Function loop

src/main.cpp:483–609

}

void loop() {
  static unsigned long maxLoopDuration = 0;
  const unsigned long loopStartTime = millis();
  static unsigned long lastMemPrint = 0;

  gpio.update();
  halTiltSensor.update(SETTINGS.tiltPageTurn, SETTINGS.orientation, activityManager.isReaderActivity());

  renderer.setFadingFix(SETTINGS.fadingFix);

  if (Serial && millis() - lastMemPrint >= 10000) {
    LOG_INF("MEM", "Free: %d bytes, Total: %d bytes, Min Free: %d bytes, MaxAlloc: %d bytes", ESP.getFreeHeap(),
            ESP.getHeapSize(), ESP.getMinFreeHeap(), ESP.getMaxAllocHeap());
    lastMemPrint = millis();
  }

  // Handle incoming serial commands,
  // nb: we use logSerial from logging to avoid deprecation warnings
  if (logSerial.available() > 0) {
    String line = logSerial.readStringUntil('\n');
    if (line.startsWith("CMD:")) {
      String cmd = line.substring(4);
      cmd.trim();
      if (cmd == "SCREENSHOT") {
        const uint32_t bufferSize = display.getBufferSize();
        logSerial.printf("SCREENSHOT_START:%d\n", bufferSize);
        uint8_t* buf = display.getFrameBuffer();
        logSerial.write(buf, bufferSize);
        logSerial.printf("SCREENSHOT_END\n");
      }
    }
  }

  // Check for any user activity (button press or release) or active background work
  static unsigned long lastActivityTime = millis();
  if (gpio.wasAnyPressed() || gpio.wasAnyReleased() || halTiltSensor.hadActivity() ||
      activityManager.preventAutoSleep()) {
    lastActivityTime = millis();         // Reset inactivity timer
    powerManager.setPowerSaving(false);  // Restore normal CPU frequency on user activity
  }

  static bool screenshotButtonsReleased = true;
  static bool screenshotComboActive = false;
  if (gpio.isPressed(HalGPIO::BTN_POWER) && gpio.isPressed(HalGPIO::BTN_DOWN)) {
    screenshotComboActive = true;
    if (screenshotButtonsReleased) {
      screenshotButtonsReleased = false;
      {
        RenderLock lock;
        ScreenshotUtil::takeScreenshot(renderer);
      }
    }
    return;
  }
  if (screenshotComboActive) {
    if (gpio.isPressed(HalGPIO::BTN_POWER)) return;
    if (gpio.wasReleased(HalGPIO::BTN_POWER)) {
      screenshotButtonsReleased = true;