Tough Touch Screen

#include <M5Unified.h>
#include <M5GFX.h>

m5::touch_detail_t touchDetail;

int width, height;

void setup() {
  M5.begin();
  M5.Display.setRotation(1);
  M5.Display.setFont(&fonts::DejaVu40);

  width = M5.Display.width();
  height = M5.Display.height();

  Serial.begin(115200);
  Serial.println("Start touching!");
  M5.Display.print("Start touching!");
}

void loop() {
  M5.update();
  touchDetail = M5.Touch.getDetail();

  if (touchDetail.isPressed()) {
    Serial.printf("x:%d, y:%d\r\n", touchDetail.x, touchDetail.y);

    for (int i = 0; i < width; i += 10) {
      for (int j = 0; j < height; j += 10) {
        uint8_t cr = map((touchDetail.x - i) % width, 0, width, 0, 256);
        uint8_t cg = map((touchDetail.y - j) % height, 0, height, 0, 256);
        uint16_t color = M5.Display.color565(cr, cg, 255 - (cr + cg) / 2);
        M5.Display.fillRect(i, j, 10, 10, color);
      }
    }
  }
}