Add firmware font size setting

Tactility/Source/lvgl/Lvgl.cpp

@@ -13,6 +13,7 @@
 #include <tactility/device.h>
 #include <tactility/drivers/backlight.h>
 #include <tactility/log.h>
+#include <tactility/lvgl_fonts.h>
 #include <tactility/lvgl_module.h>
 #include <tactility/lvgl_pointer.h>
 #include <tactility/module.h>
@@ -27,6 +28,49 @@ bool isStarted() {
     return module_is_started(&lvgl_module);
 }
 
+void applyFontSize(settings::display::FontSize fontSize) {
+    LvglFontScale scale;
+    switch (fontSize) {
+        using enum settings::display::FontSize;
+        case Small:
+            scale = FONT_SCALE_SMALL;
+            break;
+        case Large:
+            scale = FONT_SCALE_LARGE;
+            break;
+        case Default:
+        default:
+            scale = FONT_SCALE_DEFAULT;
+            break;
+    }
+
+    lvgl_set_text_font_scale(scale);
+    const lv_font_t* font = lvgl_get_text_font(FONT_SIZE_DEFAULT);
+
+    for (lv_display_t* display = lv_display_get_next(nullptr);
+         display != nullptr;
+         display = lv_display_get_next(display)) {
+#if LV_USE_THEME_DEFAULT
+        if (lv_display_get_theme(display) == lv_theme_default_get()) {
+            lv_obj_t* screen = lv_display_get_screen_active(display);
+            lv_theme_default_init(
+                display,
+                lv_theme_get_color_primary(screen),
+                lv_theme_get_color_secondary(screen),
+                LV_THEME_DEFAULT_DARK,
+                font
+            );
+        }
+#endif
+        // The display layers are independent inheritance roots. Updating all of them makes
+        // the new size visible immediately in regular screens, overlays, and the status bar.
+        lv_obj_set_style_text_font(lv_display_get_screen_active(display), font, LV_PART_MAIN);
+        lv_obj_set_style_text_font(lv_display_get_layer_top(display), font, LV_PART_MAIN);
+        lv_obj_set_style_text_font(lv_display_get_layer_sys(display), font, LV_PART_MAIN);
+        lv_obj_set_style_text_font(lv_display_get_layer_bottom(display), font, LV_PART_MAIN);
+    }
+}
+
 void attachDevices() {
     LOG_I(TAG, "Adding devices");
 
@@ -55,6 +99,7 @@ void attachDevices() {
         if (rotation != lv_display_get_rotation(primary_lvgl_display)) {
             lv_display_set_rotation(primary_lvgl_display, rotation);
         }
+        applyFontSize(settings.fontSize);
     }
 
     // Start touch