+int compressbands(const float *absspec_buffer, float *compressedband, int num_old, int num_new, int bottom, int top)
 {
 	float ratio;
 	int i, usefromold;
 	float j;
 	float j_min, j_max;
 
-	if ( (absspec_buffer==NULL)||(compressedband==NULL) )
-		return -1;
+	if (absspec_buffer == NULL || compressedband == NULL) {return -1;}
+	if (num_old < num_new) {return -1;}
+	if (num_old <= 0 || num_new <= 0) {return -1;}
+	if (bottom < 0) {bottom = 0;}
+	if (top >= num_old) {top = num_old - 1;}
 
-	if ( num_old<num_new )
-		return -1;
+	usefromold = num_old - (num_old - top) - bottom;
 
-	if ( (num_old<=0)||(num_new<=0) )
-		return -1;
-
-	if ( bottom<0 )
-		bottom=0;
-
-	if ( top>=num_old )
-		top=num_old-1;
-
-	usefromold=num_old-(num_old-top)-bottom;
-
-	ratio=(float)usefromold/(float)num_new;
+	ratio = (float)usefromold / (float)num_new;
 
 	// for each new subband
-	for ( i=0; i<num_new; i++ )
+	for (i = 0; i < num_new; i++)
 	{
-		compressedband[i]=0;
+		compressedband[i] = 0;
 
-		j_min=(i*ratio)+bottom;
+		j_min = (i * ratio) + bottom;
 
-		if ( j_min<0 )
-			j_min=bottom;
+		if (j_min < 0) {j_min = bottom;}
 
-		j_max=j_min+ratio;
+		j_max = j_min + ratio;
 
-		for ( j=(int)j_min; j<=j_max; j++ )
+		for (j = (int)j_min; j <= j_max; j++)
 		{
-			compressedband[i]+=absspec_buffer[(int)j];
+			compressedband[i] += absspec_buffer[(int)j];
 		}
 	}
 
@@ -158,84 +226,73 @@ int compressbands(float *absspec_buffer, float *compressedband, int num_old, int
 
 int calc13octaveband31(float *absspec_buffer, float *subbands, int num_spec, float max_frequency)
 {
-static const int onethirdoctavecenterfr[] = {20, 25, 31, 40, 50, 63, 80, 100, 125, 160, 200, 250, 315, 400, 500, 630, 800, 1000, 1250, 1600, 2000, 2500, 3150, 4000, 5000, 6300, 8000, 10000, 12500, 16000, 20000};
+	static const int onethirdoctavecenterfr[] = {20, 25, 31, 40, 50, 63, 80, 100, 125, 160, 200, 250, 315, 400, 500, 630, 800, 1000, 1250, 1600, 2000, 2500, 3150, 4000, 5000, 6300, 8000, 10000, 12500, 16000, 20000};
 	int i, j;
 	float f_min, f_max, frequency, bandwidth;
-	int j_min, j_max=0;
+	int j_min, j_max = 0;
 	float fpower;
 
-
-	if ( (absspec_buffer==NULL)||(subbands==NULL) )
-		return -1;
-
-	if ( num_spec<31 )
-		return -1;
-
-	if ( max_frequency<=0 )
-		return -1;
+	if (absspec_buffer == NULL || subbands == NULL) {return -1;}
+	if (num_spec < 31) {return -1;}
+	if (max_frequency <= 0) {return -1;}
 
 	/*** energy ***/
-	fpower=0;
-	for ( i=0; i<num_spec; i++ )
+	fpower = 0;
+	for (i = 0; i < num_spec; i++)
 	{
-		absspec_buffer[i]=(absspec_buffer[i]*absspec_buffer[i])/FFT_BUFFER_SIZE;
-		fpower=fpower+(2*absspec_buffer[i]);
+		absspec_buffer[i] = (absspec_buffer[i] * absspec_buffer[i]) / FFT_BUFFER_SIZE;
+		fpower = fpower + (2 * absspec_buffer[i]);
 	}
-	fpower=fpower-(absspec_buffer[0]); //dc not mirrored
-
+	fpower = fpower - (absspec_buffer[0]); //dc not mirrored
 
 	/*** for each subband: sum up power ***/
-	for ( i=0; i<31; i++ )
+	for (i = 0; i < 31; i++)
 	{
-		subbands[i]=0;
+		subbands[i] = 0;
 
 		// calculate bandwidth for subband
-		frequency=onethirdoctavecenterfr[i];
+		frequency = onethirdoctavecenterfr[i];
 
-		bandwidth=(pow(2, 1.0/3.0)-1)*frequency;
+		bandwidth = (pow(2, 1.0/3.0)-1) * frequency;
 
-		f_min=frequency-bandwidth/2.0;
-		f_max=frequency+bandwidth/2.0;
+		f_min = frequency - bandwidth / 2.0;
+		f_max = frequency + bandwidth / 2.0;
 
-		j_min=(int)(f_min/max_frequency*(float)num_spec);
-
-		j_max=(int)(f_max/max_frequency*(float)num_spec);
+		j_min = (int)(f_min / max_frequency * (float)num_spec);
+		j_max = (int)(f_max / max_frequency * (float)num_spec);
 
 
-		if ( (j_min<0)||(j_max<0) )
+		if (j_min < 0 || j_max < 0)
 		{
 			fprintf(stderr, "Error: calc13octaveband31() in fft_helpers.cpp line %d failed.\n", __LINE__);
 			return -1;
 		}
 
-		for ( j=j_min; j<=j_max; j++ )
+		for (j = j_min; j <= j_max; j++)
 		{
-			if( j_max<num_spec )
-				subbands[i]+=absspec_buffer[j];
+			if (j_max < num_spec) {subbands[i] += absspec_buffer[j];}
 		}
 
 	} //for
 
-
 	return 0;
 }
 
-/* compute power of finite time sequence
-   take care num_values is length of timesignal[]
-
-      returns power on success, else -1          */
-float signalpower(float *timesignal, int num_values)
+/* Compute power of finite time sequence.
+ * Take care num_values is length of timesignal[]
+ *
+ * return power on success, else -1
+ */
+float signalpower(const float *timesignal, int num_values)
 {
-	if ( num_values<=0 )
-		return -1;
+	if (num_values <= 0) {return -1;}
 
-	if( timesignal==NULL )
-		return -1;
+	if (timesignal == NULL) {return -1;}
 
-	float power=0;
-	for ( int i=0; i<num_values; i++ )
+	float power = 0;
+	for (int i = 0; i < num_values; i++)
 	{
-		power+=timesignal[i]*timesignal[i];
+		power += timesignal[i] * timesignal[i];
 	}
 
 	return power;

src/gui/MainWindow.cpp

@@ -625,6 +625,7 @@ SubWindow* MainWindow::addWindowedWidget(QWidget *w, Qt::WindowFlags windowFlags
 	SubWindow *win = new SubWindow(m_workspace->viewport(), windowFlags);
 	win->setAttribute(Qt::WA_DeleteOnClose);
 	win->setWidget(w);
+	if (w->sizeHint().isValid()) {win->resize(w->sizeHint());}
 	m_workspace->addSubWindow(win);
 	return win;
 }

src/gui/SubWindow.cpp

@@ -30,6 +30,7 @@
 
 #include <QMdiArea>
 #include <QMoveEvent>
+#include <QPainter>
 #include <QScrollBar>
 
 #include "embed.h"

src/gui/widgets/EffectView.cpp

@@ -97,9 +97,14 @@ EffectView::EffectView( Effect * _model, QWidget * _parent ) :
 		if( m_controlView )
 		{
 			m_subWindow = gui->mainWindow()->addWindowedWidget( m_controlView );
-			m_subWindow->setSizePolicy( QSizePolicy::Fixed, QSizePolicy::Fixed );
-			if (m_subWindow->layout()) {
-				m_subWindow->layout()->setSizeConstraint(QLayout::SetFixedSize);
+
+			if ( !m_controlView->isResizable() )
+			{
+				m_subWindow->setSizePolicy( QSizePolicy::Fixed, QSizePolicy::Fixed );
+				if (m_subWindow->layout())
+				{
+					m_subWindow->layout()->setSizeConstraint(QLayout::SetFixedSize);
+				}
 			}
 
 			Qt::WindowFlags flags = m_subWindow->windowFlags();

src/gui/widgets/PixmapButton.cpp

@@ -134,11 +134,11 @@ QSize PixmapButton::sizeHint() const
 {
 	if( ( model() != NULL && model()->value() ) || m_pressed )
 	{
-		return m_activePixmap.size();
+		return m_activePixmap.size() / devicePixelRatio();
 	}
 	else 
 	{
-		return m_inactivePixmap.size();
+		return m_inactivePixmap.size() / devicePixelRatio();
 	}
 }