text: // Touch screen library with X Y and Z (pressure) readings as well
  // as oversampling to avoid 'bouncing'
  // (c) ladyada / adafruit
  // Code under MIT License
  
  #ifndef _ADAFRUIT_TOUCHSCREEN_H_
  #define _ADAFRUIT_TOUCHSCREEN_H_
  #include <stdint.h>
  
  #if defined(__AVR_ATmega328P__) || defined(__AVR_ATmega32U4__) ||              \
      defined(TEENSYDUINO) || defined(__AVR_ATmega2560__) ||                     \
      defined(__AVR_ATmega4809__)
  typedef volatile uint8_t RwReg;
  #elif defined(ARDUINO_STM32_FEATHER)
  typedef volatile uint32 RwReg;
  #elif defined(NRF52_SERIES) || defined(ESP32) || defined(ESP8266) ||           \
      defined(ARDUINO_ARCH_STM32)
  typedef volatile uint32_t RwReg;
  #else
  typedef volatile uint32_t RwReg;
  #endif
  
  #if defined(__AVR__) || defined(TEENSYDUINO) || defined(ARDUINO_ARCH_SAMD)
  #define USE_FAST_PINIO
  #endif
  
  /** Object that encapsulates the X,Y, and Z/pressure measurements for a touch
   * event. */
  class TSPoint {
  public:
    TSPoint(void);
    TSPoint(int16_t x, int16_t y, int16_t z);
  
    bool operator==(TSPoint);
    bool operator!=(TSPoint);
  
    int16_t x, ///< state variable for the x value
        y,     ///< state variable for the y value
        z;     ///< state variable for the z value
  };
  /** Object that controls and keeps state for a touch screen. */
  
  class TouchScreen {
  public:
    /**
     * @brief Construct a new Touch Screen object
     *
     * @param xp X+ pin. Must be an analog pin
     * @param yp Y+ pin. Must be an analog pin
     * @param xm X- pin. Can be a digital pin
     * @param ym Y- pin. Can be a digital pin
     * @param rx The resistance in ohms between X+ and X- to calibrate pressure
     * sensing
     */
    TouchScreen(uint8_t xp, uint8_t yp, uint8_t xm, uint8_t ym, uint16_t rx);
  
    /**
     * @brief **NOT IMPLEMENTED** Test if the screen has been touched
     *
     * @return true : touch detected false: no touch detected
     */
    bool isTouching(void);
    uint16_t pressure(void);
    int readTouchY();
    int readTouchX();
    TSPoint getPoint();
    int16_t pressureThreshhold; ///< Pressure threshold for `isTouching`
  
  private:
    uint8_t _yp, _ym, _xm, _xp;
    uint16_t _rxplate;
  
  #if defined(USE_FAST_PINIO)
    volatile RwReg *xp_port, *yp_port, *xm_port, *ym_port;
    RwReg xp_pin, xm_pin, yp_pin, ym_pin;
  #endif
  };
  
  #endif
  