Refactor battery color calculation logic into `BatteryIcon::ColorFromPercentage()`.

1 files changed, 10 insertions, 0 deletions

diff --git a/src/displayapp/screens/BatteryIcon.cpp b/src/displayapp/screens/BatteryIcon.cpp
index 6194807d..ec740e93 100644
--- a/src/displayapp/screens/BatteryIcon.cpp
+++ b/src/displayapp/screens/BatteryIcon.cpp
@@ -3,6 +3,7 @@
 #include "displayapp/screens/Symbols.h"
 #include "displayapp/icons/battery/batteryicon.c"
 #include "displayapp/InfiniTimeTheme.h"
+#include <lvgl/src/lv_misc/lv_color.h>
 
 using namespace Pinetime::Applications::Screens;
 
@@ -51,3 +52,12 @@ const char* BatteryIcon::GetPlugIcon(bool isCharging) {
   else
     return "";
 }
+
+lv_color_t BatteryIcon::ColorFromPercentage(int batteryPercent) {
+  // HSV color model has red at 0° and green at 120°.
+  // We lock saturation and brightness at 100% and traverse the cylinder
+  // between red and green, thus avoiding the darker RGB on medium battery
+  // charges and giving us a much nicer color range.
+  const uint8_t hue = batteryPercent * 120 / 100;
+  return lv_color_hsv_to_rgb(hue, 100, 100);
+}