Ho would i make a function variable move to .ino main varible

Ok so ive finally got the screen displaying etc and ive made a “calibrate” function in ui_events.c. i need to pass the pitch value to the ui.ino pitch value to change it.

This is the calibrate function

void calibrate(lv_event_t * e)
  // Retrieve the values from ui_FirstPos and ui_SecPos text areas
  const char* firstPosText = lv_textarea_get_text(ui_FirstPos);
  const char* secPosText = lv_textarea_get_text(ui_SecPos);

  // Convert the text values to integers
  int firstPos = atoi(firstPosText);
  int secPos = atoi(secPosText);

  // Calculate the difference in positions
  int posDifference = secPos - firstPos;

  // Calculate the pitch adjustment factor
  // Assuming a desired range of motion in millimeters
  float desiredRange = 100.0;  // Adjust this value according to your requirements
  float calculatedPitch = desiredRange / posDifference;

  // Adjust the pitch or encoder settings based on the calculated value
  // For example:
  pitch = calculatedPitch;  // Update the pitch value


im sure it something simple but i have been hitting a brick wall ATM