Add dark color scheme, backlight timeout, and L/R swap feature

- Invert UI colors: black background with white text, yellow highlights
- Add 30-second backlight timeout with auto-wake on button press
- Add Swap L/R menu option with checkbox to swap audio channels
- Update volume page styling (yellow bar, full-screen container)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

main/bt_app.c

@@ -35,7 +35,7 @@
 
 /* device name */
 #define TARGET_DEVICE_NAME    "ESP_SPEAKER"
-#define LOCAL_DEVICE_NAME     "ESP_A2DP_SRC"
+#define LOCAL_DEVICE_NAME     "SOUNDSHOT"
 
 /* AVRCP used transaction label */
 #define APP_RC_CT_TL_GET_CAPS            (0)
@@ -798,6 +798,8 @@ void generate_exp(uint8_t *buf, int len, float balance)
     //float rate_hz = MIN_RATE_HZ * powf(MAX_RATE_HZ / MIN_RATE_HZ, abs_balance);
     float samples_per_click = SAMPLE_RATE / rate_hz;
 
+    bool swap_lr = system_getSwapLR();
+
     for (int i = 0; i < samples_needed; i++) {
         int16_t left = 0;
         int16_t right = 0;
@@ -814,8 +816,13 @@ void generate_exp(uint8_t *buf, int len, float balance)
 
         click_timer -= 1.0f;
 
-        samples[i * 2 + 0] = left;
+        if (swap_lr) {
-        samples[i * 2 + 1] = right;
+            samples[i * 2 + 0] = right;
+            samples[i * 2 + 1] = left;
+        } else {
+            samples[i * 2 + 0] = left;
+            samples[i * 2 + 1] = right;
+        }
 
     }
 }

main/gui.c

@@ -65,6 +65,8 @@ static void createBubble(lv_obj_t * scr);
 static void build_scrollable_menu(void);
 static void currentFocusIndex(menu_context_t *ctx);
 static lv_obj_t * addMenuItem(lv_obj_t *page, const char *text);
+static lv_obj_t * addMenuItemWithCheckbox(lv_obj_t *page, const char *text, bool checked, lv_obj_t **checkbox_out);
+static void update_checkbox_focus_style(lv_obj_t *cb, bool focused);
 static lv_obj_t* create_menu_container(void);
 static void show_bt_device_list(void);
 static void show_volume_control(void);
@@ -103,6 +105,19 @@ static lv_obj_t *_currentPage = NULL;
 
 static GuiMode_t _mode = GUI_BUBBLE;
 
+// Backlight timeout
+#define BACKLIGHT_TIMEOUT_MS    30000
+static TickType_t _lastButtonPress = 0;
+static bool _backlightOn = true;
+
+static void backlight_reset_timeout(void) {
+    _lastButtonPress = xTaskGetTickCount();
+    if (!_backlightOn) {
+        gpio_set_level(PIN_NUM_BK_LIGHT, 1);
+        _backlightOn = true;
+    }
+}
+
 // Menu navigation stack
 #define MAX_MENU_STACK_SIZE 8
 typedef struct {
@@ -137,6 +152,9 @@ static int _current_volume = 50; // Default volume (0-100)
 static lv_obj_t* _calibration_page = NULL;
 static lv_timer_t* _calibration_timer = NULL;
 
+// Swap L/R checkbox
+static lv_obj_t* _swapLR_checkbox = NULL;
+
 // Hide *all* headers/back buttons that LVGL may show for this menu
 static void menu_hide_headers(lv_obj_t *menu) {
     if (!menu) return;
@@ -200,6 +218,7 @@ static lv_obj_t* create_main_page(void) {
 
     addMenuItem(main_page, "Calibration");
     addMenuItem(main_page, "Volume");
+    addMenuItemWithCheckbox(main_page, "Swap L/R", system_getSwapLR(), &_swapLR_checkbox);
     //addMenuItem(main_page, "About");
     addMenuItem(main_page, "Exit");
 
@@ -238,6 +257,7 @@ static void cleanup_menu(void) {
         _volume_page = NULL;
         _volume_bar = NULL;
         _volume_label = NULL;
+        _swapLR_checkbox = NULL;
         if (_calibration_timer) {
             lv_timer_del(_calibration_timer);
             _calibration_timer = NULL;
@@ -257,7 +277,9 @@ static void create_lvgl_demo(void)
     lvgl_port_lock(0);
     // Create a screen with black background
     lv_obj_t *scr = lv_scr_act();
-    
+    lv_obj_set_style_bg_color(scr, lv_color_black(), 0);
+    lv_obj_set_style_bg_opa(scr, LV_OPA_COVER, 0);
+
     createBubble(scr);
     // Menu will be created lazily when needed
 
@@ -462,6 +484,14 @@ static void btn_click_cb(lv_event_t * e) {
         menu_stack_push(_currentPage);
         show_volume_control();
         UNLOCK();
+    } else if (strcmp(txt, "Swap L/R") == 0) {
+        // Toggle the swap L/R state
+        system_toggleSwapLR();
+        // Update the checkbox visual (now a label showing "X" or empty)
+        if (_swapLR_checkbox) {
+            lv_label_set_text(_swapLR_checkbox, system_getSwapLR() ? "X" : "");
+        }
+        ESP_LOGI(TAG, "Swap L/R toggled to: %s", system_getSwapLR() ? "ON" : "OFF");
     } else if (strcmp(txt, "Back") == 0) {
         LOCK();
         menu_go_back();
@@ -498,18 +528,18 @@ static void refresh_highlight(void) {
 
         if (lv_obj_has_flag(child, LV_OBJ_FLAG_USER_1))
         {
-            lv_obj_set_style_bg_color(child, lv_color_hex(0xFF8800), 0);
+            lv_obj_set_style_bg_color(child, lv_color_hex(0xFFFF00), 0);
                 lv_obj_set_style_text_color(lv_obj_get_child(child,0),
-                                            lv_color_white(), 0);
+                                            lv_color_black(), 0);
 
             selected = child;
             ESP_LOGI(TAG, "Selected");
         }
-        else 
+        else
         {
-            lv_obj_set_style_bg_color(child, lv_color_white(), 0);
+            lv_obj_set_style_bg_color(child, lv_color_black(), 0);
             lv_obj_set_style_text_color(lv_obj_get_child(child,0),
-                                        lv_color_black(), 0);
+                                        lv_color_white(), 0);
         }
 
         index++;
@@ -560,6 +590,12 @@ static void menuInc(int inc)
             // Update scroll on old focused item (stop scrolling)
             update_label_scroll(_menuContext.obj, false);
 
+            // Update checkbox style on old focused item (if it has one)
+            lv_obj_t *old_cb = lv_obj_get_user_data(_menuContext.obj);
+            if (old_cb) {
+                update_checkbox_focus_style(old_cb, false);
+            }
+
             lv_obj_add_state(next, LV_STATE_FOCUSED);
             lv_obj_clear_state(_menuContext.obj, LV_STATE_FOCUSED);
             lv_obj_scroll_to_view(next, LV_ANIM_ON);
@@ -567,6 +603,12 @@ static void menuInc(int inc)
             // Update scroll on new focused item (start scrolling)
             update_label_scroll(next, true);
 
+            // Update checkbox style on new focused item (if it has one)
+            lv_obj_t *new_cb = lv_obj_get_user_data(next);
+            if (new_cb) {
+                update_checkbox_focus_style(new_cb, true);
+            }
+
             _menuContext.obj = next;
             _menuContext.selected = search_index;
         }
@@ -626,6 +668,83 @@ static void label_scroll_focus_cb(lv_event_t * e)
     }
 }
 
+static lv_obj_t * addMenuItemWithCheckbox(lv_obj_t *page, const char *text, bool checked, lv_obj_t **checkbox_out)
+{
+    if (!page || !text) {
+        ESP_LOGE(TAG, "Null parameters in addMenuItemWithCheckbox");
+        return NULL;
+    }
+
+    // Ensure styles are initialized
+    ensure_menu_styles();
+
+    lv_obj_t * btn = lv_btn_create(page);
+    if (!btn) {
+        ESP_LOGE(TAG, "Failed to create button in addMenuItemWithCheckbox");
+        return NULL;
+    }
+
+    lv_obj_set_size(btn, LV_PCT(100), ROW_H);
+
+    lv_obj_add_style(btn, &_styleUnfocusedBtn, LV_PART_MAIN | LV_STATE_DEFAULT);
+    lv_obj_add_style(btn, &_styleFocusedBtn, LV_PART_MAIN | LV_STATE_FOCUSED);
+
+    lv_obj_add_state(btn, LV_STATE_DEFAULT);
+
+    lv_obj_set_style_radius(btn, 0, LV_PART_MAIN);
+    lv_obj_set_style_border_width(btn, 0, LV_PART_MAIN);
+    lv_obj_clear_flag(btn, LV_OBJ_FLAG_SCROLLABLE);
+
+    // Label on the left (same as regular menu item)
+    lv_obj_t * lbl = lv_label_create(btn);
+    if (!lbl) {
+        ESP_LOGE(TAG, "Failed to create label in addMenuItemWithCheckbox");
+        lv_obj_del(btn);
+        return NULL;
+    }
+
+    lv_label_set_text(lbl, text);
+    lv_label_set_long_mode(lbl, LV_LABEL_LONG_CLIP);
+    lv_obj_set_width(lbl, LV_PCT(80));
+    lv_obj_set_style_radius(lbl, 0, LV_PART_MAIN | LV_STATE_ANY);
+    lv_obj_set_style_border_width(lbl, 0, LV_PART_MAIN | LV_STATE_ANY);
+    lv_obj_align(lbl, LV_ALIGN_LEFT_MID, 0, 0);
+
+    // Label on the right to act as checkbox (shows "X" when checked, empty when not)
+    lv_obj_t * cb = lv_label_create(btn);
+    lv_label_set_text(cb, checked ? "X" : "");
+    lv_obj_set_style_text_color(cb, lv_color_white(), 0);  // Unfocused: white
+    lv_obj_align(cb, LV_ALIGN_RIGHT_MID, -4, 0);
+
+    if (checkbox_out) {
+        *checkbox_out = cb;
+    }
+
+    // Add focus event handler to control scrolling
+    lv_obj_add_event_cb(btn, label_scroll_focus_cb, LV_EVENT_ALL, NULL);
+
+    // click callback
+    lv_obj_add_event_cb(btn, btn_click_cb, LV_EVENT_CLICKED, NULL);
+
+    // Store checkbox in user data for focus styling updates
+    lv_obj_set_user_data(btn, cb);
+
+    return btn;
+}
+
+// Update checkbox label color based on parent focus state
+static void update_checkbox_focus_style(lv_obj_t *cb, bool focused) {
+    if (!cb) return;
+
+    if (focused) {
+        // Focused: black text (on yellow background)
+        lv_obj_set_style_text_color(cb, lv_color_black(), 0);
+    } else {
+        // Unfocused: white text (on black background)
+        lv_obj_set_style_text_color(cb, lv_color_white(), 0);
+    }
+}
+
 static lv_obj_t * addMenuItem(lv_obj_t *page, const char *text)
 {
     if (!page || !text) {
@@ -719,12 +838,12 @@ static void ensure_menu_styles(void) {
         lv_style_init(&_styleFocusedBtn);
         lv_style_init(&_styleUnfocusedBtn);
 
-        lv_style_set_bg_color(&_styleUnfocusedBtn, lv_color_make(0xff,0xff,0xff));  // white bg
+        lv_style_set_bg_color(&_styleUnfocusedBtn, lv_color_make(0x00,0x00,0x00));  // black bg
-        lv_style_set_text_color(&_styleUnfocusedBtn, lv_color_black());       // black text
+        lv_style_set_text_color(&_styleUnfocusedBtn, lv_color_white());       // white text
         //lv_style_set_text_font(&_styleUnfocusedBtn, &lv_font_unscii_16);  // larger font
 
-        lv_style_set_bg_color(&_styleFocusedBtn, lv_color_make(0x33,0x99,0xFF));    // blue bg
+        lv_style_set_bg_color(&_styleFocusedBtn, lv_color_make(0xFF,0xFF,0x00));    // bright yellow bg
-        lv_style_set_text_color(&_styleFocusedBtn, lv_color_white());               // white text
+        lv_style_set_text_color(&_styleFocusedBtn, lv_color_black());               // black text
         //lv_style_set_text_font(&_styleFocusedBtn, &lv_font_unscii_16);     // larger font
         
         styles_initialized = true;
@@ -1066,9 +1185,9 @@ static lv_obj_t* create_bt_device_page(bool start_discovery) {
         lv_label_set_text(_bt_status_item, "Devices:");
         lv_obj_set_width(_bt_status_item, lv_pct(100));
         lv_obj_set_height(_bt_status_item, 16);  // Thinner header
-        lv_obj_set_style_bg_color(_bt_status_item, lv_color_make(0xE0, 0xE0, 0xE0), 0);
+        lv_obj_set_style_bg_color(_bt_status_item, lv_color_make(0x00, 0x00, 0x00), 0);
         lv_obj_set_style_bg_opa(_bt_status_item, LV_OPA_COVER, 0);
-        lv_obj_set_style_text_color(_bt_status_item, lv_color_black(), 0);
+        lv_obj_set_style_text_color(_bt_status_item, lv_color_white(), 0);
         lv_obj_set_style_pad_left(_bt_status_item, 5, 0);
         lv_obj_set_style_pad_top(_bt_status_item, 2, 0);
         lv_obj_set_style_text_align(_bt_status_item, LV_TEXT_ALIGN_LEFT, 0);
@@ -1086,7 +1205,7 @@ static lv_obj_t* create_bt_device_page(bool start_discovery) {
         lv_obj_set_style_outline_width(_bt_device_container, 0, LV_PART_MAIN);
         lv_obj_set_style_pad_all(_bt_device_container, 0, LV_PART_MAIN);
         lv_obj_set_style_pad_row(_bt_device_container, 0, LV_PART_MAIN);
-        lv_obj_set_style_bg_color(_bt_device_container, lv_color_white(), LV_PART_MAIN);
+        lv_obj_set_style_bg_color(_bt_device_container, lv_color_black(), LV_PART_MAIN);
         lv_obj_set_style_bg_opa(_bt_device_container, LV_OPA_COVER, LV_PART_MAIN);
         lv_obj_set_flex_flow(_bt_device_container, LV_FLEX_FLOW_COLUMN);
         lv_obj_set_scrollbar_mode(_bt_device_container, LV_SCROLLBAR_MODE_AUTO);
@@ -1235,9 +1354,11 @@ static lv_obj_t* create_volume_page(void) {
 
     // Create a container to center everything vertically
     lv_obj_t* container = lv_obj_create(_volume_page);
-    lv_obj_set_size(container, lv_pct(100), LV_SIZE_CONTENT);
+    lv_obj_set_size(container, lv_pct(100), lv_pct(100));
-    lv_obj_set_style_bg_opa(container, LV_OPA_TRANSP, 0);
+    lv_obj_set_style_bg_color(container, lv_color_black(), 0);
+    lv_obj_set_style_bg_opa(container, LV_OPA_COVER, 0);
     lv_obj_set_style_border_width(container, 0, 0);
+    lv_obj_set_style_radius(container, 0, 0);
     lv_obj_set_style_pad_all(container, 0, 0);
     lv_obj_set_flex_flow(container, LV_FLEX_FLOW_COLUMN);
     lv_obj_set_flex_align(container, LV_FLEX_ALIGN_CENTER, LV_FLEX_ALIGN_CENTER, LV_FLEX_ALIGN_CENTER);
@@ -1247,7 +1368,7 @@ static lv_obj_t* create_volume_page(void) {
     lv_obj_t* title = lv_label_create(container);
     lv_label_set_text(title, "Volume Control");
     lv_obj_set_style_text_align(title, LV_TEXT_ALIGN_CENTER, 0);
-    lv_obj_set_style_text_color(title, lv_color_black(), 0);
+    lv_obj_set_style_text_color(title, lv_color_white(), 0);
     lv_obj_set_style_pad_bottom(title, 8, 0);
 
     // Create volume bar (progress bar)
@@ -1255,6 +1376,8 @@ static lv_obj_t* create_volume_page(void) {
     lv_obj_set_size(_volume_bar, 120, 20);
     lv_bar_set_range(_volume_bar, 0, 100);
     lv_bar_set_value(_volume_bar, _current_volume, LV_ANIM_OFF);
+    lv_obj_set_style_bg_color(_volume_bar, lv_color_make(0x40, 0x40, 0x40), LV_PART_MAIN);  // Dark gray background
+    lv_obj_set_style_bg_color(_volume_bar, lv_color_make(0xFF, 0xFF, 0x00), LV_PART_INDICATOR);  // Yellow indicator
     lv_obj_set_style_pad_top(_volume_bar, 5, 0);
     lv_obj_set_style_pad_bottom(_volume_bar, 5, 0);
 
@@ -1264,6 +1387,7 @@ static lv_obj_t* create_volume_page(void) {
     snprintf(volume_text, sizeof(volume_text), "%d%%", _current_volume);
     lv_label_set_text(_volume_label, volume_text);
     lv_obj_set_style_text_align(_volume_label, LV_TEXT_ALIGN_CENTER, 0);
+    lv_obj_set_style_text_color(_volume_label, lv_color_white(), 0);
     lv_obj_set_style_pad_top(_volume_label, 5, 0);
 
     return _volume_page;
@@ -1438,7 +1562,7 @@ static void calibration_click_cb(lv_event_t * e) {
             // Show "Calibrated" message centered
             lv_obj_t* label = lv_label_create(container);
             lv_label_set_text(label, "Calibrated");
-            lv_obj_set_style_text_color(label, lv_color_black(), 0);
+            lv_obj_set_style_text_color(label, lv_color_white(), 0);
             lv_obj_set_style_text_font(label, &lv_font_montserrat_14, 0);
             lv_obj_center(label);
         }
@@ -1467,7 +1591,7 @@ static void calibration_click_cb(lv_event_t * e) {
             // Show "Cleared" message centered
             lv_obj_t* label = lv_label_create(container);
             lv_label_set_text(label, "Cleared");
-            lv_obj_set_style_text_color(label, lv_color_black(), 0);
+            lv_obj_set_style_text_color(label, lv_color_white(), 0);
             lv_obj_set_style_text_font(label, &lv_font_montserrat_14, 0);
             lv_obj_center(label);
         }
@@ -1556,11 +1680,11 @@ static void build_scrollable_menu(void) {
     lv_style_init(&_styleFocusedBtn);
     lv_style_init(&_styleUnfocusedBtn);
 
-    lv_style_set_bg_color(&_styleUnfocusedBtn, lv_color_make(0xff,0xff,0xff));  // gray bg
+    lv_style_set_bg_color(&_styleUnfocusedBtn, lv_color_make(0x00,0x00,0x00));  // black bg
-    lv_style_set_text_color(&_styleUnfocusedBtn, lv_color_hex(0xFF8800));
+    lv_style_set_text_color(&_styleUnfocusedBtn, lv_color_white());
 
-    lv_style_set_bg_color(&_styleFocusedBtn, lv_color_make(0x33,0x99,0xFF)); // blue bg
+    lv_style_set_bg_color(&_styleFocusedBtn, lv_color_make(0xFF,0xFF,0x00)); // bright yellow bg
-    lv_style_set_text_color(&_styleUnfocusedBtn,lv_color_black());
+    lv_style_set_text_color(&_styleFocusedBtn, lv_color_black());
 
 
     // 2) Inside it, create the lv_menu and hide its sidebar/header
@@ -1653,13 +1777,28 @@ static void gui_task(void *pvParameters)
     lv_obj_remove_flag(_bubble, LV_OBJ_FLAG_HIDDEN);
     UNLOCK();
 
+    // Initialize backlight timeout
+    _lastButtonPress = xTaskGetTickCount();
+    _backlightOn = true;
+
     ESP_LOGI(TAG, "Start GUI Task...");
     while (1)
     {
-        
+        // Check backlight timeout
+        if (_backlightOn) {
+            TickType_t elapsed = xTaskGetTickCount() - _lastButtonPress;
+            if (elapsed > pdMS_TO_TICKS(BACKLIGHT_TIMEOUT_MS)) {
+                gpio_set_level(PIN_NUM_BK_LIGHT, 0);
+                _backlightOn = false;
+                ESP_LOGI(TAG, "Backlight off due to timeout");
+            }
+        }
 
-        if (xQueueReceive(q, &ev, pdMS_TO_TICKS(10)) == pdTRUE) 
+        if (xQueueReceive(q, &ev, pdMS_TO_TICKS(10)) == pdTRUE)
         {
+            // Reset backlight timeout on any button press
+            backlight_reset_timeout();
+
             switch (ev) {
 #if 0
                 case (KEY_UP << KEY_LONG_PRESS):

main/system.c

@@ -23,6 +23,7 @@ void system_init(void)
     _systemState.primaryAxis = PRIMARY_AXIS;
     _systemState.pairedDeviceCount = 0;
     _systemState.isCharging = false;
+    _systemState.swapLR = false;
 
 	_systemEvent = xEventGroupCreate();
 
@@ -74,6 +75,31 @@ bool system_getChargeStatus(void)
     return charging;
 }
 
+void system_setSwapLR(bool swap)
+{
+    xSemaphoreTake(_eventManager.mutex, portMAX_DELAY);
+    _systemState.swapLR = swap;
+    xSemaphoreGive(_eventManager.mutex);
+    ESP_LOGI("system", "Swap L/R: %s", swap ? "ON" : "OFF");
+}
+
+bool system_getSwapLR(void)
+{
+    bool swap;
+    xSemaphoreTake(_eventManager.mutex, portMAX_DELAY);
+    swap = _systemState.swapLR;
+    xSemaphoreGive(_eventManager.mutex);
+    return swap;
+}
+
+void system_toggleSwapLR(void)
+{
+    xSemaphoreTake(_eventManager.mutex, portMAX_DELAY);
+    _systemState.swapLR = !_systemState.swapLR;
+    ESP_LOGI("system", "Swap L/R toggled: %s", _systemState.swapLR ? "ON" : "OFF");
+    xSemaphoreGive(_eventManager.mutex);
+}
+
 void system_setZeroAngle(void)
 {
     xSemaphoreTake(_eventManager.mutex, portMAX_DELAY);

main/system.h

@@ -55,6 +55,9 @@ typedef struct SystemState_s
     // Charge status
     bool isCharging;
 
+    // Swap L/R audio channels
+    bool swapLR;
+
 } SystemState_t;
 
 
@@ -90,6 +93,10 @@ float system_getAngle(void);
 void system_setChargeStatus(bool charging);
 bool system_getChargeStatus(void);
 
+void system_setSwapLR(bool swap);
+bool system_getSwapLR(void);
+void system_toggleSwapLR(void);
+
 void system_setZeroAngle(void);
 void system_clearZeroAngle(void);
 float system_getZeroAngle(void);