Touch.h

/**
* @brief This function presents the user with 4 points to touch and saves
         that data to a claibration file.
*
* @param none
*
* @return none
*
* @note If USECAPTOUCH is defined we do not need to calibrate touch
*/
void touch_calibrate()
{
  uint16_t calData[5];
  uint8_t calDataOK = 0;

  // check if calibration file exists and size is correct
  if (FILESYSTEM.exists(CALIBRATION_FILE))
  {
    if (REPEAT_CAL)
    {
      // Delete if we want to re-calibrate
      FILESYSTEM.remove(CALIBRATION_FILE);
    }
    else
    {
      File f = FILESYSTEM.open(CALIBRATION_FILE, "r");
      if (f)
      {
        if (f.readBytes((char *)calData, 14) == 14)
          calDataOK = 1;
        f.close();
      }
    }
  }

  if (calDataOK && !REPEAT_CAL)
  {
    // calibration data valid
    tft.setTouch(calData);
  }
  else
  {
    // data not valid so recalibrate
    tft.fillScreen(TFT_BLACK);
    tft.setCursor(20, 0);
    tft.setTextFont(2);
    tft.setTextSize(1);
    tft.setTextColor(TFT_WHITE, TFT_BLACK);

    tft.println("Touch corners as indicated");

    tft.setTextFont(1);
    tft.println();

    if (REPEAT_CAL)
    {
      tft.setTextColor(TFT_RED, TFT_BLACK);
      tft.println("Set REPEAT_CAL to false to stop this running again!");
    }

    tft.calibrateTouch(calData, TFT_MAGENTA, TFT_BLACK, 15);

    tft.setTextColor(TFT_GREEN, TFT_BLACK);
    tft.println("Calibration complete!");

    // store data
    File f = FILESYSTEM.open(CALIBRATION_FILE, "w");
    if (f)
    {
      f.write((const unsigned char *)calData, 14);
      f.close();
    }
  }
}