esp32 - backlight control and cell colors

/*******************************************************************
    Combined LDR and Backlight Control with Smoothing and Presets
    - Automatically adjusts screen brightness based on ambient light
    - Adds smoothing to avoid flicker
    - Includes Day/Night preset brightness levels
 *******************************************************************/

#include <TFT_eSPI.h>
TFT_eSPI tft = TFT_eSPI();

#define LCD_BACK_LIGHT_PIN 21  // PWM pin for screen backlight
#define LDR_PIN 34             // Analog pin connected to LDR

// PWM settings
const int pwmChannel = 0;
const int pwmFreq = 5000;        // 5kHz PWM frequency
const int pwmResolution = 12;    // 12-bit resolution (0-4095)

// Smoothing settings
const int numReadings = 10;
int readings[numReadings];       // Array to store LDR readings
int readIndex = 0;
long total = 0;
int average = 0;
string curr_bg_color = "";
string curr_text_color = "";

// Brightness presets
const int DAY_BRIGHTNESS = 4095;  // Full brightness
const int NIGHT_BRIGHTNESS = 300; // Low brightness

void setup() {
  Serial.begin(115200);
  tft.init();
  tft.setRotation(1);
  tft.fillScreen(TFT_BLACK);
  tft.setTextColor(TFT_WHITE, TFT_BLACK);
  tft.setTextSize(2);
  tft.setCursor(0, 0);
  tft.println("Auto Brightness Display");

  analogReadResolution(12); // Ensure analog input is 0–4095

  // Setup PWM for backlight
  ledcSetup(pwmChannel, pwmFreq, pwmResolution);
  ledcAttachPin(LCD_BACK_LIGHT_PIN, pwmChannel);

  // Initialize smoothing array
  for (int i = 0; i < numReadings; i++) {
    readings[i] = 0;
  }
}

void loop() {
  total = total - readings[readIndex];
  readings[readIndex] = analogRead(LDR_PIN);
  total = total + readings[readIndex];
  readIndex = (readIndex + 1) % numReadings;
  average = total / numReadings;

  Serial.print("Smoothed LDR Value: ");
  Serial.println(average);

  // Determine brightness preset based on ambient light
  int brightness;
  if (average < 1500) {
    brightness = DAY_BRIGHTNESS; // Bright outside
    lv_obj_set_style_bg_color(lv_scr_act(), lv_color_make(255, 255, 255), LV_PART_MAIN);
    lv_obj_set_style_text_color(table, lv_color_black(), LV_PART_ITEMS);
    lv_obj_set_style_bg_color(table, lv_color_white(), LV_PART_MAIN);
    curr_bg_color = "255, 255, 255";
    curr_text_color = "0, 0, 0";
  } else {
    brightness = NIGHT_BRIGHTNESS; // Dark environment
    lv_obj_set_style_bg_color(lv_scr_act(), lv_color_make(30, 30, 30), LV_PART_MAIN);
    lv_obj_set_style_text_color(table, lv_color_white(), LV_PART_ITEMS);
    //lv_obj_set_style_bg_color(table, lv_color_black(), LV_PART_MAIN);
    lv_obj_set_style_bg_color(table, lv_color_make(30, 30, 30), LV_PART_MAIN);
    curr_bg_color = "30, 30, 30";
    curr_text_color = "255, 255, 255";
  }
  ledcWrite(pwmChannel, brightness);

  delay(200);
}

void cell_color_mod(int row, int col, string col_color, string text_color) {
    lv_table_set_cell_text_color(table, row, col, lv_color_make(text_color));
    lv_table_set_cell_bg_color(table, row, col, lv_color_make(col_color));
    //lv_table_set_cell_bg_color(table, row, col, lv_palette_main(LV_PALETTE_RED));
}