functions.py

import cv2 as cv
import numpy as np
from typing import List, Tuple

LINE_COLOR = (0, 140, 255)
WHITE_COLOR = (255, 255, 255)

def position_data(lmlist: List[Tuple[int, int]]) -> List[Tuple[int, int]]:
    if len(lmlist) < 21:
        raise ValueError("Landmark list must contain at least 21 points.")

    keys = [0, 4, 5, 8, 9, 12, 16, 20]  
    return [lmlist[i] for i in keys]

def calculate_distance(p1: Tuple[int, int], p2: Tuple[int, int]) -> float:
    return np.linalg.norm(np.array(p1) - np.array(p2))

def draw_line(
    frame: np.ndarray,
    p1: Tuple[int, int],
    p2: Tuple[int, int],
    color: Tuple[int, int, int] = LINE_COLOR,
    thickness: int = 5
) -> np.ndarray:
    cv.line(frame, p1, p2, color, thickness)
    cv.line(frame, p1, p2, WHITE_COLOR, max(1, thickness // 2))
    return frame

def overlay_image(
    target_img: np.ndarray,
    frame: np.ndarray,
    x: int, y: int,
    size: Tuple[int, int] = None
) -> np.ndarray:
    if size:
        try:
            target_img = cv.resize(target_img, size)
        except cv.error as e:
            raise ValueError(f"Error resizing the target image: {e}")

    if target_img.shape[-1] != 4:
        raise ValueError("Target image must have 4 channels (RGBA).")

    b, g, r, a = cv.split(target_img)
    overlay_color = cv.merge((b, g, r))
    mask = cv.medianBlur(a, 5)

    h, w, _ = overlay_color.shape
    if y + h > frame.shape[0] or x + w > frame.shape[1]:
        raise ValueError("Overlay exceeds frame boundaries.")

    roi = frame[y:y + h, x:x + w]

    img1_bg = cv.bitwise_and(roi, roi, mask=cv.bitwise_not(mask))
    img2_fg = cv.bitwise_and(overlay_color, overlay_color, mask=mask)

    frame[y:y + h, x:x + w] = cv.add(img1_bg, img2_fg)

    return frame