How to cycle images on
the GC9A01 with
batch conversion

for f in ~/Downloads/myimages/*.png; do name=$(basename "$f" .png); python3 ~/image_to_rgb565.py "$f" "$name"; done

/*
 * We stand on the shoulders of giants when we build
 * with knowledge gained from others' efforts.
 * That doesn't make us giants. Be humble.
 * Create with care. Open source is the way.
 *
 * GC9A01 Cycling Multiple Images
 * -------------------------------
 * Cycles through multiple custom RGB565 images on a GC9A01
 * 240x240 round IPS TFT display via SPI using Arduino_GFX_Library.
 * Images are pre-converted from PNG using image_to_rgb565.py.
 *
 * Board:   ESP32 Dev Board (38-pin)
 * Library: Arduino_GFX_Library by Moon On Our Nation
 *
 * Partition: Tools -> Partition Scheme -> Huge APP (3MB No OTA)
 *
 * Wiring:
 *   VCC -> 3.3V or 5V   GND -> GND
 *   SCL -> GPIO 18       SDA -> GPIO 23
 *   DC  -> GPIO 27       CS  -> GPIO 5
 *   RST -> GPIO 4
 *
 * Open source - MIT Licence
 * Full guide:
 * https://electroniczoology.com/guides/how-to-cycle-images-gc9a01-esp32
 *
 * Electronic Zoology - field notes from the garage
 */

#include <Arduino_GFX_Library.h>

// ---- your images - edit here ----
#include "face1.h"
#include "face2.h"
#include "face3.h"

const uint16_t* images[] = { face1, face2, face3 };
#define NUM_IMAGES (sizeof(images) / sizeof(images[0]))  // auto-counts
// ----------------------------------

#define SWAP_MS 5000        // swap interval in milliseconds

#define TFT_DC  27
#define TFT_CS   5
#define TFT_RST  4

Arduino_DataBus *bus = new Arduino_HWSPI(TFT_DC, TFT_CS);
Arduino_GFX *gfx = new Arduino_GC9A01(bus, TFT_RST, 0, true);
uint8_t idx = 0;
unsigned long lastSwap = 0;

void setup() {
  Serial.begin(115200);
  gfx->begin();
  gfx->fillScreen(0x0000);
  gfx->draw16bitRGBBitmap(0, 0, (uint16_t*)images[0], 240, 240);
  lastSwap = millis();
}

void loop() {
  if (millis() - lastSwap >= SWAP_MS) {
    lastSwap = millis();
    idx = (idx + 1) % NUM_IMAGES;
    gfx->draw16bitRGBBitmap(0, 0, (uint16_t*)images[idx], 240, 240);
  }
}