Unit Neco Arduino Tutorial

#include <M5Unified.h>
#include <FastLED.h>

constexpr uint8_t LED_COUNT = 35;
constexpr uint8_t BRIGHTNESS = 20;
constexpr uint8_t DATA_PIN = 9;
constexpr uint16_t UI_BG = 0x1082;
constexpr uint16_t UI_PANEL = 0x2104;
constexpr uint16_t UI_HEADER = 0x0349;
constexpr uint16_t UI_MUTED = 0xBDF7;

CRGB pixels[LED_COUNT];
M5Canvas canvas(&M5.Display);
int button_pin = -1;
uint8_t color_index = 0;
bool last_button = false;

CRGB paletteColor(uint8_t index)
{
    const uint8_t r = (index == 0) ? 244 : (index == 1 ? 30 : 36);
    const uint8_t g = (index == 1) ? 180 : (index == 2 ? 210 : 36);
    const uint8_t b = (index == 2) ? 208 : (index == 0 ? 80 : 90);
    return CRGB(r, g, b);
}

CRGB paletteColor()
{
    return paletteColor(color_index);
}

uint16_t color565(const CRGB& color)
{
    return (static_cast<uint16_t>(color.r & 0xF8) << 8) |
           (static_cast<uint16_t>(color.g & 0xFC) << 3) | (color.b >> 3);
}

void showPixels()
{
    fill_solid(pixels, LED_COUNT, paletteColor());
    FastLED.show();
}

void drawColorSwatch(int16_t x, uint8_t index, const char* label)
{
    const bool selected = index == color_index;
    const uint16_t border = selected ? color565(paletteColor(index)) : UI_MUTED;
    canvas.fillRoundRect(x, 152, 92, 48, 5, UI_PANEL);
    canvas.drawRoundRect(x, 152, 92, 48, 5, border);
    canvas.fillCircle(x + 18, 176, 9, color565(paletteColor(index)));
    canvas.setFont(&fonts::Font2);
    canvas.setTextDatum(textdatum_t::middle_left);
    canvas.setTextColor(selected ? TFT_WHITE : UI_MUTED, UI_PANEL);
    canvas.drawString(label, x + 34, 176);
}

void drawStatus(bool pressed)
{
    char detail[24] = {};
    snprintf(detail, sizeof(detail), "COLOR %u  /  %u PIXELS",
             static_cast<unsigned>(color_index + 1), LED_COUNT);

    canvas.fillScreen(UI_BG);
    canvas.fillRect(0, 0, 320, 42, UI_HEADER);
    canvas.setFont(&fonts::Font4);
    canvas.setTextDatum(textdatum_t::middle_center);
    canvas.setTextColor(TFT_WHITE, UI_HEADER);
    canvas.drawString("UNIT NECO", 160, 16);
    canvas.setFont(&fonts::Font2);
    canvas.setTextColor(UI_MUTED, UI_HEADER);
    canvas.drawString("COLOR CONTROL  /  STATUS", 160, 33);

    canvas.fillRoundRect(12, 54, 296, 84, 6, UI_PANEL);
    canvas.drawRoundRect(12, 54, 296, 84, 6, color565(paletteColor()));
    canvas.fillCircle(52, 96, 25, color565(paletteColor()));
    canvas.setTextDatum(textdatum_t::middle_left);
    canvas.setTextColor(TFT_WHITE, UI_PANEL);
    canvas.drawString("CURRENT COLOR", 94, 78);
    canvas.setTextColor(UI_MUTED, UI_PANEL);
    canvas.drawString(detail, 94, 101);
    canvas.setTextColor(pressed ? TFT_ORANGE : TFT_GREEN, UI_PANEL);
    canvas.drawString(pressed ? "BUTTON DOWN" : "BUTTON READY", 94, 122);

    drawColorSwatch(12, 0, "PINK");
    drawColorSwatch(114, 1, "GREEN");
    drawColorSwatch(216, 2, "BLUE");

    canvas.fillRect(0, 214, 320, 26, UI_HEADER);
    canvas.setTextDatum(textdatum_t::middle_center);
    canvas.setTextColor(TFT_WHITE, UI_HEADER);
    canvas.drawString("PRESS BUTTON  |  COLOR CHANGE", 160, 227);
    canvas.pushSprite(0, 0);
}

void setup()
{
    M5.begin();
    Serial.begin(115200);
    canvas.setColorDepth(16);
    canvas.createSprite(320, 240);
    button_pin = M5.getPin(m5::pin_name_t::port_b_pin1);
    pinMode(button_pin, INPUT_PULLUP);
    FastLED.addLeds<WS2812B, DATA_PIN, GRB>(pixels, LED_COUNT)
        .setCorrection(TypicalLEDStrip);
    FastLED.setBrightness(BRIGHTNESS);
    showPixels();
    drawStatus(false);
}

void loop()
{
    const bool button = digitalRead(button_pin) == LOW;
    if (button && !last_button) {
        color_index = (color_index + 1) % 3;
        showPixels();
        Serial.printf("Color: %u\n", color_index + 1);
    }
    if (button != last_button) {
        drawStatus(button);
    }
    last_button = button;
    delay(10);
}