From c51728154bf7d64a3e5228684c9d0c2884de15dc Mon Sep 17 00:00:00 2001
From: 3djc <5167938+3djc@users.noreply.github.com>
Date: Tue, 28 Apr 2026 03:50:22 +0200
Subject: [PATCH] fix(color): spectrum analyzer on non 480x272 screens (#7324)

---
 .../radio/radio_spectrum_analyser.cpp         | 23 +++++++----
 radio/src/telemetry/multi.cpp                 | 41 ++++---------------
 2 files changed, 22 insertions(+), 42 deletions(-)

diff --git a/radio/src/gui/colorlcd/radio/radio_spectrum_analyser.cpp b/radio/src/gui/colorlcd/radio/radio_spectrum_analyser.cpp
index f32c7e1b0..12ffa56ed 100644
--- a/radio/src/gui/colorlcd/radio/radio_spectrum_analyser.cpp
+++ b/radio/src/gui/colorlcd/radio/radio_spectrum_analyser.cpp
@@ -32,6 +32,15 @@ constexpr coord_t SPECTRUM_HEIGHT = LCD_H - EdgeTxStyles::MENU_HEADER_HEIGHT -
                                     SCALE_HEIGHT -
                                     EdgeTxStyles::UI_ELEMENT_HEIGHT;
 
+// Empirical full-scale value of bars/max/peak samples. Used to map sample
+// values to chart pixels so bars fill the available height on any LCD.
+constexpr uint8_t SPECTRUM_FULL_SCALE = 90;
+
+static inline coord_t scaleSample(uint16_t value)
+{
+  return (value * SPECTRUM_HEIGHT) / SPECTRUM_FULL_SCALE;
+}
+
 template <uint8_t CNT>
 coord_t getAverage(const uint8_t* value)
 {
@@ -39,16 +48,14 @@ coord_t getAverage(const uint8_t* value)
   for (uint8_t i = 0; i < CNT; i++) {
     sum += value[i];
   }
-  if (SPECTRUM_HEIGHT > 300) sum = sum * 2;
-  return sum / CNT;
+  return scaleSample(sum / CNT);
 }
 
 template <>
 coord_t getAverage<4>(const uint8_t* value)
 {
   uint16_t sum = value[0] + value[1] + value[2] + value[3];
-  if (SPECTRUM_HEIGHT > 300) sum = sum * 2;
-  return sum / 4;
+  return scaleSample(sum / 4);
 }
 
 class SpectrumFooterWindow : public Window
@@ -238,19 +245,17 @@ class SpectrumWindow : public Window
       lv_coord_t yv =
           SCALE_TOP - 1 -
           limit<int>(0,
-                     getAverage<step>(&reusableBuffer.spectrumAnalyser.bars[x])
-                         << 1,
+                     getAverage<step>(&reusableBuffer.spectrumAnalyser.bars[x]),
                      SCALE_TOP);
       lv_coord_t max_yv =
           SCALE_TOP - 1 -
           limit<int>(
-              0, getAverage<step>(&reusableBuffer.spectrumAnalyser.max[x]) << 1,
+              0, getAverage<step>(&reusableBuffer.spectrumAnalyser.max[x]),
               SCALE_TOP);
       lv_coord_t peak_yv =
           SCALE_TOP - 1 -
           limit<int>(0,
-                     getAverage<step>(&reusableBuffer.spectrumAnalyser.peak[x])
-                         << 1,
+                     getAverage<step>(&reusableBuffer.spectrumAnalyser.peak[x]),
                      SCALE_TOP);
 
       maxPts[i] = {x, max_yv};
diff --git a/radio/src/telemetry/multi.cpp b/radio/src/telemetry/multi.cpp
index 21cf69de2..e73ae8120 100644
--- a/radio/src/telemetry/multi.cpp
+++ b/radio/src/telemetry/multi.cpp
@@ -160,28 +160,14 @@ static void processMultiScannerPacket(const uint8_t *data, const uint8_t moduleI
     for (uint8_t channel = 0; channel <5; channel++) {
       uint8_t power = max<int>(0,(data[channel+1] - 34) >> 1); // remove everything below -120dB
 
-#if LCD_W == 480
-      coord_t x = cur_channel*2;
-      if (x < LCD_W) {
-        reusableBuffer.spectrumAnalyser.bars[x] = power;
-        if (x + 1 < LCD_W) {
-          reusableBuffer.spectrumAnalyser.bars[x + 1] = power;
-        }
-        if (power > reusableBuffer.spectrumAnalyser.max[x]) {
-          reusableBuffer.spectrumAnalyser.max[x] = power;
-          if (x + 1 < LCD_W) {
-            reusableBuffer.spectrumAnalyser.max[x + 1] = power;
-          }
-        }
-        if (power > reusableBuffer.spectrumAnalyser.peak[x]) {
-          reusableBuffer.spectrumAnalyser.peak[x] = power;
-          if (x + 1 < LCD_W) {
-            reusableBuffer.spectrumAnalyser.peak[x + 1] = power;
-          }
-        }
-#elif LCD_W == 212
-      coord_t x = cur_channel;
-      if (x < LCD_W) {
+      // Spread the (MULTI_SCANNER_MAX_CHANNEL + 1) channels across the full
+      // chart width so the spectrum fills the screen on any LCD size.
+      coord_t x_start =
+          ((coord_t)cur_channel * LCD_W) / (MULTI_SCANNER_MAX_CHANNEL + 1);
+      coord_t x_end = ((coord_t)(cur_channel + 1) * LCD_W) /
+                      (MULTI_SCANNER_MAX_CHANNEL + 1);
+      if (x_end <= x_start) x_end = x_start + 1;
+      for (coord_t x = x_start; x < x_end && x < LCD_W; x++) {
         reusableBuffer.spectrumAnalyser.bars[x] = power;
         if (power > reusableBuffer.spectrumAnalyser.max[x]) {
           reusableBuffer.spectrumAnalyser.max[x] = power;
@@ -189,17 +175,6 @@ static void processMultiScannerPacket(const uint8_t *data, const uint8_t moduleI
         if (power > reusableBuffer.spectrumAnalyser.peak[x]) {
           reusableBuffer.spectrumAnalyser.peak[x] = power;
         }
-#else
-      coord_t x = cur_channel / 2 + 1;
-      if (x < LCD_W) {
-        reusableBuffer.spectrumAnalyser.bars[x] = power;
-        if (power > reusableBuffer.spectrumAnalyser.max[x]) {
-          reusableBuffer.spectrumAnalyser.max[x] = power;
-        }
-        if (power > reusableBuffer.spectrumAnalyser.peak[x]) {
-          reusableBuffer.spectrumAnalyser.peak[x] = power;
-        }
-#endif
       }
       if (++cur_channel > MULTI_SCANNER_MAX_CHANNEL)
         cur_channel = 0;