utils.py

import math
import screeninfo

def calculate_distance(p1, p2):
    """Calculates Euclidean distance between two points."""
    x1, y1 = p1
    x2, y2 = p2
    return math.sqrt((x1 - x2)**2 + (y1 - y2)**2)

def get_screen_size():
    """Gets the primary screen resolution."""
    try:
        screen = screeninfo.get_monitors()[0]
        return screen.width, screen.height
    except Exception:
        return 1920, 1080  # Default fallback

def map_coordinates(norm_x, norm_y, screen_w, screen_h, calib_min_x=0, calib_max_x=1, calib_min_y=0, calib_max_y=1):
    """
    Maps normalized coordinates (relative to eye/calibration) to screen coordinates.
    """
    # Inverse interpolation based on calibration range
    # screen_x = ((iris_x - min_x) / (max_x - min_x)) * screen_width
    
    range_x = calib_max_x - calib_min_x
    range_y = calib_max_y - calib_min_y
    
    if range_x == 0: range_x = 1
    if range_y == 0: range_y = 1
    
    rel_x = (norm_x - calib_min_x) / range_x
    rel_y = (norm_y - calib_min_y) / range_y
    
    screen_x = int(rel_x * screen_w)
    screen_y = int(rel_y * screen_h)
    
    return screen_x, screen_y

def clamp(value, min_val, max_val):
    return max(min_val, min(value, max_val))

def calculate_ear(eye_landmarks, landmarks_list):
    """
    Calculates Eye Aspect Ratio (EAR).
    eye_landmarks: Indices of eye landmarks (p1, p2, p3, p4, p5, p6)
    landmarks_list: List of all facial landmarks with (x, y) coordinates
    """
    # Vertical distances
    A = calculate_distance(landmarks_list[eye_landmarks[1]], landmarks_list[eye_landmarks[5]])
    B = calculate_distance(landmarks_list[eye_landmarks[2]], landmarks_list[eye_landmarks[4]])
    
    # Horizontal distance
    C = calculate_distance(landmarks_list[eye_landmarks[0]], landmarks_list[eye_landmarks[3]])
    
    if C == 0:
        return 0.0
        
    ear = (A + B) / (2.0 * C)
    return ear