import cv2

# Input / Output paths
input_path = "nearest_overlay.png"
output_path = "nearest_overlay_with_arrow.png"

# Load image
img = cv2.imread(input_path)

# Get image dimensions
h, w = img.shape[:2]

# Define arrow start (bottom center)
start_point = (w // 2, h - 20)

# Define arrow end (toward top center)
end_y = int(h - h / 3)   # = 2h/3
end_point = (w // 2, end_y)

# Arrow properties
color = (0, 0, 255)   # Red (BGR format)
thickness = 8
tip_length = 0.05

# Draw arrow
cv2.arrowedLine(
    img,
    start_point,
    end_point,
    color,
    thickness,
    tipLength=tip_length
)

# Save result
cv2.imwrite(output_path, img)

print("Saved to:", output_path)