do a full display refresh every hour

src/main.cpp

@@ -71,6 +71,7 @@ sensor_readings_t sensors_a4cf1211c3e4, sensors_246f28d1fa5c, sensors_246f28d1a0
 SensorHistory history_pressure(30);
 
 uint32_t lastDisplayUpdate = 0;
+uint32_t lastDisplayRefresh = 0;
 bool bme280_active = false;
 bool bme680_active = false;
 bool uv_active = false;
@@ -574,10 +575,17 @@ void setup()
  */
 void loop()
 {
-  /* Do an e-paper display refresh every 2 minutes */
+  /* Do an e-paper display refresh every 1 minutes */
   if (millis() - lastDisplayUpdate >= 1*60*1000) {
     lastDisplayUpdate = millis();
 
+    /* Do a full refresh every hour */
+    if (millis() - lastDisplayRefresh >= 60*60*1000) {
+      lastDisplayRefresh = millis();
+      display.clearScreen();
+      display.refresh();
+    }
+
     getSensorMeasurements();
     displayValues();
     printValues();