Added settings class with de/serialization and whiteSleepScreen setting to control inverting the sleep screen

src/CrossPointSettings.cpp

@@ -0,0 +1,46 @@
+#include "CrossPointSettings.h"
+
+#include <HardwareSerial.h>
+#include <SD.h>
+#include <Serialization.h>
+
+#include <fstream>
+
+constexpr uint8_t SETTINGS_FILE_VERSION = 1;
+constexpr char SETTINGS_FILE[] = "/sd/.crosspoint/settings.bin";
+
+bool CrossPointSettings::saveToFile() const {
+  // Make sure the directory exists
+  SD.mkdir("/.crosspoint");
+  
+  std::ofstream outputFile(SETTINGS_FILE);
+  serialization::writePod(outputFile, SETTINGS_FILE_VERSION);
+  serialization::writePod(outputFile, whiteSleepScreen);
+  outputFile.close();
+  
+  Serial.printf("[%lu] [CPS] Settings saved to file\n", millis());
+  return true;
+}
+
+bool CrossPointSettings::loadFromFile() {
+  if (!SD.exists(SETTINGS_FILE + 3)) {  // +3 to skip "/sd" prefix
+    Serial.printf("[%lu] [CPS] Settings file does not exist, using defaults\n", millis());
+    return false;
+  }
+
+  std::ifstream inputFile(SETTINGS_FILE);
+
+  uint8_t version;
+  serialization::readPod(inputFile, version);
+  if (version != SETTINGS_FILE_VERSION) {
+    Serial.printf("[%lu] [CPS] Deserialization failed: Unknown version %u\n", millis(), version);
+    inputFile.close();
+    return false;
+  }
+
+  serialization::readPod(inputFile, whiteSleepScreen);
+
+  inputFile.close();
+  Serial.printf("[%lu] [CPS] Settings loaded from file\n", millis());
+  return true;
+}

src/CrossPointSettings.h

@@ -0,0 +1,13 @@
+#pragma once
+#include <iosfwd>
+
+class CrossPointSettings {
+ public:
+  // Sleep screen settings
+  bool whiteSleepScreen = false;
+  
+  ~CrossPointSettings() = default;
+
+  bool saveToFile() const;
+  bool loadFromFile();
+};

src/main.cpp

@@ -14,6 +14,7 @@
 #include <builtinFonts/ubuntu_bold_10.h>
 
 #include "Battery.h"
+#include "CrossPointSettings.h"
 #include "CrossPointState.h"
 #include "config.h"
 #include "screens/BootLogoScreen.h"
@@ -41,6 +42,7 @@ InputManager inputManager;
 GfxRenderer renderer(einkDisplay);
 Screen* currentScreen;
 CrossPointState appState;
+CrossPointSettings appSettings;
 
 // Fonts
 EpdFont bookerlyFont(&bookerly_2b);
@@ -131,7 +133,8 @@ void waitForPowerRelease() {
 // Enter deep sleep mode
 void enterDeepSleep() {
   exitScreen();
-  enterNewScreen(new SleepScreen(renderer, inputManager));
+  appSettings.saveToFile();
+  enterNewScreen(new SleepScreen(renderer, inputManager, appSettings));
 
   Serial.printf("[%lu] [   ] Power button released after a long press. Entering deep sleep.\n", millis());
   delay(1000);  // Allow Serial buffer to empty and display to update
@@ -199,6 +202,7 @@ void setup() {
   // SD Card Initialization
   SD.begin(SD_SPI_CS, SPI, SPI_FQ);
 
+  appSettings.loadFromFile();
   appState.loadFromFile();
   if (!appState.openEpubPath.empty()) {
     auto epub = loadEpub(appState.openEpubPath);

src/screens/SleepScreen.cpp

@@ -4,6 +4,7 @@
 
 #include "config.h"
 #include "images/CrossLarge.h"
+#include "CrossPointSettings.h"
 
 void SleepScreen::onEnter() {
   const auto pageWidth = GfxRenderer::getScreenWidth();
@@ -13,6 +14,11 @@ void SleepScreen::onEnter() {
   renderer.drawImage(CrossLarge, (pageWidth - 128) / 2, (pageHeight - 128) / 2, 128, 128);
   renderer.drawCenteredText(UI_FONT_ID, pageHeight / 2 + 70, "CrossPoint", true, BOLD);
   renderer.drawCenteredText(SMALL_FONT_ID, pageHeight / 2 + 95, "SLEEPING");
-  // renderer.invertScreen();
+
+  // Apply white screen if enabled in settings
+  if (!settings.whiteSleepScreen) {
+    renderer.invertScreen();
+  }
+
   renderer.displayBuffer(EInkDisplay::HALF_REFRESH);
 }

src/screens/SleepScreen.h

@@ -1,8 +1,14 @@
 #pragma once
 #include "Screen.h"
 
+class CrossPointSettings;
+
 class SleepScreen final : public Screen {
  public:
-  explicit SleepScreen(GfxRenderer& renderer, InputManager& inputManager) : Screen(renderer, inputManager) {}
+  explicit SleepScreen(GfxRenderer& renderer, InputManager& inputManager, const CrossPointSettings& settings)
+      : Screen(renderer, inputManager), settings(settings) {}
   void onEnter() override;
+
+ private:
+  const CrossPointSettings& settings;
 };