Car Multi-Use Display

#include <Arduino.h>
#include <Wire.h>
#include <TinyGPS++.h>
#include <RTClib.h>
#include <Adafruit_BME280.h>
#include <Arduino_GFX_Library.h>

constexpr int TFT_CS_PIN = 17;
constexpr int TFT_SCK_PIN = 18;
constexpr int TFT_MOSI_PIN = 19;
constexpr int TFT_DC_PIN = 20;
constexpr int TFT_RST_PIN = 21;
constexpr int GPS_RX_PIN = 1;
constexpr int I2C_SDA_PIN = 4;
constexpr int I2C_SCL_PIN = 5;

constexpr uint16_t COLOR_BG = 0x0841;
constexpr uint16_t COLOR_PANEL = 0x18C3;
constexpr uint16_t COLOR_TEXT = 0xFFFF;
constexpr uint16_t COLOR_MUTED = 0xBDF7;
constexpr uint16_t COLOR_ACCENT = 0x07FF;
constexpr uint16_t COLOR_GOOD = 0x07E0;
constexpr uint16_t COLOR_WARN = 0xFD20;

Arduino_DataBus *displayBus = new Arduino_HWSPI(TFT_DC_PIN, TFT_CS_PIN, &SPI, true);
Arduino_GFX *display = new Arduino_ILI9488(displayBus, TFT_RST_PIN, 1, true);
TinyGPSPlus gps;
RTC_DS3231 rtc;
Adafruit_BME280 bme;

bool rtcFound = false;
bool bmeFound = false;
bool rtcSyncedFromGps = false;
unsigned long lastRefreshMs = 0;
unsigned long lastSensorMs = 0;
float temperatureC = NAN;
float humidity = NAN;
float pressureHpa = NAN;
String lastSpeed;
String lastTime;
String lastPosition;
String lastClimate;
String lastFix;

void drawLabel(const char *label, int16_t x, int16_t y) {
  display->setTextSize(1);
  display->setTextColor(COLOR_MUTED);
  display->setCursor(x, y);
  display->print(label);
}

void drawValue(const String &value, int16_t x, int16_t y, uint8_t size, uint16_t color) {
  display->setTextSize(size);
  display->setTextColor(color);
  display->setCursor(x, y);
  display->print(value);
}

void drawFrame() {
  display->fillScreen(COLOR_BG);
  display->fillRect(8, 8, 464, 58, COLOR_PANEL);
  display->fillRect(8, 76, 224, 236, COLOR_PANEL);
  display->fillRect(240, 76, 232, 112, COLOR_PANEL);
  display->fillRect(240, 196, 232, 116, COLOR_PANEL);
  drawLabel("OFFLINE CAR DASHBOARD", 20, 18);
  drawLabel("TIME (UTC)", 20, 39);
  drawLabel("GPS SPEED", 22, 89);
  drawLabel("GPS POSITION", 252, 89);
  drawLabel("CABIN / BAROMETER", 252, 209);
}

String twoDigits(int value) {
  return value < 10 ? "0" + String(value) : String(value);
}

void updateCell(String &previous, const String &next, int16_t x, int16_t y, int16_t w, int16_t h, uint8_t size, uint16_t color) {
  if (previous == next) return;
  display->fillRect(x, y, w, h, COLOR_PANEL);
  drawValue(next, x, y, size, color);
  previous = next;
}

void readGps() {
  while (Serial1.available() > 0) {
    gps.encode(Serial1.read());
  }
}

String clockText() {
  if (gps.time.isValid() && gps.date.isValid()) {
    return twoDigits(gps.time.hour()) + ":" + twoDigits(gps.time.minute()) + ":" + twoDigits(gps.time.second()) + "  " + twoDigits(gps.date.day()) + "/" + twoDigits(gps.date.month()) + "/" + String(gps.date.year());
  }
  if (rtcFound) {
    DateTime now = rtc.now();
    return twoDigits(now.hour()) + ":" + twoDigits(now.minute()) + ":" + twoDigits(now.second()) + "  " + twoDigits(now.day()) + "/" + twoDigits(now.month()) + "/" + String(now.year());
  }
  return "WAITING FOR TIME";
}

void refreshDashboard() {
  String speed = "NO FIX";
  String position = "Waiting for satellites";
  String fix = "GPS: searching";
  if (gps.location.isValid()) {
    speed = String(gps.speed.kmph(), 0) + " km/h";
    position = String(gps.location.lat(), 5) + ", " + String(gps.location.lng(), 5);
    fix = "GPS: fixed  " + String(gps.satellites.isValid() ? gps.satellites.value() : 0) + " sats";
  }
  if (!rtcSyncedFromGps && rtcFound && gps.date.isValid() && gps.time.isValid()) {
    rtc.adjust(DateTime(gps.date.year(), gps.date.month(), gps.date.day(), gps.time.hour(), gps.time.minute(), gps.time.second()));
    rtcSyncedFromGps = true;
  }
  String climate = "Sensor not found";
  if (bmeFound && !isnan(temperatureC)) {
    climate = String(temperatureC, 1) + " C   " + String(humidity, 0) + " %\n" + String(pressureHpa, 0) + " hPa";
  }
  updateCell(lastTime, clockText(), 118, 34, 340, 26, 2, COLOR_TEXT);
  updateCell(lastSpeed, speed, 24, 120, 200, 56, 4, gps.location.isValid() ? COLOR_GOOD : COLOR_WARN);
  updateCell(lastFix, fix, 24, 190, 200, 24, 1, COLOR_MUTED);
  updateCell(lastPosition, position, 252, 117, 212, 52, 2, COLOR_ACCENT);
  if (lastClimate != climate) {
    display->fillRect(252, 236, 212, 65, COLOR_PANEL);
    display->setTextSize(2);
    display->setTextColor(bmeFound ? COLOR_TEXT : COLOR_WARN);
    display->setCursor(252, 236);
    display->print(climate);
    lastClimate = climate;
  }
}

void setup() {
  Wire.setSDA(I2C_SDA_PIN);
  Wire.setSCL(I2C_SCL_PIN);
  Wire.begin();
  Serial1.setRX(GPS_RX_PIN);
  Serial1.begin(9600);
  display->begin();
  display->setRotation(1);
  drawFrame();
  rtcFound = rtc.begin();
  bmeFound = bme.begin(0x77, &Wire);
  refreshDashboard();
}

void loop() {
  readGps();
  unsigned long now = millis();
  if (bmeFound && now - lastSensorMs >= 2000) {
    temperatureC = bme.readTemperature();
    humidity = bme.readHumidity();
    pressureHpa = bme.readPressure() / 100.0F;
    lastSensorMs = now;
  }
  if (now - lastRefreshMs >= 500) {
    refreshDashboard();
    lastRefreshMs = now;
  }
  delay(10);
}