feat(eink): full refresh interval setting in Settings › Display

Add "Full rfsh" setting (e-ink only) with options off/5/10/20/30
partial refreshes between full refreshes. Prevents ghosting on panels
that accumulate artifacts after many partial updates.

GxEPDDisplay counts partial refreshes and calls display.display(false)
every N frames when the interval is set. Persisted in DataStore and
applied at startup via applyFullRefreshInterval().

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

examples/companion_radio/DataStore.cpp

@@ -295,6 +295,7 @@ void DataStore::loadPrefsInt(const char *filename, NodePrefs& _prefs, double& no
   rd(&_prefs.display_rotation,          sizeof(_prefs.display_rotation));
   rd(_prefs.page_order,                 sizeof(_prefs.page_order));
   rd(&_prefs.joystick_rotation,         sizeof(_prefs.joystick_rotation));
+  rd(&_prefs.eink_full_refresh_every,   sizeof(_prefs.eink_full_refresh_every));
 
   file.close();
 }
@@ -374,6 +375,7 @@ void DataStore::savePrefs(const NodePrefs& _prefs, double node_lat, double node_
     file.write((uint8_t *)&_prefs.display_rotation, sizeof(_prefs.display_rotation));
     file.write((uint8_t *)_prefs.page_order, sizeof(_prefs.page_order));
     file.write((uint8_t *)&_prefs.joystick_rotation, sizeof(_prefs.joystick_rotation));
+    file.write((uint8_t *)&_prefs.eink_full_refresh_every, sizeof(_prefs.eink_full_refresh_every));
 
     file.close();
   }

examples/companion_radio/NodePrefs.h

@@ -85,6 +85,7 @@ struct NodePrefs {  // persisted to file
   // 0 = end of list (also uninitialized legacy). hasCustomOrder iff page_order[0] in 1..11.
   uint8_t  page_order[11];
   uint8_t  joystick_rotation;   // 0-3 steps CW; independent of display_rotation
+  uint8_t  eink_full_refresh_every; // index into {0,5,10,20,30}: full refresh every N partials (0=off)
 
   // Bitmasks for home_pages_mask (bit=1 → page visible; 0 field = all visible).
   static const uint16_t HP_CLOCK     = 1 << 0;

examples/companion_radio/ui-new/SettingsScreen.h

@@ -26,6 +26,9 @@ class SettingsScreen : public UIScreen {
 #endif
 #if defined(EINK_DISPLAY_MODEL)
     JOY_ROTATION,
+#endif
+#if defined(EINK_DISPLAY_MODEL)
+    EINK_FULL_REFRESH,
 #endif
     // Sound section
     SECTION_SOUND,
@@ -85,6 +88,10 @@ class SettingsScreen : public UIScreen {
   static const int LOW_BAT_COUNT = 7;
   static const char* BATT_DISPLAY_LABELS[3];
   static const int BATT_DISPLAY_COUNT = 3;
+#if defined(EINK_DISPLAY_MODEL)
+  static const char* EINK_FULL_REFRESH_LABELS[5];
+  static const int   EINK_FULL_REFRESH_COUNT = 5;
+#endif
 
   int lowBatIndex() {
     NodePrefs* p = _task->getNodePrefs();
@@ -438,6 +445,14 @@ class SettingsScreen : public UIScreen {
       { static const char* ROT_LABELS[] = { "0 deg", "90 deg", "180 deg", "270 deg" };
         uint8_t r = p ? (p->joystick_rotation & 3) : 0;
         display.print(ROT_LABELS[r]); }
+#endif
+#if defined(EINK_DISPLAY_MODEL)
+    } else if (item == EINK_FULL_REFRESH) {
+      display.print("Full rfsh");
+      display.setCursor(display.valCol(), y);
+      { uint8_t idx = p ? p->eink_full_refresh_every : 0;
+        if (idx >= EINK_FULL_REFRESH_COUNT) idx = 0;
+        display.print(EINK_FULL_REFRESH_LABELS[idx]); }
 #endif
     } else if (item == DM_FILTER) {
       display.print("DM");
@@ -669,6 +684,17 @@ public:
       _dirty = true;
       return true;
     }
+#endif
+#if defined(EINK_DISPLAY_MODEL)
+    if (_selected == EINK_FULL_REFRESH && p && (left || right || enter)) {
+      int idx = p->eink_full_refresh_every;
+      if (idx >= EINK_FULL_REFRESH_COUNT) idx = 0;
+      idx = (idx + (left ? EINK_FULL_REFRESH_COUNT - 1 : 1)) % EINK_FULL_REFRESH_COUNT;
+      p->eink_full_refresh_every = idx;
+      _task->applyFullRefreshInterval();
+      _dirty = true;
+      return true;
+    }
 #endif
     if (_selected == DM_FILTER && p && (left || right || enter)) {
       p->dm_show_all = p->dm_show_all ? 0 : 1;
@@ -702,3 +728,6 @@ const char*    SettingsScreen::GPS_INTERVAL_LABELS[6] = { "off", "30s", "1min",
 const uint16_t SettingsScreen::LOW_BAT_OPTS[7]   = { 0, 3000, 3100, 3200, 3300, 3400, 3500 };
 const char*    SettingsScreen::LOW_BAT_LABELS[7]  = { "off", "3.0V", "3.1V", "3.2V", "3.3V", "3.4V", "3.5V" };
 const char*    SettingsScreen::BATT_DISPLAY_LABELS[3] = { "icon", "%", "V" };
+#if defined(EINK_DISPLAY_MODEL)
+const char* SettingsScreen::EINK_FULL_REFRESH_LABELS[5] = { "off", "5", "10", "20", "30" };
+#endif

examples/companion_radio/ui-new/UITask.cpp

@@ -903,6 +903,7 @@ void UITask::begin(DisplayDriver* display, SensorManager* sensors, NodePrefs* no
   applyBrightness();
   applyFont();
   applyRotation();
+  applyFullRefreshInterval();
   setCurrScreen(splash);
 }
 
@@ -1662,6 +1663,16 @@ void UITask::applyRotation() {
   }
 }
 
+void UITask::applyFullRefreshInterval() {
+  if (_display != NULL && _node_prefs != NULL) {
+    static const uint8_t OPTS[] = { 0, 5, 10, 20, 30 };
+    static const int OPTS_COUNT = 5;
+    uint8_t idx = _node_prefs->eink_full_refresh_every;
+    if (idx >= OPTS_COUNT) idx = 0;
+    _display->setFullRefreshInterval(OPTS[idx]);
+  }
+}
+
 void UITask::setBrightnessLevel(uint8_t level) {
   if (_node_prefs == NULL) return;
   if (level > 4) level = 4;

examples/companion_radio/ui-new/UITask.h

@@ -161,6 +161,7 @@ public:
   void applyGPSInterval();
   void applyFont();
   void applyRotation();
+  void applyFullRefreshInterval();
   uint32_t autoOffMillis() const {
     if (!_node_prefs || _node_prefs->auto_off_secs == 0) return 0;
     return (uint32_t)_node_prefs->auto_off_secs * 1000UL;

src/helpers/ui/DisplayDriver.h

@@ -228,5 +228,6 @@ public:
   
   virtual void setBrightness(uint8_t level) { }  // level 0-4 (min to max), no-op default
   virtual void setDisplayRotation(uint8_t rot) { }  // 0-3, no-op for fixed-orientation displays
+  virtual void setFullRefreshInterval(uint8_t n) { }  // e-ink: do full refresh every n partial refreshes (0=never)
   virtual void endFrame() = 0;
 };

src/helpers/ui/GxEPDDisplay.cpp

@@ -195,7 +195,12 @@ void GxEPDDisplay::setDisplayRotation(uint8_t rot) {
 void GxEPDDisplay::endFrame() {
   uint32_t crc = display_crc.finalize();
   if (crc != last_display_crc_value) {
-    display.display(true);
+    bool partial = true;
+    if (_full_refresh_interval > 0 && ++_partial_count >= _full_refresh_interval) {
+      partial = false;
+      _partial_count = 0;
+    }
+    display.display(partial);
     last_display_crc_value = crc;
   }
 }

src/helpers/ui/GxEPDDisplay.h

@@ -54,6 +54,8 @@ class GxEPDDisplay : public DisplayDriver {
   CRC32 display_crc;
   int last_display_crc_value = 0;
   int _text_sz = 1;
+  uint8_t _full_refresh_interval = 0;  // 0=never, N=full refresh every N partial refreshes
+  uint8_t _partial_count = 0;
 
 public:
 #if defined(EINK_DISPLAY_MODEL)
@@ -100,5 +102,6 @@ public:
   void drawXbm(int x, int y, const uint8_t* bits, int w, int h) override;
   uint16_t getTextWidth(const char* str) override;
   void setDisplayRotation(uint8_t rot) override;
+  void setFullRefreshInterval(uint8_t n) override { _full_refresh_interval = n; _partial_count = 0; }
   void endFrame() override;
 };