frigate/frigate/util.py

import numpy as np
import cv2

# convert shared memory array into numpy array
def tonumpyarray(mp_arr):
    return np.frombuffer(mp_arr.get_obj(), dtype=np.uint8)

def draw_box_with_label(frame, x_min, y_min, x_max, y_max, label):
    color = (255,0,0)
    cv2.rectangle(frame, (x_min, y_min), 
        (x_max, y_max), 
        color, 2)
    font_scale = 0.5
    font = cv2.FONT_HERSHEY_SIMPLEX
    # get the width and height of the text box
    size = cv2.getTextSize(label, font, fontScale=font_scale, thickness=2)
    text_width = size[0][0]
    text_height = size[0][1]
    line_height = text_height + size[1]
    # set the text start position
    text_offset_x = x_min
    text_offset_y = 0 if y_min < line_height else y_min - (line_height+8)
    # make the coords of the box with a small padding of two pixels
    textbox_coords = ((text_offset_x, text_offset_y), (text_offset_x + text_width + 2, text_offset_y + line_height))
    cv2.rectangle(frame, textbox_coords[0], textbox_coords[1], color, cv2.FILLED)
    cv2.putText(frame, label, (text_offset_x, text_offset_y + line_height - 3), font, fontScale=font_scale, color=(0, 0, 0), thickness=2)