From 9158da20e0b51ed690b5e9825ea8ddd9fe8bd036 Mon Sep 17 00:00:00 2001
From: f4exb <f4exb06@gmail.com>
Date: Wed, 17 Oct 2018 15:28:53 +0200
Subject: [PATCH] Spectrum: reviewed histogram capping to phosphor palette and
 stroke value limits

---
 sdrgui/gui/glspectrum.cpp    | 23 ++++++++++++++---------
 sdrgui/gui/glspectrumgui.cpp | 10 ++--------
 sdrgui/gui/glspectrumgui.ui  |  4 ++--
 3 files changed, 18 insertions(+), 19 deletions(-)

diff --git a/sdrgui/gui/glspectrum.cpp b/sdrgui/gui/glspectrum.cpp
index eaf6e8b62..8c8bedc8f 100644
--- a/sdrgui/gui/glspectrum.cpp
+++ b/sdrgui/gui/glspectrum.cpp
@@ -107,7 +107,7 @@ GLSpectrum::GLSpectrum(QWidget* parent) :
 	m_histogramHoldoffBase = 4; // was 2
 	m_histogramHoldoffCount = m_histogramHoldoffBase;
 	m_histogramLateHoldoff = 20; // was 1
-	m_histogramStroke = 40; // was 4
+	m_histogramStroke = 4;
 
 	m_timeScale.setFont(font());
 	m_timeScale.setOrientation(Qt::Vertical);
@@ -175,12 +175,12 @@ void GLSpectrum::setDecay(int decay)
 
 void GLSpectrum::setHistoHoldoffBase(int holdoffBase)
 {
-	m_histogramHoldoffBase = holdoffBase < 0 ? 0 : holdoffBase > 20 ? 20 : holdoffBase;
+	m_histogramHoldoffBase = holdoffBase < 0 ? 0 : holdoffBase > 240 ? 240 : holdoffBase;
 }
 
 void GLSpectrum::setHistoStroke(int stroke)
 {
-	m_histogramStroke = stroke < 4 ? 4 : stroke > 240 ? 240 : stroke;
+	m_histogramStroke = stroke < 1 ? 1 : stroke > 40 ? 40 : stroke;
 }
 
 void GLSpectrum::setSampleRate(qint32 sampleRate)
@@ -373,7 +373,7 @@ void GLSpectrum::updateHistogram(const std::vector<Real>& spectrum)
 		{
 			for (int i = 0; i < fftMulSize; i++)
 			{
-				if (*b > 16) // was 20
+				if (*b > 20) // must be more than max value of m_decay
 				{
 					*b = *b - sub;
 				}
@@ -470,15 +470,20 @@ void GLSpectrum::updateHistogram(const std::vector<Real>& spectrum)
         }
     }
 #else
-    for(int i = 0; i < m_fftSize; i++) {
+    for (int i = 0; i < m_fftSize; i++)
+    {
         int v = (int)((spectrum[i] - m_referenceLevel) * 100.0 / m_powerRange + 100.0);
 
-        if ((v >= 0) && (v <= 99)) {
+        if ((v >= 0) && (v <= 99))
+        {
             b = m_histogram + i * 100 + v;
-            if(*b < 220)
+
+            // capping to 239 as palette values are [0..239]
+            if (*b + m_histogramStroke <= 239) {
                 *b += m_histogramStroke; // was 4
-            else if(*b < 239)
-                *b += 1;
+            } else {
+                *b = 239;
+            }
         }
     }
 #endif
diff --git a/sdrgui/gui/glspectrumgui.cpp b/sdrgui/gui/glspectrumgui.cpp
index b131664f7..1c65233d6 100644
--- a/sdrgui/gui/glspectrumgui.cpp
+++ b/sdrgui/gui/glspectrumgui.cpp
@@ -68,7 +68,7 @@ void GLSpectrumGUI::resetToDefaults()
 	m_powerRange = 100;
 	m_decay = 0;
 	m_histogramHoldoffBase = 0;
-	m_histogramStroke = 40;
+	m_histogramStroke = 4;
 	m_displayGridIntensity = 5,
 	m_displayWaterfall = true;
 	m_invertedWaterfall = false;
@@ -135,7 +135,7 @@ bool GLSpectrumGUI::deserialize(const QByteArray& data)
 		d.readBool(12, &m_invert, true);
 		d.readS32(13, &m_displayGridIntensity, 5);
 		d.readS32(14, &m_histogramHoldoffBase, 0);
-		d.readS32(15, &m_histogramStroke, 40);
+		d.readS32(15, &m_histogramStroke, 4);
 		d.readBool(16, &m_displayCurrent, false);
 		d.readS32(17, &m_displayTraceIntensity, 50);
 		Real waterfallShare;
@@ -369,9 +369,6 @@ void GLSpectrumGUI::on_decay_valueChanged(int index)
 
 void GLSpectrumGUI::on_holdoff_valueChanged(int index)
 {
-	if (index < 0) {
-		return;
-	}
 	m_histogramHoldoffBase = index;
 	//ui->holdoff->setToolTip(QString("Holdoff: %1").arg(m_histogramHoldoffBase));
 	if(m_glSpectrum != 0) {
@@ -381,9 +378,6 @@ void GLSpectrumGUI::on_holdoff_valueChanged(int index)
 
 void GLSpectrumGUI::on_stroke_valueChanged(int index)
 {
-	if (index < 4) {
-		return;
-	}
 	m_histogramStroke = index;
 	//ui->stroke->setToolTip(QString("Stroke: %1").arg(m_histogramStroke));
 	if(m_glSpectrum != 0) {
diff --git a/sdrgui/gui/glspectrumgui.ui b/sdrgui/gui/glspectrumgui.ui
index bf898392f..7dbcb01aa 100644
--- a/sdrgui/gui/glspectrumgui.ui
+++ b/sdrgui/gui/glspectrumgui.ui
@@ -93,10 +93,10 @@
         <string>Stroke:</string>
        </property>
        <property name="minimum">
-        <number>4</number>
+        <number>1</number>
        </property>
        <property name="maximum">
-        <number>240</number>
+        <number>40</number>
        </property>
        <property name="pageStep">
         <number>1</number>