Add low battery indicator to StatusIcons, digital and analog watchfaces

Define deepOrange color in InfiniTimeTheme

src/displayapp/InfiniTimeTheme.h

@@ -3,6 +3,7 @@
 #include <lvgl/lvgl.h>
 
 namespace Colors {
+  static constexpr lv_color_t deepOrange = LV_COLOR_MAKE(0xff, 0x40, 0x0);
   static constexpr lv_color_t orange = LV_COLOR_MAKE(0xff, 0xb0, 0x0);
   static constexpr lv_color_t green = LV_COLOR_MAKE(0x0, 0xb0, 0x0);
   static constexpr lv_color_t blue = LV_COLOR_MAKE(0x0, 0x50, 0xff);

src/displayapp/screens/BatteryIcon.cpp

@@ -2,9 +2,12 @@
 #include <cstdint>
 #include "displayapp/screens/Symbols.h"
 #include "displayapp/icons/battery/batteryicon.c"
+#include "displayapp/InfiniTimeTheme.h"
 
 using namespace Pinetime::Applications::Screens;
 
+BatteryIcon::BatteryIcon(bool colorOnLowBattery) : colorOnLowBattery {colorOnLowBattery} {};
+
 void BatteryIcon::Create(lv_obj_t* parent) {
   batteryImg = lv_img_create(parent, nullptr);
   lv_img_set_src(batteryImg, &batteryicon);
@@ -23,6 +26,17 @@ lv_obj_t* BatteryIcon::GetObject() {
 void BatteryIcon::SetBatteryPercentage(uint8_t percentage) {
   lv_obj_set_height(batteryJuice, percentage * 14 / 100);
   lv_obj_realign(batteryJuice);
+  if (colorOnLowBattery) {
+    static constexpr int lowBatteryThreshold = 15;
+    static constexpr int criticalBatteryThreshold = 5;
+    if (percentage > lowBatteryThreshold) {
+      SetColor(LV_COLOR_WHITE);
+    } else if (percentage > criticalBatteryThreshold) {
+      SetColor(LV_COLOR_ORANGE);
+    } else {
+      SetColor(Colors::deepOrange);
+    }
+  }
 }
 
 void BatteryIcon::SetColor(lv_color_t color) {

src/displayapp/screens/BatteryIcon.h

@@ -7,6 +7,7 @@ namespace Pinetime {
     namespace Screens {
       class BatteryIcon {
       public:
+        explicit BatteryIcon(bool colorOnLowBattery);
         void Create(lv_obj_t* parent);
 
         void SetColor(lv_color_t);
@@ -19,6 +20,7 @@ namespace Pinetime {
       private:
         lv_obj_t* batteryImg;
         lv_obj_t* batteryJuice;
+        bool colorOnLowBattery = false;
       };
     }
   }

src/displayapp/screens/WatchFaceAnalog.cpp

@@ -49,6 +49,7 @@ WatchFaceAnalog::WatchFaceAnalog(Controllers::DateTime& dateTimeController,
                                  Controllers::NotificationManager& notificationManager,
                                  Controllers::Settings& settingsController)
   : currentDateTime {{}},
+    batteryIcon(true),
     dateTimeController {dateTimeController},
     batteryController {batteryController},
     bleController {bleController},

src/displayapp/screens/WatchFaceCasioStyleG7710.cpp

@@ -23,6 +23,7 @@ WatchFaceCasioStyleG7710::WatchFaceCasioStyleG7710(Controllers::DateTime& dateTi
                                                    Controllers::MotionController& motionController,
                                                    Controllers::FS& filesystem)
   : currentDateTime {{}},
+    batteryIcon(false),
     dateTimeController {dateTimeController},
     batteryController {batteryController},
     bleController {bleController},

src/displayapp/screens/WatchFacePineTimeStyle.cpp

@@ -50,6 +50,7 @@ WatchFacePineTimeStyle::WatchFacePineTimeStyle(Controllers::DateTime& dateTimeCo
                                                Controllers::Settings& settingsController,
                                                Controllers::MotionController& motionController)
   : currentDateTime {{}},
+    batteryIcon(false),
     dateTimeController {dateTimeController},
     batteryController {batteryController},
     bleController {bleController},

src/displayapp/widgets/StatusIcons.cpp

@@ -4,7 +4,7 @@
 using namespace Pinetime::Applications::Widgets;
 
 StatusIcons::StatusIcons(const Controllers::Battery& batteryController, const Controllers::Ble& bleController)
-  : batteryController {batteryController}, bleController {bleController} {
+  : batteryIcon(true), batteryController {batteryController}, bleController {bleController} {
 }
 
 void StatusIcons::Create() {